[PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Wang Sen
When using the commands below to write some data to a virtio-scsi LUN of the 
QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.

# sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
# sudo mount /dev/sdb /mnt
# dd if=/dev/zero of=/mnt/file bs=1M count=1024

In current implementation, sg_set_buf is called to add buffers to sg list which
is put into the virtqueue eventually. But there are some HighMem pages in 
table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
return NULL value. This will cause QEMU exit when virtqueue_map_sg is called 
in QEMU because an invalid GPA is passed by virtqueue.

My solution is using sg_set_page instead of sg_set_buf.

I have tested the patch on my workstation. QEMU would not crash any more.

Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
---
 drivers/scsi/virtio_scsi.c |3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 1b38431..fc5c88a 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -198,7 +198,8 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
unsigned int *p_idx,
int i;
 
for_each_sg(table-sgl, sg_elem, table-nents, i)
-   sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
+   sg_set_page(sg[idx++], sg_page(sg_elem), sg_elem-length,
+   sg_elem-offset);
 
*p_idx = idx;
 }
-- 
1.7.9.5

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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 10:29, Wang Sen ha scritto:
 When using the commands below to write some data to a virtio-scsi LUN of the 
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.
 
   # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
   # sudo mount /dev/sdb /mnt
   # dd if=/dev/zero of=/mnt/file bs=1M count=1024
 
 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But there are some HighMem pages in 
 table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called 
 in QEMU because an invalid GPA is passed by virtqueue.

Heh, I was compiling (almost) the same patch as we speak. :)

I've never seen QEMU crash; the VM would more likely just fail to boot
with a panic.  But it's the same bug anyway.

 My solution is using sg_set_page instead of sg_set_buf.
 
 I have tested the patch on my workstation. QEMU would not crash any more.
 
 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)
 
 diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
 index 1b38431..fc5c88a 100644
 --- a/drivers/scsi/virtio_scsi.c
 +++ b/drivers/scsi/virtio_scsi.c
 @@ -198,7 +198,8 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
 unsigned int *p_idx,
   int i;
  
   for_each_sg(table-sgl, sg_elem, table-nents, i)
 - sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
 + sg_set_page(sg[idx++], sg_page(sg_elem), sg_elem-length,
 + sg_elem-offset);

This can simply be

   sg[idx++] = *sg_elem;

Can you repost it with this change, and also add sta...@vger.kernel.org
to the Cc?  Thanks very much!

Paolo
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 11:44 AM, Paolo Bonzini wrote:

 Il 25/07/2012 10:29, Wang Sen ha scritto:
 When using the commands below to write some data to a virtio-scsi LUN of the 
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
 crash.

  # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
  # sudo mount /dev/sdb /mnt
  # dd if=/dev/zero of=/mnt/file bs=1M count=1024

 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But there are some HighMem pages in 
 table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called 
 in QEMU because an invalid GPA is passed by virtqueue.
 
 Heh, I was compiling (almost) the same patch as we speak. :)
 
 I've never seen QEMU crash; the VM would more likely just fail to boot
 with a panic.  But it's the same bug anyway.
 
 My solution is using sg_set_page instead of sg_set_buf.

 I have tested the patch on my workstation. QEMU would not crash any more.

 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

 diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
 index 1b38431..fc5c88a 100644
 --- a/drivers/scsi/virtio_scsi.c
 +++ b/drivers/scsi/virtio_scsi.c
 @@ -198,7 +198,8 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
 unsigned int *p_idx,
  int i;
  
  for_each_sg(table-sgl, sg_elem, table-nents, i)
 -sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
 +sg_set_page(sg[idx++], sg_page(sg_elem), sg_elem-length,
 +sg_elem-offset);
 
 This can simply be
 
sg[idx++] = *sg_elem;
 
 Can you repost it with this change, and also add sta...@vger.kernel.org
 to the Cc?  Thanks very much!
 


No! Please use sg_set_page()! Look at sg_set_page(), which calls 
sg_assign_page().
It has all these jump over chained arrays. When you'll start using long
sg_lists (which you should) then jumping from chain to chain must go through
sg_page(sg_elem)  sg_assign_page(), As in the original patch.

Thanks
Boaz

 Paolo
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 11:22, Boaz Harrosh ha scritto:
   for_each_sg(table-sgl, sg_elem, table-nents, i)
  -sg_set_buf(sg[idx++], sg_virt(sg_elem), 
  sg_elem-length);
  +sg_set_page(sg[idx++], sg_page(sg_elem), 
  sg_elem-length,
  +sg_elem-offset);
  
  This can simply be
  
 sg[idx++] = *sg_elem;
  
  Can you repost it with this change, and also add sta...@vger.kernel.org
  to the Cc?  Thanks very much!
  
 
 No! Please use sg_set_page()! Look at sg_set_page(), which calls 
 sg_assign_page().
 It has all these jump over chained arrays. When you'll start using long
 sg_lists (which you should) then jumping from chain to chain must go through
 sg_page(sg_elem)  sg_assign_page(), As in the original patch.

Hi Boaz,

actually it seems to me that using sg_set_page is wrong, because it will
not copy the end marker from table-sgl to sg[].  If something chained
the sg[] scatterlist onto something else, sg_next's test for sg_is_last
would go beyond the table-nents-th item and access invalid memory.

Using chained sglists is on my to-do list, I expect that it would make a
nice performance improvement.  However, I was a bit confused as to
what's the plan there; there is hardly any user, and many arches still
do not define ARCH_HAS_SG_CHAIN.  Do you have any pointer to discussions
or LWN articles?

I would need to add support for the long sglists to virtio; this is not
a problem, but in the past Rusty complained that long sg-lists are not
well suited to virtio (which would like to add elements not just at the
beginning of a given sglist, but also at the end).  It seems to me that
virtio would prefer to work with a struct scatterlist ** rather than a
long sglist.

Paolo
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Stefan Hajnoczi
On Wed, Jul 25, 2012 at 04:00:19PM +0800, Wang Sen wrote:
 When using the commands below to write some data to a virtio-scsi LUN of the 
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.
 
   # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
   # sudo mount /dev/sdb /mnt
   # dd if=/dev/zero of=/mnt/file bs=1M count=1024
 
 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But there are some HighMem pages in 
 table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called 
 in QEMU because an invalid GPA is passed by virtqueue.
 
 My solution is using sg_set_page instead of sg_set_buf.
 
 I have tested the patch on my workstation. QEMU would not crash any more.
 
 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Stefan Hajnoczi stefa...@linux.vnet.ibm.com

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RE: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread Reddy, Sreekanth
Hi,

We have done some analysis on this issue. From our analysis we observed that, 
this issue is reproducible on kernel 3.1.10 onwards but in 3.0.36 this issue is 
not reproducible. So, we have taken the mpt2sas code from 3.1.10 kernel and 
compiled and run it on 3.0.36 kernel. Here this issue is not reproducible (i.e. 
it is working fine). 

From 3.0.36 kernel onwards we have not added any patches that will cause this 
issue. So, what I mean to say is this issue is not because of mpt2sas driver.

Regards,
Sreekanth.  

 -Original Message-
 From: linux-scsi-ow...@vger.kernel.org [mailto:linux-scsi-
 ow...@vger.kernel.org] On Behalf Of Matthias Prager
 Sent: Wednesday, July 25, 2012 3:34 AM
 To: Tejun Heo
 Cc: Robert Trace; linux-scsi@vger.kernel.org; Jens Axboe; Moore, Eric;
 James E.J. Bottomley; Alan; Darrick J. Wong; Matthias Prager
 Subject: Re: 'Device not ready' issue on mpt2sas since 3.1.10
 
 Hello everyone,
 
 I retested with a new firmware (P14 - released today), since it
 contains
 a bunch of sata and SATL fixes (according to the changelog).
 Unfortunately the observed behavior is unchanged (tested on a 3.4.5
 kernel).
 
 Just wanted to let everyone know.
 
 Cheers
 Matthias
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Stefan Hajnoczi
On Wed, Jul 25, 2012 at 10:44:14AM +0200, Paolo Bonzini wrote:
 Il 25/07/2012 10:29, Wang Sen ha scritto:
  When using the commands below to write some data to a virtio-scsi LUN of 
  the 
  QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
  crash.
  
  # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
  # sudo mount /dev/sdb /mnt
  # dd if=/dev/zero of=/mnt/file bs=1M count=1024
  
  In current implementation, sg_set_buf is called to add buffers to sg list 
  which
  is put into the virtqueue eventually. But there are some HighMem pages in 
  table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
  return NULL value. This will cause QEMU exit when virtqueue_map_sg is 
  called 
  in QEMU because an invalid GPA is passed by virtqueue.
 
 Heh, I was compiling (almost) the same patch as we speak. :)
 
 I've never seen QEMU crash; the VM would more likely just fail to boot
 with a panic.  But it's the same bug anyway.

It's not a segfault crash, I think it hits an abort(3) in QEMU's
virtio code when trying to map an invalid guest physical address.

Stefan

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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Sen Wang
2012/7/25 Paolo Bonzini pbonz...@redhat.com:
 Il 25/07/2012 10:29, Wang Sen ha scritto:
 When using the commands below to write some data to a virtio-scsi LUN of the
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
 crash.

   # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
   # sudo mount /dev/sdb /mnt
   # dd if=/dev/zero of=/mnt/file bs=1M count=1024

 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But there are some HighMem pages in
 table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
 in QEMU because an invalid GPA is passed by virtqueue.

 Heh, I was compiling (almost) the same patch as we speak. :)

Uh, what a coincidence! :)


 I've never seen QEMU crash; the VM would more likely just fail to boot
 with a panic.  But it's the same bug anyway.

I never met this before. How this situation happens?


 My solution is using sg_set_page instead of sg_set_buf.

 I have tested the patch on my workstation. QEMU would not crash any more.

 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

 diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
 index 1b38431..fc5c88a 100644
 --- a/drivers/scsi/virtio_scsi.c
 +++ b/drivers/scsi/virtio_scsi.c
 @@ -198,7 +198,8 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
 unsigned int *p_idx,
   int i;

   for_each_sg(table-sgl, sg_elem, table-nents, i)
 - sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
 + sg_set_page(sg[idx++], sg_page(sg_elem), sg_elem-length,
 + sg_elem-offset);

 This can simply be

sg[idx++] = *sg_elem;


Yes, I saw your another E-mail. I think you're right. Simply calling
sg_set_page can not handle
the flag bits correctly. So, I'll repost the patch soon. Thank you!

 Can you repost it with this change, and also add sta...@vger.kernel.org
 to the Cc?  Thanks very much!

 Paolo
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Addr: XUPT,Xi'an,Shaanxi,China
Email: kelvin.x...@gmail.com
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Sen Wang
2012/7/25 Rolf Eike Beer eike-ker...@sf-tec.de:
 Am 25.07.2012 10:29, schrieb Wang Sen:

 When using the commands below to write some data to a virtio-scsi LUN of
 the
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu
 will crash.

 # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
 # sudo mount /dev/sdb /mnt
 # dd if=/dev/zero of=/mnt/file bs=1M count=1024

 In current implementation, sg_set_buf is called to add buffers to sg
 list which
 is put into the virtqueue eventually.


 The next sentence is somehow broken:


 But there are some HighMem pages in
 table-sgl can not get virtual address by sg_virt.


 Maybe something like But _if_ there are ... _you_ can not get ...?

Thanks, I'll pay attention in next post.


 Eike

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Addr: XUPT,Xi'an,Shaanxi,China
Email: kelvin.x...@gmail.com
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Sen Wang
2012/7/25 Stefan Hajnoczi stefa...@linux.vnet.ibm.com:
 On Wed, Jul 25, 2012 at 10:44:14AM +0200, Paolo Bonzini wrote:
 Il 25/07/2012 10:29, Wang Sen ha scritto:
  When using the commands below to write some data to a virtio-scsi LUN of 
  the
  QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
  crash.
 
  # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
  # sudo mount /dev/sdb /mnt
  # dd if=/dev/zero of=/mnt/file bs=1M count=1024
 
  In current implementation, sg_set_buf is called to add buffers to sg list 
  which
  is put into the virtqueue eventually. But there are some HighMem pages in
  table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
  return NULL value. This will cause QEMU exit when virtqueue_map_sg is 
  called
  in QEMU because an invalid GPA is passed by virtqueue.

 Heh, I was compiling (almost) the same patch as we speak. :)

 I've never seen QEMU crash; the VM would more likely just fail to boot
 with a panic.  But it's the same bug anyway.

 It's not a segfault crash, I think it hits an abort(3) in QEMU's
 virtio code when trying to map an invalid guest physical address.

How the guest boot fail? I never met this case.


 Stefan

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Addr: XUPT,Xi'an,Shaanxi,China
Email: kelvin.x...@gmail.com
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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Stefan Hajnoczi
On Tue, Jul 24, 2012 at 01:45:24PM -0700, Nicholas A. Bellinger wrote:
 On Mon, 2012-07-23 at 18:56 -0700, Greg Kroah-Hartman wrote:
  On Tue, Jul 24, 2012 at 01:26:20AM +, Nicholas A. Bellinger wrote:
   From: Nicholas Bellinger n...@linux-iscsi.org
   
   As requested by Anthony, here is a patch against 
   target-pending/for-next-merge
   to expose an ABI version to userspace via a new VHOST_SCSI_GET_ABI_VERSION
   ioctl operation.
   
   As mentioned in the comment, ABI Rev 0 is for pre 2012 out-of-tree code, 
   and
   ABI Rev 1 (the current rev) is for current WIP v3.6 kernel merge candiate 
   code.
   
   I think this is what you had in mind, and hopefully it will make MST 
   happy too.
   The incremental vhost-scsi patches against Zhi's QEMU are going out 
   shortly ahead
   of cutting a new vhost-scsi RFC over the next days.
   
   Please have a look and let me know if you have any concerns here.
   
   Thanks!
   
   Reported-by: Anthony Liguori aligu...@us.ibm.com
   Cc: Stefan Hajnoczi stefa...@linux.vnet.ibm.com
   Cc: Michael S. Tsirkin m...@redhat.com
   Cc: Paolo Bonzini pbonz...@redhat.com
   Cc: Zhi Yong Wu wu...@linux.vnet.ibm.com
   Signed-off-by: Nicholas Bellinger n...@linux-iscsi.org
   ---
drivers/vhost/tcm_vhost.c |9 +
drivers/vhost/tcm_vhost.h |   11 +++
2 files changed, 20 insertions(+), 0 deletions(-)
   
 
 SNIP
 
   diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
   index e942df9..3d5378f 100644
   --- a/drivers/vhost/tcm_vhost.h
   +++ b/drivers/vhost/tcm_vhost.h
   @@ -80,7 +80,17 @@ struct tcm_vhost_tport {

#include linux/vhost.h

   +/*
   + * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
   + *
   + * ABI Rev 0: All pre 2012 revisions used by prototype out-of-tree code
   + * ABI Rev 1: 2012 version for v3.6 kernel merge candiate
   + */
   +
   +#define VHOST_SCSI_ABI_VERSION   1
   +
struct vhost_scsi_target {
   + int abi_version;
 unsigned char vhost_wwpn[TRANSPORT_IQN_LEN];
 unsigned short vhost_tpgt;
};
   @@ -88,3 +98,4 @@ struct vhost_scsi_target {
/* VHOST_SCSI specific defines */
#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct 
   vhost_scsi_target)
#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct 
   vhost_scsi_target)
   +#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, struct 
   vhost_scsi_target)
  
  No, you just broke the ABI for version 0 here, that's not how you do
  this at all.
  
 
 The intention of this patch is use ABI=1 as a starting point for
 tcm_vhost moving forward, with no back-wards compat for the ABI=0
 prototype userspace code because:
 
 - It's based on a slightly older version of QEMU (updating the QEMU series 
 now)
 - It does not have an GET_ABI_VERSION ioctl cmd (that starts with ABI=1)
 - It has a small user-base of target + virtio-scsi developers
 
 So I did consider just starting from ABI=0, but figured this would help
 reduce the confusion for QEMU userspace wrt to the vhost-scsi code
 that's been floating around out-of-tree for the last 2 years.

There is no real user base beyond the handful of people who have hacked
on this.  Adding the GET_ABI_VERSION ioctl() at this stage is fine,
especially considering that the userspace code that talks to tcm_vhost
isn't in mainline in userspace yet either.

Stefan

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Re: [PATCH] sd: do not set changed flag on all unit attention conditions

2012-07-25 Thread Hannes Reinecke
On 07/17/2012 11:11 AM, James Bottomley wrote:
 On Tue, 2012-07-17 at 10:54 +0200, Paolo Bonzini wrote:
 Il 17/07/2012 10:40, James Bottomley ha scritto:

 It's not specific to virtio-scsi, in fact I expect that virtio-scsi will
 be almost always used with non-removable disks.

 However, QEMU's SCSI target is not used just for virtio-scsi (for
 example it can be used for USB storage), and it lets you mark a disk as
 removable---why? because there exists real hardware that presents itself
 as an SBC removable disk.  The only thing that is specific to
 virtualization, is support for online resizing (which generates a unit
 attention condition CAPACITY DATA HAS CHANGED).
 So what's the problem?  If you're doing pass through of a physical disk,
 we pick up removable from its inquiry string ... a physical removable
 device doesn't get resized.  If you have a virtual disk you want to
 resize, you don't set the removable flag in the inquiry data.

 In practice people will do what you said, and it's not a problem.

 However, there's nothing that prevents you from running qemu with a
 removable SCSI disk, and then resizing it.  I would like this to work,
 because SBC allows it and there's no reason why it shouldn't.
 
 There's no such thing in the market today as a removable disk that's
 resizeable.  Removable disks are for things like backup cartridges and
 ageing jazz drives.  Worse: most removeable devices today are USB card
 readers whose standards compliance varies from iffy to non existent.
 Resizeable disks are currently the province of storage arrays.
 
Ho-hum. I beg to disagree.

drivers/scsi/aacraid/aachba.c:2266

/* Do not cache partition table for arrays */
scsicmd-device-removable = 1;

To the extend of my knowledge aacraid does this _precisely_ to allow
for resizing; in effect every open() will trigger a device revalidation.

So I guess by just setting the 'removable' flag you should be okay.
You might need to remount it, but that's another story.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke   zSeries  Storage
h...@suse.de  +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)


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[PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Wang Sen
When using the commands below to write some data to a virtio-scsi LUN of the
QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.

# sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
# sudo mount /dev/sdb /mnt
# dd if=/dev/zero of=/mnt/file bs=1M count=1024

In current implementation, sg_set_buf is called to add buffers to sg list which
is put into the virtqueue eventually. But if there are some HighMem pages in
table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
in QEMU because an invalid GPA is passed by virtqueue.

I take Paolo's solution mentioned in last thread to avoid failure on handling 
flag bits.

I have tested the patch on my workstation. QEMU would not crash any more.

Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
---
 drivers/scsi/virtio_scsi.c |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 1b38431..6661610 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -198,7 +198,7 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
unsigned int *p_idx,
int i;
 
for_each_sg(table-sgl, sg_elem, table-nents, i)
-   sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
+   sg[idx++] = *sg_elem;
 
*p_idx = idx;
 }
-- 
1.7.9.5

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Re: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Ben Hutchings
On Wed, 2012-07-25 at 20:13 +0800, Wang Sen wrote:
 When using the commands below to write some data to a virtio-scsi LUN of the
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.
 
 # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
 # sudo mount /dev/sdb /mnt
 # dd if=/dev/zero of=/mnt/file bs=1M count=1024
 
 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But if there are some HighMem pages in
 table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) 
 may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
 in QEMU because an invalid GPA is passed by virtqueue.
 
 I take Paolo's solution mentioned in last thread to avoid failure on handling 
 flag bits.
 
 I have tested the patch on my workstation. QEMU would not crash any more.

 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
[...]

This is not the correct way to submit a change for stable.  See
Documentation/stable_kernel_rules.txt.

Ben.

-- 
Ben Hutchings
If more than one person is responsible for a bug, no one is at fault.


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Description: This is a digitally signed message part


Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 12:41 PM, Paolo Bonzini wrote:

 Il 25/07/2012 11:22, Boaz Harrosh ha scritto:
  for_each_sg(table-sgl, sg_elem, table-nents, i)
 -sg_set_buf(sg[idx++], sg_virt(sg_elem), 
 sg_elem-length);
 +sg_set_page(sg[idx++], sg_page(sg_elem), 
 sg_elem-length,
 +sg_elem-offset);

 This can simply be

sg[idx++] = *sg_elem;

 Can you repost it with this change, and also add sta...@vger.kernel.org
 to the Cc?  Thanks very much!


 No! Please use sg_set_page()! Look at sg_set_page(), which calls 
 sg_assign_page().
 It has all these jump over chained arrays. When you'll start using long
 sg_lists (which you should) then jumping from chain to chain must go through
 sg_page(sg_elem)  sg_assign_page(), As in the original patch.
 
 Hi Boaz,
 
 actually it seems to me that using sg_set_page is wrong, because it will
 not copy the end marker from table-sgl to sg[].  If something chained
 the sg[] scatterlist onto something else, sg_next's test for sg_is_last
 would go beyond the table-nents-th item and access invalid memory.
 


Yes, you did not understand this structure. And Yes I am right, when
using chained lists you *must* use sg_set_page().

You see the chaining belongs to the allocation not the value of the
sg-elements. One must not copy the chaining marker to the destination
array which might have it's own. And one must not crap all over the
destination chaining markers, set at allocation time.

The sizes and mostly the pointers of source and destination are not
the same.

 Using chained sglists is on my to-do list, I expect that it would make a
 nice performance improvement.  However, I was a bit confused as to
 what's the plan there; there is hardly any user, and many arches still
 do not define ARCH_HAS_SG_CHAIN.  Do you have any pointer to discussions
 or LWN articles?
 


Only the source code I'm afraid.

In SCSI land most LLDs should support chaining just by virtu of using the
for_each_sg macro. That all it takes. Your code above does support it.
(In Wang version).

Though more code need probably be added at sg allocation to actually
allocate and prepare a chain.

 I would need to add support for the long sglists to virtio; this is not
 a problem, but in the past Rusty complained that long sg-lists are not
 well suited to virtio (which would like to add elements not just at the
 beginning of a given sglist, but also at the end).  


Well that can be done as well, (If done carefully) It should be easy to add
chained fragments to both the end of a given chain just as at beginning.

It only means that the last element of the appended-to chain moves to
the next fragment and it's place is replaced by a link.

If you have ready made two long segments A and C which you would like not
to reallocate and copy, you insert a two-elements segment in the middle, say
call it B.

The first element of B is the last element of A which is now used as the pointer
to B, and the 2nd element of B is a pointer to C.

 It seems to me that
 virtio would prefer to work with a struct scatterlist ** rather than a
 long sglist.
 


That's just going backwards, and lazy. As you said if you want to enjoy
the better performance cake you better break some eggs ;-)

 Paolo


Cheers
Boaz
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 02:44 PM, Sen Wang wrote:

 2012/7/25 Paolo Bonzini pbonz...@redhat.com:
 Il 25/07/2012 10:29, Wang Sen ha scritto:
 When using the commands below to write some data to a virtio-scsi LUN of the
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
 crash.

   # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
   # sudo mount /dev/sdb /mnt
   # dd if=/dev/zero of=/mnt/file bs=1M count=1024

 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But there are some HighMem pages in
 table-sgl can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
 in QEMU because an invalid GPA is passed by virtqueue.

 Heh, I was compiling (almost) the same patch as we speak. :)
 
 Uh, what a coincidence! :)
 

 I've never seen QEMU crash; the VM would more likely just fail to boot
 with a panic.  But it's the same bug anyway.
 
 I never met this before. How this situation happens?
 

 My solution is using sg_set_page instead of sg_set_buf.

 I have tested the patch on my workstation. QEMU would not crash any more.

 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

 diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
 index 1b38431..fc5c88a 100644
 --- a/drivers/scsi/virtio_scsi.c
 +++ b/drivers/scsi/virtio_scsi.c
 @@ -198,7 +198,8 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
 unsigned int *p_idx,
   int i;

   for_each_sg(table-sgl, sg_elem, table-nents, i)
 - sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
 + sg_set_page(sg[idx++], sg_page(sg_elem), sg_elem-length,
 + sg_elem-offset);

 This can simply be

sg[idx++] = *sg_elem;

 
 Yes, I saw your another E-mail. I think you're right. Simply calling
 sg_set_page can not handle
 the flag bits correctly. So, I'll repost the patch soon. Thank you!
 


No this code is correct, though you will need to make sure to properly
terminate the destination sg_list.

But since old code was using sg_set_buf(), than it means it was properly
terminated before, and there for this code is good as is please don't
touch it.

Thanks
Boaz

 Can you repost it with this change, and also add sta...@vger.kernel.org
 to the Cc?  Thanks very much!

 Paolo
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Re: [PATCH v2] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 03:34 PM, Paolo Bonzini wrote:

 Il 25/07/2012 14:13, Wang Sen ha scritto:
 When using the commands below to write some data to a virtio-scsi LUN of the
 QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will 
 crash.

 # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
 # sudo mount /dev/sdb /mnt
 # dd if=/dev/zero of=/mnt/file bs=1M count=1024

 In current implementation, sg_set_buf is called to add buffers to sg list 
 which
 is put into the virtqueue eventually. But if there are some HighMem pages in
 table-sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) 
 may
 return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
 in QEMU because an invalid GPA is passed by virtqueue.

 I take Paolo's solution mentioned in last thread to avoid failure on 
 handling 
 flag bits.
 
 Please include an URL or (better) summarize the reason why sg_set_page
 is not correct in the commit message.  For example, replace this
 paragraph with the following:
 
 To fix this, we can simply copy the original scatterlist entries into
 virtio-scsi's; we need to copy the entries entirely, including the flag
 bits, so using sg_set_page is not correct.
 

 Please send v3 with this change and I'll add my Acked-by.
 


NACK-by: Boaz Harrosh


Apart from the HighMem pages problem, where in previous sg_set_buf()
code was the marker copied? It was not because it is not needed because
the allocation of sg took care of that. For example in 64bit the is no
bugs, right?

If there was a destination sg_list termination bug, it should be fixed
as a separate patch from this HighMem pages problem. But I bet if
you inspect the code carefully there isn't such a bug.

Cheers
Boaz

 Paolo
 

 I have tested the patch on my workstation. QEMU would not crash any more.

 Signed-off-by: Wang Sen senw...@linux.vnet.ibm.com
 ---
  drivers/scsi/virtio_scsi.c |2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

 diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
 index 1b38431..6661610 100644
 --- a/drivers/scsi/virtio_scsi.c
 +++ b/drivers/scsi/virtio_scsi.c
 @@ -198,7 +198,7 @@ static void virtscsi_map_sgl(struct scatterlist *sg, 
 unsigned int *p_idx,
  int i;
  
  for_each_sg(table-sgl, sg_elem, table-nents, i)
 -sg_set_buf(sg[idx++], sg_virt(sg_elem), sg_elem-length);
 +sg[idx++] = *sg_elem;
  
  *p_idx = idx;
  }

 
 
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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 14:34, Boaz Harrosh ha scritto:
 for_each_sg(table-sgl, sg_elem, table-nents, i)
 -   sg_set_buf(sg[idx++], sg_virt(sg_elem), 
 sg_elem-length);
 +   sg_set_page(sg[idx++], sg_page(sg_elem), 
 sg_elem-length,
 +   sg_elem-offset);

 This can simply be

sg[idx++] = *sg_elem;


 No! Please use sg_set_page()! Look at sg_set_page(), which calls 
 sg_assign_page().
 It has all these jump over chained arrays. When you'll start using long
 sg_lists (which you should) then jumping from chain to chain must go through
 sg_page(sg_elem)  sg_assign_page(), As in the original patch.

 actually it seems to me that using sg_set_page is wrong, because it will
 not copy the end marker from table-sgl to sg[].  If something chained
 the sg[] scatterlist onto something else, sg_next's test for sg_is_last
 would go beyond the table-nents-th item and access invalid memory.
 
 
 Yes, you did not understand this structure. And Yes I am right, when
 using chained lists you *must* use sg_set_page().
 
 You see the chaining belongs to the allocation not the value of the
 sg-elements. One must not copy the chaining marker to the destination
 array which might have it's own.

Except here the destination array has to be given to virtio, which
doesn't (yet) understand chaining.  I'm using for_each_sg rather than a
simple memcpy exactly because I want to flatten the input scatterlist
onto consecutive scatterlist entries, which is what virtio expects (and
what I'll change when I get to it).

for_each_sg guarantees that I get non-chain scatterlists only, so it is
okay to value-assign them to sg[].

(Replying to your other message,

 No this code is correct, though you will need to make sure to properly
 terminate the destination sg_list.
 
 But since old code was using sg_set_buf(), than it means it was properly
 terminated before, and there for this code is good as is please don't
 touch it.

It was _not_ properly terminated, and didn't matter because virtio
doesn't care about termination.  Changing all the virtio devices to
properly terminate chains (and to use for_each_sg) is a prerequisite for
properly supporting long sglists).

 In SCSI land most LLDs should support chaining just by virtu of using the
 for_each_sg macro. That all it takes. Your code above does support it.

Yes, it supports it but still has to undo them before passing to virtio.

What my LLD does is add a request descriptor in front of the scatterlist
that the LLD receives.  I would like to do this with a 2-item
scatterlist: one for the request descriptor, and one which is a chain to
the original scatterlist.  Except that if I call sg_chain and my
architecture does not define ARCH_HAS_SG_CHAIN, it will BUG out.  So I
need to keep all the scatterlist allocation and copying crap that I have
now within #ifdef, and it will bitrot.

 I would need to add support for the long sglists to virtio; this is not
 a problem, but in the past Rusty complained that long sg-lists are not
 well suited to virtio (which would like to add elements not just at the
 beginning of a given sglist, but also at the end).  
 
 Well that can be done as well, (If done carefully) It should be easy to add
 chained fragments to both the end of a given chain just as at beginning.
 It only means that the last element of the appended-to chain moves to
 the next fragment and it's place is replaced by a link.

But you cannot do that in constant time, can you?  And that means you do
not enjoy any benefit in terms of cache misses etc.

Also, this assumes that I can modify the appended-to chain.  I'm not
sure I can do this?

 It seems to me that virtio would prefer to work with a struct
 scatterlist ** rather than a long sglist.
 
 That's just going backwards, and lazy. As you said if you want to enjoy
 the better performance cake you better break some eggs ;-)

:)

Paolo
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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Avi Kivity
On 07/24/2012 11:45 PM, Nicholas A. Bellinger wrote:

  diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
  index e942df9..3d5378f 100644
  --- a/drivers/vhost/tcm_vhost.h
  +++ b/drivers/vhost/tcm_vhost.h
  @@ -80,7 +80,17 @@ struct tcm_vhost_tport {
   
   #include linux/vhost.h
   
  +/*
  + * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
  + *
  + * ABI Rev 0: All pre 2012 revisions used by prototype out-of-tree code
  + * ABI Rev 1: 2012 version for v3.6 kernel merge candiate
  + */


If it's out of tree, why consider it at all?  Put a stable ABI in tree
and extend it in compatible ways.


-- 
error compiling committee.c: too many arguments to function


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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 03:49 PM, Paolo Bonzini wrote:

 
 Except here the destination array has to be given to virtio, which
 doesn't (yet) understand chaining.  I'm using for_each_sg rather than a
 simple memcpy exactly because I want to flatten the input scatterlist
 onto consecutive scatterlist entries, which is what virtio expects (and
 what I'll change when I get to it).
 
 for_each_sg guarantees that I get non-chain scatterlists only, so it is
 okay to value-assign them to sg[].
 


So if the virtio does not understand chaining at all then surly it will
not understand the 2-bit end marker and will get a wrong page pointer
with the 1st bit set.

As I said!! Since the last code did sg_set_buff() and worked then you must
change it with sg_set_page().

If there are *any* chaining-or-no-chaining markers errors these should
be fixed as a separate patch!

Please lets concentrate at the problem at hand.

snip

 
 It was _not_ properly terminated, and didn't matter because virtio
 doesn't care about termination.  Changing all the virtio devices to
 properly terminate chains (and to use for_each_sg) is a prerequisite for
 properly supporting long sglists).
 


Fine then your code is now a crash because the terminating bit was just
copied over, which it was not before.


Now Back to the how to support chaining:

Lets separate the two topics from now on. Send me one mail concerning
the proper above patch, And a different mail for how to support chaining.

 In SCSI land most LLDs should support chaining just by virtu of using the
 for_each_sg macro. That all it takes. Your code above does support it.
 
 Yes, it supports it but still has to undo them before passing to virtio.
 
 What my LLD does is add a request descriptor in front of the scatterlist
 that the LLD receives.  I would like to do this with a 2-item
 scatterlist: one for the request descriptor, and one which is a chain to
 the original scatterlist.  


I hate that plan. Why yet override the scatter element yet again with a third
union of a request descriptor

The reason it was overloaded as a link-pointer in the first place was because
of historical compatibility reasons and not because of a good design.

You should have a proper request descriptor structure defined, pointing to
(or followed by), an sglist-chain. And all of the above is mute.
 

 Except that if I call sg_chain and my
 architecture does not define ARCH_HAS_SG_CHAIN, it will BUG out.  So I
 need to keep all the scatterlist allocation and copying crap that I have
 now within #ifdef, and it will bitrot.
 


except that with the correct design you don't call sg_chain you just do:
request_descriptor-sg_list = sg;

 I would need to add support for the long sglists to virtio; this is not
 a problem, but in the past Rusty complained that long sg-lists are not
 well suited to virtio (which would like to add elements not just at the
 beginning of a given sglist, but also at the end).  

 Well that can be done as well, (If done carefully) It should be easy to add
 chained fragments to both the end of a given chain just as at beginning.
 It only means that the last element of the appended-to chain moves to
 the next fragment and it's place is replaced by a link.
 
 But you cannot do that in constant time, can you?  And that means you do
 not enjoy any benefit in terms of cache misses etc.
 


I did not understand constant time it is O(0) if that what you meant.

(And surly today's code of copy the full list cache misses)

 Also, this assumes that I can modify the appended-to chain.  I'm not
 sure I can do this?
 


Each case it's own. If the appended-to chain is const, yes you'll have
to reallocate it and copy. Is that your case?

Cheers
Boaz

 It seems to me that virtio would prefer to work with a struct
 scatterlist ** rather than a long sglist.

 That's just going backwards, and lazy. As you said if you want to enjoy
 the better performance cake you better break some eggs ;-)
 
 :)
 
 Paolo


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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 15:26, Boaz Harrosh ha scritto:
 On 07/25/2012 03:49 PM, Paolo Bonzini wrote:
 

 Except here the destination array has to be given to virtio, which
 doesn't (yet) understand chaining.  I'm using for_each_sg rather than a
 simple memcpy exactly because I want to flatten the input scatterlist
 onto consecutive scatterlist entries, which is what virtio expects (and
 what I'll change when I get to it).

 for_each_sg guarantees that I get non-chain scatterlists only, so it is
 okay to value-assign them to sg[].
 
 So if the virtio does not understand chaining at all then surly it will
 not understand the 2-bit end marker and will get a wrong page pointer
 with the 1st bit set.

It doesn't understand chaining, but it does use sg_phys(x) so it will
not get a wrong page pointer for the end marker.

 Fine then your code is now a crash because the terminating bit was just
 copied over, which it was not before.

I did test the patch with value-assignment.

 Lets separate the two topics from now on. Send me one mail concerning
 the proper above patch, And a different mail for how to support chaining.

Ok, and I'll change the topic.

Paolo
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virtio(-scsi) vs. chained sg_lists (was Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list)

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 15:26, Boaz Harrosh ha scritto:
 In SCSI land most LLDs should support chaining just by virtu of using the
 for_each_sg macro. That all it takes. Your code above does support it.

 Yes, it supports it but still has to undo them before passing to virtio.

 What my LLD does is add a request descriptor in front of the scatterlist
 that the LLD receives.  I would like to do this with a 2-item
 scatterlist: one for the request descriptor, and one which is a chain to
 the original scatterlist.  
 
 I hate that plan. Why yet override the scatter element yet again with a third
 union of a request descriptor

I'm not overriding (or did you mean overloading?) anything, and I think
you're reading too much in my words.

What I am saying is (for a WRITE command):

1) what I get is a scsi_cmnd which contains an N-element scatterlist.

2) virtio-scsi has to build the packet that is passed to the hardware
(it does not matter that the hardware is virtual).  This packet (per
virtio-scsi spec) has an N+1-element scatterlist, where the first
element is a request descriptor (struct virtio_scsi_cmd_req), and the
others describe the written data.

3) virtio takes care of converting the packet from a scatterlist
(which currently must be a flat one) to the hardware representation.
Here a walk is inevitable, so we don't care about this walk.

4) What I'm doing now: copying (and flattening) the N-element
scatterlist onto the last elements of an N+1 array that I pass to virtio.

  _ _ _ _ _ _
 |_|_|_|_|_|_|  scsi_cmnd scatterlist

 vvv COPY vvv
_ _ _ _ _ _ _
   |_|_|_|_|_|_|_|  scatterlist passed to virtio
|
virtio_scsi_cmd_req

Then I hand off the scatterlist to virtio.  virtio walks it and converts
it to hardware format.

5) What I want to do: create a 2-element scatterlist, the first being
the request descriptor and the second chaining to scsi_cmnd's N-element
scatterlist.

 _ _ _ _ _ _
|_|_|_|_|_|_|  scsi_cmnd scatterlist
_ _/
   |_|C|   scatterlist passed to virtio
|
virtio_scsi_cmd_req

Then I hand off the scatterlist to virtio.  virtio will still walk the
scatterlist chain, and convert it to N+1 elements for the hardware to
consume.  Still, removing one walk largely reduces the length of my
critical sections.  I also save some pointer-chasing because the
2-element scatterlist are short-lived and can reside on the stack.


Other details (you can probably skip these):

There is also a response descriptor.  In the case of writes this is the
only element that the hardware will write to, so in the case of writes
the written by hardware scatterlist has 1 element only and does not
need chaining.

Reads are entirely symmetric.  The hardware will read the request
descriptor from a 1-element scatterlist, and will write response+data
into an N+1-element scatterlist (the response descriptor precedes the
data that was read).  It can be treated in exactly the same way.  The
N+1-element scatterlist could also become a 2-element scatterlist with
chaining.

 Except that if I call sg_chain and my
 architecture does not define ARCH_HAS_SG_CHAIN, it will BUG out.  So I
 need to keep all the scatterlist allocation and copying crap that I have
 now within #ifdef, and it will bitrot.
 
 except that with the correct design you don't call sg_chain you just do:
   request_descriptor-sg_list = sg;

By the above it should be clear, that request_descriptor is not a
driver-private extension of the scsi_cmnd.  It is something passed to
the hardware.

 Well that can be done as well, (If done carefully) It should be easy to add
 chained fragments to both the end of a given chain just as at beginning.
 It only means that the last element of the appended-to chain moves to
 the next fragment and it's place is replaced by a link.

 But you cannot do that in constant time, can you?  And that means you do
 not enjoy any benefit in terms of cache misses etc.
 
 I did not understand constant time it is O(0) if that what you meant.

In the worst case it is a linked list, no?  So in the worst case
_finding_ the last element of the appended-to chain is O(n).

Actually, appending to the end is not a problem for virtio-scsi.  But
for example the virtio-blk spec places the response descriptor _after_
the input data.  I think this was a mistake, and I didn't repeat it for
virtio-scsi, but I cited it because in the past Rusty complained that
the long sglist implementation was SCSI-centric.

 Also, this assumes that I can modify the appended-to chain.  I'm not
 sure I can do this?
 
 Each case it's own. If the appended-to chain is const, yes you'll have
 to reallocate it and copy. Is that your case?

It will be virtio-blk's case, but we can ignore it.

Paolo
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Re: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread James Bottomley
On Sun, 2012-07-22 at 10:31 -0700, Tejun Heo wrote:
 Hello,
 
 On Sat, Jul 21, 2012 at 02:15:56PM +0200, Matthias Prager wrote:
  Now I'm not sure this isn't taping over another bug. Which leads me to
  my question: What is the correct behavior?
  
  #1 Issuing a separate spin-up command (START UNIT?) prior to sending i/o
  by setting allow_restart=1 for sata disks on sas controllers
  
  or
  
  #2 Teaching the sas drivers they do not need spin-up commands and can
  simply start issuing i/o to sata disks
 
 I haven't consulted SAT but it seems like a bug in SAS driver or
 firmware.  If it's a driver bug, we better fix it there.  If a
 firmware bug, working around those is one of major roles of drivers,
 so I think setting allow_restart is fine.

Actually, I don't think so.  SAT-2 section 8.12.2 does say 

if the device is in the stopped state as the result of
processing a START STOP UNIT command (see 9.11), then the SATL
shall terminate the TEST UNIT READY command with CHECK CONDITION
status with the sense key set to NOT READY and the additional
sense code of LOGICAL UNIT NOT READY, INITIALIZING COMMAND
REQUIRED;

START STOP UNIT (with START=0) translates to STANDBY IMMEDIATE, and
that's what hdparm -y issues.  We don't see this in /drivers/ata because
TEST UNIT READY always returns success.

So it looks like the mpt2sas SAT is doing the correct thing and we only
don't see this problem in normal SATA devices because of a bug in the
libata-scsi SAT.

However, the kernel log

Apr 04 22:55:10 [kernel] sd 1:0:1:0: [sdj] Device not ready
Apr 04 22:55:10 [kernel] sd 1:0:1:0: [sdj]  Result: hostbyte=DID_OK 
driverbyte=DRIVER_SENSE
Apr 04 22:55:10 [kernel] sd 1:0:1:0: [sdj]  Sense Key : Not Ready [current]
Apr 04 22:55:10 [kernel] sd 1:0:1:0: [sdj]  Add. Sense: Logical unit not ready, 
initializing command required
Apr 04 22:55:10 [kernel] sd 1:0:1:0: [sdj] CDB: Write(10): 2a 00 57 54 52 3f 00 
00 08 00

Indicates we got the NOT READY to a non-TUR command, so I suspect what's
happening is that sending the TUR causes the SAT to remember the standby
state and respond NOT READY to all subsequent commands.  However, if we
just send an ordinary command, not a TUR, it quietly wakes the drive and
we don't see any problems.

There is support in SAT for this behaviour because there's a note on the
START STOP UNIT command saying

After returning GOOD status for a START STOP UNIT command with
the START bit set to zero, the SATL shall consider the ATA
device to be in the Stopped power state (see SBC-2)

Which in SCSI terms would mean return NOT READY to any subsequent
commands.

Can someone verify this is indeed what the mpt2sas HBA is doing?

James


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Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 04:36 PM, Paolo Bonzini wrote:

 Il 25/07/2012 15:26, Boaz Harrosh ha scritto:
 On 07/25/2012 03:49 PM, Paolo Bonzini wrote:


 Except here the destination array has to be given to virtio, which
 doesn't (yet) understand chaining.  I'm using for_each_sg rather than a
 simple memcpy exactly because I want to flatten the input scatterlist
 onto consecutive scatterlist entries, which is what virtio expects (and
 what I'll change when I get to it).

 for_each_sg guarantees that I get non-chain scatterlists only, so it is
 okay to value-assign them to sg[].

 So if the virtio does not understand chaining at all then surly it will
 not understand the 2-bit end marker and will get a wrong page pointer
 with the 1st bit set.
 
 It doesn't understand chaining, but it does use sg_phys(x) so it will
 not get a wrong page pointer for the end marker.
 
 Fine then your code is now a crash because the terminating bit was just
 copied over, which it was not before.
 
 I did test the patch with value-assignment.
 


Still you should use the sg_set_page()!!
1. It is not allowed to directly manipulate sg entries. One should always
   use the proper accessor. Even if open coding does work and is not a bug
   it should not be used anyway!
2. Future code that will support chaining will need to do as I say so why
   change it then, again?

Please don't change two things in one patch. The fix is for high-pages
please fix only that here. You can blasphemy open-code the sg manipulation
in a separate patch.

Please
Boaz

 Lets separate the two topics from now on. Send me one mail concerning
 the proper above patch, And a different mail for how to support chaining.
 
 Ok, and I'll change the topic.
 
 Paolo


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performance improvements for the sglist API (Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list)

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 16:36, Boaz Harrosh ha scritto:
  
  I did test the patch with value-assignment.
  
 
 Still you should use the sg_set_page()!!
 1. It is not allowed to directly manipulate sg entries. One should always
use the proper accessor. Even if open coding does work and is not a bug
it should not be used anyway!
 2. Future code that will support chaining will need to do as I say so why
change it then, again?

Future code that will support chaining will not copy anything at all.

Also, and more important, note that I am _not_ calling sg_init_table
before the loop, only once in the driver initialization.  That's because
memset in sg_init_table is an absolute performance killer, especially if
you have to do it in a critical section; and I'm not making this up, see
blk_rq_map_sg:

  * If the driver previously mapped a shorter
  * list, we could see a termination bit
  * prematurely unless it fully inits the sg
  * table on each mapping. We KNOW that there
  * must be more entries here or the driver
  * would be buggy, so force clear the
  * termination bit to avoid doing a full
  * sg_init_table() in drivers for each command.
  */
  sg-page_link = ~0x02;
  sg = sg_next(sg);

So let's instead fix the API so that I (and blk-merge.c) can touch
memory just once.  For example you could add __sg_set_page and
__sg_set_buf, basically the equivalent of

memset(sg, 0, sizeof(*sg));
sg_set_{page,buf}(sg, page, len, offset);

Calling these functions would be fine if you later add a manual call to
sg_mark_end, again the same as blk-merge.c does.  See the attached
untested/uncompiled patch.

And value assignment would be the same as a

__sg_set_page(sg, sg_page(page), sg-length, sg-offset);

 Please don't change two things in one patch. The fix is for high-pages
 please fix only that here. You can blasphemy open-code the sg manipulation
 in a separate patch.

The blasphemy is already there (the scatterlist that is handed to virtio
won't have the right end-of-chain marker).  If anything,
value-assignment is trading a subtle blasphemy for a blatant one.
That's already an improvement, but let's just fix the API instead.

Paolo
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Re: performance improvements for the sglist API (Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list)

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 17:09, Paolo Bonzini ha scritto:
 Il 25/07/2012 16:36, Boaz Harrosh ha scritto:

 I did test the patch with value-assignment.


 Still you should use the sg_set_page()!!
 1. It is not allowed to directly manipulate sg entries. One should always
use the proper accessor. Even if open coding does work and is not a bug
it should not be used anyway!
 2. Future code that will support chaining will need to do as I say so why
change it then, again?
 
 Future code that will support chaining will not copy anything at all.
 
 Also, and more important, note that I am _not_ calling sg_init_table
 before the loop, only once in the driver initialization.  That's because
 memset in sg_init_table is an absolute performance killer, especially if
 you have to do it in a critical section; and I'm not making this up, see
 blk_rq_map_sg:
 
   * If the driver previously mapped a shorter
   * list, we could see a termination bit
   * prematurely unless it fully inits the sg
   * table on each mapping. We KNOW that there
   * must be more entries here or the driver
   * would be buggy, so force clear the
   * termination bit to avoid doing a full
   * sg_init_table() in drivers for each command.
   */
   sg-page_link = ~0x02;
   sg = sg_next(sg);
 
 So let's instead fix the API so that I (and blk-merge.c) can touch
 memory just once.  For example you could add __sg_set_page and
 __sg_set_buf, basically the equivalent of
 
 memset(sg, 0, sizeof(*sg));
 sg_set_{page,buf}(sg, page, len, offset);
 
 Calling these functions would be fine if you later add a manual call to
 sg_mark_end, again the same as blk-merge.c does.  See the attached
 untested/uncompiled patch.
 
 And value assignment would be the same as a
 
 __sg_set_page(sg, sg_page(page), sg-length, sg-offset);

ENOPATCH...

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 160035f..00ba3d4 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -146,7 +146,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request 
*rq,
 new_segment:
if (!sg)
sg = sglist;
-   else {
+   else
+   sg = sg_next(sg);
+
/*
 * If the driver previously mapped a shorter
 * list, we could see a termination bit
@@ -158,11 +160,7 @@ new_segment:
 * termination bit to avoid doing a full
 * sg_init_table() in drivers for each command.
 */
-   sg-page_link = ~0x02;
-   sg = sg_next(sg);
-   }
-
-   sg_set_page(sg, bvec-bv_page, nbytes, bvec-bv_offset);
+   __sg_set_page(sg, bvec-bv_page, nbytes, 
bvec-bv_offset);
nsegs++;
}
bvprv = bvec;
@@ -182,12 +180,11 @@ new_segment:
if (rq-cmd_flags  REQ_WRITE)
memset(q-dma_drain_buffer, 0, q-dma_drain_size);
 
-   sg-page_link = ~0x02;
sg = sg_next(sg);
-   sg_set_page(sg, virt_to_page(q-dma_drain_buffer),
-   q-dma_drain_size,
-   ((unsigned long)q-dma_drain_buffer) 
-   (PAGE_SIZE - 1));
+   __sg_set_page(sg, virt_to_page(q-dma_drain_buffer),
+ q-dma_drain_size,
+ ((unsigned long)q-dma_drain_buffer) 
+ (PAGE_SIZE - 1));
nsegs++;
rq-extra_len += q-dma_drain_size;
}
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index ac9586d..d6a937e 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -44,32 +44,23 @@ struct sg_table {
 #define sg_chain_ptr(sg)   \
((struct scatterlist *) ((sg)-page_link  ~0x03))
 
-/**
- * sg_assign_page - Assign a given page to an SG entry
- * @sg:SG entry
- * @page:  The page
- *
- * Description:
- *   Assign page to sg entry. Also see sg_set_page(), the most commonly used
- *   variant.
- *
- **/
-static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
+static inline void __sg_set_page(struct scatterlist *sg, struct page *page,
+unsigned int len, unsigned int offset)
 {
-   unsigned long page_link = sg-page_link  0x3;
-
/*
 * In order for the low bit stealing approach to work, pages
 * must be aligned at a 

Question about releasing buffers allocated to request-special

2012-07-25 Thread Aniket Kulkarni

Hello

I have a setup with a 12 daisy chained EXP3000 enclosures connected to
a server such that each of the disks are accessible via two paths
through multiple sas expanders. The server has 2 dual ported HBAs. I'm
running 2.6.32 kernel variant based on RHEL 6.0. I have seen this on
2.6.31 as well.

I am seeing a bunch of kernel panics pretty frequently with an
interesting pattern -

The kernel paniced trying to deference stuff from scsi_cmnd passed to  
scsi_dispatch_cmd. Looking at its caller


scsi_request_fn(request_queue *q)
device = q-quedata;
req = get_request_from_queue(q);

cmd = req-special;
if (!cmd)
return;

scsi_dispatch_cmd(cmd);

The interesting thing is cmd-device != device; they should've been  
the same. In fact it looks like req-special itself is garbage and  
that's why we have been looking at the wrong stuff in  
scsi_dispatch_cmd. It also explains why we can find the device on  
upper frames and prove that it (and all its attributes) are healthy  
all the way from MD to LSI.


The only place in scsi layer that frees req-special is

scsi_prep_return()

case BLKPREP_KILL:
req-errors = DID_NO_CONNECT  16;
/* release the command and kill it */
if (req-special) {
struct scsi_cmnd *cmd = req-special;   --
scsi_release_buffers(cmd);|__ not atomic
scsi_put_command(cmd);|
req-special = NULL;--
}

I know this is a basic question, but I'm wondering how does one  
prevent threads from using req-special while its being deallocated  
here? I see checks for special == NULL at a lot of places but the  
release and reset of pointer (above) are not atomic.


Thanks in advance.
--
Aniket Kulkarni


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Re: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread Tejun Heo
Hello, James.

On Wed, Jul 25, 2012 at 06:19:13PM +0400, James Bottomley wrote:
  I haven't consulted SAT but it seems like a bug in SAS driver or
  firmware.  If it's a driver bug, we better fix it there.  If a
  firmware bug, working around those is one of major roles of drivers,
  so I think setting allow_restart is fine.
 
 Actually, I don't think so.  SAT-2 section 8.12.2 does say 
 
 if the device is in the stopped state as the result of
 processing a START STOP UNIT command (see 9.11), then the SATL
 shall terminate the TEST UNIT READY command with CHECK CONDITION
 status with the sense key set to NOT READY and the additional
 sense code of LOGICAL UNIT NOT READY, INITIALIZING COMMAND
 REQUIRED;
 
 START STOP UNIT (with START=0) translates to STANDBY IMMEDIATE, and
 that's what hdparm -y issues.  We don't see this in /drivers/ata because
 TEST UNIT READY always returns success.

Urgh... ATA device in standby mode is ready for any command and
definitely doesn't need an initializing command.  Oh, well...

 So it looks like the mpt2sas SAT is doing the correct thing and we only
 don't see this problem in normal SATA devices because of a bug in the
 libata-scsi SAT.

libata is inconsistent with the standard but I think the standard is
wrong here. :(

Thanks.

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Re: virtio(-scsi) vs. chained sg_lists (was Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list)

2012-07-25 Thread Paolo Bonzini
Il 25/07/2012 17:28, Boaz Harrosh ha scritto:
 1) what I get is a scsi_cmnd which contains an N-element scatterlist.

 2) virtio-scsi has to build the packet that is passed to the hardware
 (it does not matter that the hardware is virtual).  This packet (per
 virtio-scsi spec) has an N+1-element scatterlist, where the first
 element is a request descriptor (struct virtio_scsi_cmd_req), and the
 others describe the written data.
 
 Then virtio-scsi spec is crap. It overloads the meaning of
 struct scatterlist of the first element in an array. to be a
 struct virtio_scsi_cmd_req.

What the holy fuck?  The first element simply _points_ to the struct
virtio_scsi_cmd_req, just like subsequent elements point to the data.

And the protocol of the device is _not_ a struct scatterlist[].  The
virtio _API_ takes that array and converts to a series of physical
address + offset pairs.

 Since you need to change the standard to support chaining then
 it is a good time to fix this.

Perhaps it is a good time for you to read the virtio spec.  You are
making a huge confusion between the LLD-virtio interface and the
virtio-hardware interface.  I'm talking only of the former.

 3) virtio takes care of converting the packet from a scatterlist
 (which currently must be a flat one) to the hardware representation.
 Here a walk is inevitable, so we don't care about this walk.
 
 hardware representation you mean aio or biovec, what ever the
 IO submission path uses at the host end?

No, I mean the way the virtio spec encodes the physical address + offset
pairs.

I stopped reading here.

Paolo
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[RESEND PATCH] SCSI: scsi_lib: fix scsi_io_completion's SG_IO error propagation

2012-07-25 Thread Mike Snitzer
The following v3.4-rc1 commit unmasked an existing bug in
scsi_io_completion's SG_IO error handling:
47ac56d [SCSI] scsi_error: classify some ILLEGAL_REQUEST sense as a permanent 
TARGET_ERROR

Given that certain ILLEGAL_REQUEST are now properly categorized as
TARGET_ERROR the host_byte is being set (before host_byte wasn't ever
set for these ILLEGAL_REQUEST).

In scsi_io_completion, initialize req-errors with cmd-result _after_
the SG_IO block that calls __scsi_error_from_host_byte (which may
modify the host_byte).

Before this fix:

cdb to send: 12 01 01 00 00 00
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[12, 01, 01, 00, 00, 00],
mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=2, flags=0,
status=02, masked_status=01, sb[19]=[70, 00, 05, 00, 00, 00, 00, 0b,
00, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00], host_status=0x10,
driver_status=0x8, resid=0, duration=0, info=0x1}) = 0
SCSI Status: Check Condition

Sense Information:
sense buffer empty

After:

cdb to send: 12 01 01 00 00 00
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[12, 01, 01, 00, 00, 00],
mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=2, flags=0,
status=02, masked_status=01, sb[19]=[70, 00, 05, 00, 00, 00, 00, 0b,
00, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00], host_status=0,
driver_status=0x8, resid=0, duration=0, info=0x1}) = 0
SCSI Status: Check Condition

Sense Information:
 Fixed format, current;  Sense key: Illegal Request
 Additional sense: Invalid field in cdb
 Raw sense data (in hex):
70 00 05 00 00 00 00 0b  00 00 00 00 24 00 00 00
00 00 00

Signed-off-by: Mike Snitzer snit...@redhat.com
Reported-by: Paolo Bonzini pbonz...@redhat.com
Tested-by: Paolo Bonzini pbonz...@redhat.com
Reviewed-by: Babu Moger babu.mo...@netapp.com
Cc: sta...@vger.kernel.org [v3.4+]
---
 drivers/scsi/scsi_lib.c |5 -
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b583277..9377ed2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -759,7 +759,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int 
good_bytes)
}
 
if (req-cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block 
level */
-   req-errors = result;
if (result) {
if (sense_valid  req-sense) {
/*
@@ -775,6 +774,10 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned 
int good_bytes)
if (!sense_deferred)
error = __scsi_error_from_host_byte(cmd, 
result);
}
+   /*
+* __scsi_error_from_host_byte may have reset the host_byte
+*/
+   req-errors = cmd-result;
 
req-resid_len = scsi_get_resid(cmd);
 
-- 
1.7.4.4

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Re: [resend PATCH 5/5] libsas, ipr: cleanup ata_host flags initialization via ata_host_init

2012-07-25 Thread Jeff Garzik

On 07/10/2012 12:06 AM, Dan Williams wrote:

libsas and ipr pass flags to ata_host_init that are meant for the port.

ata_host flags:
ATA_HOST_SIMPLEX= (1  0),   /* Host is simplex, one DMA 
channel per host only */
ATA_HOST_STARTED= (1  1),   /* Host started */
ATA_HOST_PARALLEL_SCAN  = (1  2),   /* Ports on this host can be 
scanned in parallel */
ATA_HOST_IGNORE_ATA = (1  3),   /* Ignore ATA devices on this 
host. */

flags passed by libsas:
ATA_FLAG_SATA   = (1  1),
ATA_FLAG_PIO_DMA= (1  7), /* PIO cmds via DMA */
ATA_FLAG_NCQ= (1  10), /* host supports NCQ */

The only one that aliases is ATA_HOST_STARTED which is a 'don't care' in
the libsas and ipr cases since ata_hosts from these sources are not
registered with libata.

Cc: Brian King brk...@us.ibm.com
Reported-by: Hannes Reinecke h...@suse.com
Signed-off-by: Dan Williams dan.j.willi...@intel.com
---
  drivers/ata/libata-core.c |   10 ++
  drivers/scsi/ipr.c|3 +--
  drivers/scsi/libsas/sas_ata.c |5 +
  include/linux/libata.h|3 +--


Acked-by: Jeff Garzik jgar...@redhat.com




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Re: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread James Bottomley
On Wed, 2012-07-25 at 10:17 -0700, Tejun Heo wrote:
 Hello, James.
 
 On Wed, Jul 25, 2012 at 06:19:13PM +0400, James Bottomley wrote:
   I haven't consulted SAT but it seems like a bug in SAS driver or
   firmware.  If it's a driver bug, we better fix it there.  If a
   firmware bug, working around those is one of major roles of drivers,
   so I think setting allow_restart is fine.
  
  Actually, I don't think so.  SAT-2 section 8.12.2 does say 
  
  if the device is in the stopped state as the result of
  processing a START STOP UNIT command (see 9.11), then the SATL
  shall terminate the TEST UNIT READY command with CHECK CONDITION
  status with the sense key set to NOT READY and the additional
  sense code of LOGICAL UNIT NOT READY, INITIALIZING COMMAND
  REQUIRED;
  
  START STOP UNIT (with START=0) translates to STANDBY IMMEDIATE, and
  that's what hdparm -y issues.  We don't see this in /drivers/ata because
  TEST UNIT READY always returns success.
 
 Urgh... ATA device in standby mode is ready for any command and
 definitely doesn't need an initializing command.  Oh, well...

Well, it does in sleep mode ... which seems to most closely map to what
SCSI thinks of as a stopped unit. I checked the specs just in case there
was an error ... they all say STANDBY not SLEEP.

  So it looks like the mpt2sas SAT is doing the correct thing and we only
  don't see this problem in normal SATA devices because of a bug in the
  libata-scsi SAT.
 
 libata is inconsistent with the standard but I think the standard is
 wrong here. :(

Well, reading it, so do I.  Unfortunately, we get to deal with the world
as it is rather than as we would wish it to be.  We likely have this
problem with a lot of USB SATLs as well ...

It looks like a hack like this might be needed.

James

---

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 4a6381c..7e59a7f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -42,6 +42,8 @@
 
 #include trace/events/scsi.h
 
+static void scsi_eh_done(struct scsi_cmnd *scmd);
+
 #define SENSE_TIMEOUT  (10*HZ)
 
 /*
@@ -241,6 +243,14 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
if (! scsi_command_normalize_sense(scmd, sshdr))
return FAILED;  /* no valid sense data */
 
+   if (scmd-cmnd[0] == TEST_UNIT_READY  scmd-scsi_done != scsi_eh_done)
+   /* 
+* nasty: for mid-layer issued TURs, we need to return the
+* actual sense data without any recovery attempt.  For eh
+* issued ones, we need to try to recover and interpret
+*/
+   return SUCCESS;
+
if (scsi_sense_is_deferred(sshdr))
return NEEDS_RETRY;
 
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 56a9379..91d3366 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -764,6 +764,16 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned 
char *inq_result,
sdev-model = (char *) (sdev-inquiry + 16);
sdev-rev = (char *) (sdev-inquiry + 32);
 
+   if (strncmp(sdev-vendor, ATA , 8) == 0) {
+   /* 
+* sata emulation layer device.  This is a hack to work around
+* the SATL power management specifications which state that
+* when the SATL detects the device has gone into standby
+* mode, it shall respond with NOT READY.
+*/
+   sdev-allow_restart = 1;
+   }
+
if (*bflags  BLIST_ISROM) {
sdev-type = TYPE_ROM;
sdev-removable = 1;


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Re: [resend PATCH 5/5] libsas, ipr: cleanup ata_host flags initialization via ata_host_init

2012-07-25 Thread Brian King
On 07/09/2012 11:06 PM, Dan Williams wrote:
 libsas and ipr pass flags to ata_host_init that are meant for the port.
 
 ata_host flags:
   ATA_HOST_SIMPLEX= (1  0), /* Host is simplex, one DMA 
 channel per host only */
   ATA_HOST_STARTED= (1  1), /* Host started */
   ATA_HOST_PARALLEL_SCAN  = (1  2), /* Ports on this host can be 
 scanned in parallel */
   ATA_HOST_IGNORE_ATA = (1  3), /* Ignore ATA devices on this 
 host. */
 
 flags passed by libsas:
   ATA_FLAG_SATA   = (1  1),
   ATA_FLAG_PIO_DMA= (1  7), /* PIO cmds via DMA */
   ATA_FLAG_NCQ= (1  10), /* host supports NCQ */
 
 The only one that aliases is ATA_HOST_STARTED which is a 'don't care' in
 the libsas and ipr cases since ata_hosts from these sources are not
 registered with libata.
 
 Cc: Brian King brk...@us.ibm.com
 Reported-by: Hannes Reinecke h...@suse.com
 Signed-off-by: Dan Williams dan.j.willi...@intel.com
 ---
  drivers/ata/libata-core.c |   10 ++
  drivers/scsi/ipr.c|3 +--
  drivers/scsi/libsas/sas_ata.c |5 +
  include/linux/libata.h|3 +--

Acked-by: Brian King brk...@linux.vnet.ibm.com

-- 
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Power Linux I/O
IBM Linux Technology Center




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Re: [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd

2012-07-25 Thread Jörn Engel
On Tue, 24 July 2012 09:01:41 +0400, James Bottomley wrote:
 On Mon, 2012-07-23 at 15:24 -0400, Jörn Engel wrote:
  On Mon, 23 July 2012 23:45:55 +0400, James Bottomley wrote:
   
   Have you checked this with the patches in scsi-misc?  There's a series
   of patches in there that alters the way sdev handling is done.
  
  I would have liked to, but the tree referenced in MAINTAINERS does not
  appear to exist:
  
  git clone 
  git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
  Cloning into 'scsi-misc-2.6'...
  fatal: The remote end hung up unexpectedly
 
 git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git
 
 use the misc branch

joern@Sligo:/usr/src/kernel$ git clone --reference git/ 
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git
Cloning into 'scsi'...
remote: Counting objects: 869, done.
remote: Compressing objects: 100% (420/420), done.
remote: Total 668 (delta 562), reused 274 (delta 248)
Receiving objects: 100% (668/668), 112.59 KiB, done.
Resolving deltas: 100% (562/562), completed with 110 local objects.
Checking out files: 100% (39127/39127), done.
joern@Sligo:/usr/src/kernel$ cd scsi/
joern@Sligo:/usr/src/kernel/scsi$ git branch
* master

Normally I never use branches, so there is a chance that I'm just
clueless.  But to my untrained eye, this looks as if there is no misc
branch.

Jörn

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kind of thief that is conceivable, a thief of spiritual things, a thief of
ideas! It is insufferable, intolerable!
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Re: [git patches] libata updates

2012-07-25 Thread Jeff Garzik
On Wed, Jul 25, 2012 at 04:35:51PM -0400, Jeff Garzik wrote:
 Please pull 641589bff714f39b33ef1d7f02eaa009f2993b64 from
 git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git 
 tags/upstream
 

Oh, I forgot to point out the merge commit, making my HEAD more recent
than might be expected.  There was a merge conflict and an API change
that needed to be dealt with, in order for your pull to be correct.

Jeff



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Re: virtio(-scsi) vs. chained sg_lists (was Re: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list)

2012-07-25 Thread Boaz Harrosh
On 07/25/2012 11:06 PM, Paolo Bonzini wrote:

 Il 25/07/2012 21:16, Boaz Harrosh ha scritto:
 The picture confused me. It looked like the first element is the 
 virtio_scsi_cmd_req
 not an sgilist-element that points to the struct's buffer.

 In that case then yes your plan of making a two-elements fragment that 
 points to the
 original scsi-sglist is perfect. All you have to do is that, and all you 
 have to do
 at virtio is use the sg_for_each macro and you are done.

 You don't need any sglist allocation or reshaping. And you can easily support
 chaining. Looks like order of magnitude more simple then what you do now
 
 It is.
 
 So what is the problem?
 
 That not all architectures have ARCH_HAS_SG_CHAIN (though all those I
 care about do).  So I need to go through all architectures and make sure
 they use for_each_sg, or at least to change ARCH_HAS_SG_CHAIN to a
 Kconfig define so that dependencies can be expressed properly.
 


What is actually preventing ARCH_HAS_SG_CHAIN from all these ARCHES?
is that the DMA drivers not using for_each_sg(). Sounds like easy
to fix.

But yes a deep change would convert ARCH_HAS_SG_CHAIN to a Kconfig.

If you want to be lazy, like me, You might just put a BUILD_BUG_ON
in code, requesting the user to disable the driver for this ARCH.

I bet there is more things to do at ARCH to enable virtualization
then just support ARCH_HAS_SG_CHAIN. Be it just another requirement.

If you Document it and make sure current ARCHs are fine, it should
not ever trigger.

 And BTW you won't need that new __sg_set_page API anymore.
 
 Kind of.
 
sg_init_table(sg, 2);
sg_set_buf(sg[0], req, sizeof(req));
sg_chain(sg[1], scsi_out(sc));
 
 is still a little bit worse than
 
__sg_set_buf(sg[0], req, sizeof(req));
__sg_chain(sg[1], scsi_out(sc));
 


I believe they are the same, specially for the
on the stack 2 elements array. Actually I think
In both cases you need to at least call sg_init_table()
once after allocation, No?

Your old code with big array copy and re-shaping was
a better example of the need for your new API. Which I agree.

But please for my sake do not call it __sg_chain. Call it
something like sg_chain_not_end(). I hate those __ which
for god sack means what? 
(A good name is when I don't have to read the code, an __
 means fuck you go read the code)

 Paolo


Thanks
Boaz
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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Nicholas A. Bellinger
On Wed, 2012-07-25 at 16:10 +0300, Avi Kivity wrote:
 On 07/24/2012 11:45 PM, Nicholas A. Bellinger wrote:
 
   diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
   index e942df9..3d5378f 100644
   --- a/drivers/vhost/tcm_vhost.h
   +++ b/drivers/vhost/tcm_vhost.h
   @@ -80,7 +80,17 @@ struct tcm_vhost_tport {

#include linux/vhost.h

   +/*
   + * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
   + *
   + * ABI Rev 0: All pre 2012 revisions used by prototype out-of-tree code
   + * ABI Rev 1: 2012 version for v3.6 kernel merge candiate
   + */
 
 
 If it's out of tree, why consider it at all?  Put a stable ABI in tree
 and extend it in compatible ways.
 
 

This comment was supposed to convey that ABI=0 vhost-scsi userspace code
is not supported with tcm_vhost mainline code.

But obviously that was not clear enough here.  Updating the comment to
reflect to make this clear.

So the main question here was if it's fine to start with ABI=1, and
require = ABI=1 for all vhost-scsi userspace code to function with
tcm_vhost.

The idea was to avoid confusion for the ABI=0 vhost-scsi code that's
been floating around for the last 2 years.

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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Nicholas A. Bellinger
On Wed, 2012-07-25 at 12:55 +0100, Stefan Hajnoczi wrote:
 On Tue, Jul 24, 2012 at 01:45:24PM -0700, Nicholas A. Bellinger wrote:
  On Mon, 2012-07-23 at 18:56 -0700, Greg Kroah-Hartman wrote:
   On Tue, Jul 24, 2012 at 01:26:20AM +, Nicholas A. Bellinger wrote:
From: Nicholas Bellinger n...@linux-iscsi.org

SNIP

  
diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
index e942df9..3d5378f 100644
--- a/drivers/vhost/tcm_vhost.h
+++ b/drivers/vhost/tcm_vhost.h
@@ -80,7 +80,17 @@ struct tcm_vhost_tport {
 
 #include linux/vhost.h
 
+/*
+ * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
+ *
+ * ABI Rev 0: All pre 2012 revisions used by prototype out-of-tree code
+ * ABI Rev 1: 2012 version for v3.6 kernel merge candiate
+ */
+
+#define VHOST_SCSI_ABI_VERSION 1
+
 struct vhost_scsi_target {
+   int abi_version;
unsigned char vhost_wwpn[TRANSPORT_IQN_LEN];
unsigned short vhost_tpgt;
 };
@@ -88,3 +98,4 @@ struct vhost_scsi_target {
 /* VHOST_SCSI specific defines */
 #define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct 
vhost_scsi_target)
 #define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct 
vhost_scsi_target)
+#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, struct 
vhost_scsi_target)
   
   No, you just broke the ABI for version 0 here, that's not how you do
   this at all.
   
  
  The intention of this patch is use ABI=1 as a starting point for
  tcm_vhost moving forward, with no back-wards compat for the ABI=0
  prototype userspace code because:
  
  - It's based on a slightly older version of QEMU (updating the QEMU series 
  now)
  - It does not have an GET_ABI_VERSION ioctl cmd (that starts with ABI=1)
  - It has a small user-base of target + virtio-scsi developers
  
  So I did consider just starting from ABI=0, but figured this would help
  reduce the confusion for QEMU userspace wrt to the vhost-scsi code
  that's been floating around out-of-tree for the last 2 years.
 
 There is no real user base beyond the handful of people who have hacked
 on this.  Adding the GET_ABI_VERSION ioctl() at this stage is fine,
 especially considering that the userspace code that talks to tcm_vhost
 isn't in mainline in userspace yet either.


Do you have a preference for a VHOST_SCSI_ABI_VERSION starting point
here..?

I thought that v1 would be helpful to avoid confusion with the older
userspace code, but don't really have a strong opinion either way..

Let me know what you'd prefer here, and I'll make the changes to
tcm_vhost + vhost-scsi patch series accordingly.

Thanks!

--nab

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Re: [git patches] libata updates

2012-07-25 Thread Jeff Garzik

On 07/25/2012 04:35 PM, Jeff Garzik wrote:


Please pull 641589bff714f39b33ef1d7f02eaa009f2993b64 from
git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git 
tags/upstream

(text copied from the upstream-linus tag)
Notable changes:

* Updating libata to directly bind with ACPI / runtime power mgmt.
   This is a pre-req for SATA ZPODD (CD-ROM power management).

   Touches ACPI (exports++) and SCSI in minor ways.  Has been in linux-next
   for weeks.

   The rest of [ZPODD] will probably come via SCSI tree, as it involves
   a lot of updates to the 'sr' driver etc.


BTW Lin and Aaron, note that this did not include these changes:

  sr: check support for device busy class events
  sr: support zero power ODD
  sr: make sure ODD is in resumed state in block ioctl

as in the end I wanted to put the brakes on SCSI-touching patches. 
These should be able to go into James' scsi-misc tree with the other 
SCSI-area ZPODD changes.


For those three 'sr' changes listed above, you may add

Acked-by: Jeff Garzik jgar...@redhat.com

when moving them over.

Jeff



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Re: [git patches] libata updates

2012-07-25 Thread Linus Torvalds
On Wed, Jul 25, 2012 at 1:43 PM, Jeff Garzik j...@garzik.org wrote:
 On Wed, Jul 25, 2012 at 04:35:51PM -0400, Jeff Garzik wrote:
 Please pull 641589bff714f39b33ef1d7f02eaa009f2993b64 from
 git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git 
 tags/upstream


 Oh, I forgot to point out the merge commit, making my HEAD more recent
 than might be expected.  There was a merge conflict and an API change
 that needed to be dealt with, in order for your pull to be correct.

So I'd *much* rather see an explanation of what the conflict is when
you ask me to pull, and let me handle it, rather than you pre-merging
things for me. I *want* to see conflicts between subsystems.
Seriously.

   Linus
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Re: [git patches] libata updates

2012-07-25 Thread Jeff Garzik

On 07/25/2012 06:06 PM, Linus Torvalds wrote:

On Wed, Jul 25, 2012 at 1:43 PM, Jeff Garzik j...@garzik.org wrote:

On Wed, Jul 25, 2012 at 04:35:51PM -0400, Jeff Garzik wrote:

Please pull 641589bff714f39b33ef1d7f02eaa009f2993b64 from
git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git 
tags/upstream



Oh, I forgot to point out the merge commit, making my HEAD more recent
than might be expected.  There was a merge conflict and an API change
that needed to be dealt with, in order for your pull to be correct.


So I'd *much* rather see an explanation of what the conflict is when
you ask me to pull, and let me handle it, rather than you pre-merging
things for me. I *want* to see conflicts between subsystems.
Seriously.


Tried to add some explanation to the merge commit itself, giving plenty 
of detail.


Even so, separately, it still needed that post-merge compile fix.

Jeff



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Re: [git patches] libata updates

2012-07-25 Thread Linus Torvalds
On Wed, Jul 25, 2012 at 3:26 PM, Jeff Garzik jgar...@pobox.com wrote:

 Even so, separately, it still needed that post-merge compile fix.

And that's yet another example of how *NOT* to do things.

If the merge has errors like that, then they should be fixed up in the merge.

Please. Don't do this. Let me merge stuff, and you explain in the pull
request why it gets merge problems. Not this mess.

That merge itself was *trivial*. I do those kinds of fixups in my
sleep and you don't even need to explain those. The non-trivial part
you did as a separate commit. But neither of those should have been
I'll pre-merge for Linus so that he doesn't see these problems.

  Linus
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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Stefan Hajnoczi
On Wed, Jul 25, 2012 at 02:14:50PM -0700, Nicholas A. Bellinger wrote:
 On Wed, 2012-07-25 at 12:55 +0100, Stefan Hajnoczi wrote:
  On Tue, Jul 24, 2012 at 01:45:24PM -0700, Nicholas A. Bellinger wrote:
   On Mon, 2012-07-23 at 18:56 -0700, Greg Kroah-Hartman wrote:
On Tue, Jul 24, 2012 at 01:26:20AM +, Nicholas A. Bellinger wrote:
 From: Nicholas Bellinger n...@linux-iscsi.org
 
 SNIP
 
   
 diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
 index e942df9..3d5378f 100644
 --- a/drivers/vhost/tcm_vhost.h
 +++ b/drivers/vhost/tcm_vhost.h
 @@ -80,7 +80,17 @@ struct tcm_vhost_tport {
  
  #include linux/vhost.h
  
 +/*
 + * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
 + *
 + * ABI Rev 0: All pre 2012 revisions used by prototype out-of-tree 
 code
 + * ABI Rev 1: 2012 version for v3.6 kernel merge candiate
 + */
 +
 +#define VHOST_SCSI_ABI_VERSION   1
 +
  struct vhost_scsi_target {
 + int abi_version;
   unsigned char vhost_wwpn[TRANSPORT_IQN_LEN];
   unsigned short vhost_tpgt;
  };
 @@ -88,3 +98,4 @@ struct vhost_scsi_target {
  /* VHOST_SCSI specific defines */
  #define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct 
 vhost_scsi_target)
  #define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct 
 vhost_scsi_target)
 +#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, struct 
 vhost_scsi_target)

No, you just broke the ABI for version 0 here, that's not how you do
this at all.

   
   The intention of this patch is use ABI=1 as a starting point for
   tcm_vhost moving forward, with no back-wards compat for the ABI=0
   prototype userspace code because:
   
   - It's based on a slightly older version of QEMU (updating the QEMU 
   series now)
   - It does not have an GET_ABI_VERSION ioctl cmd (that starts with ABI=1)
   - It has a small user-base of target + virtio-scsi developers
   
   So I did consider just starting from ABI=0, but figured this would help
   reduce the confusion for QEMU userspace wrt to the vhost-scsi code
   that's been floating around out-of-tree for the last 2 years.
  
  There is no real user base beyond the handful of people who have hacked
  on this.  Adding the GET_ABI_VERSION ioctl() at this stage is fine,
  especially considering that the userspace code that talks to tcm_vhost
  isn't in mainline in userspace yet either.
 
 
 Do you have a preference for a VHOST_SCSI_ABI_VERSION starting point
 here..?
 
 I thought that v1 would be helpful to avoid confusion with the older
 userspace code, but don't really have a strong opinion either way..
 
 Let me know what you'd prefer here, and I'll make the changes to
 tcm_vhost + vhost-scsi patch series accordingly.

I don't think 0 for out-of-tree is needed.  I'd start at 0 but either
way is okay.

The main thing I would like to confirm is that this only versions the
tcm_vhost ioctls?  In that case a single version number works.

Stefan

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Re: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread tomm
Tejun Heo tj at kernel.org writes:

 
 Hello,
 
 On Sat, Jul 21, 2012 at 02:15:56PM +0200, Matthias Prager wrote:
  Now I'm not sure this isn't taping over another bug. Which leads me to
  my question: What is the correct behavior?
  
  #1 Issuing a separate spin-up command (START UNIT?) prior to sending i/o
  by setting allow_restart=1 for sata disks on sas controllers
  
  or
  
  #2 Teaching the sas drivers they do not need spin-up commands and can
  simply start issuing i/o to sata disks
 
 I haven't consulted SAT but it seems like a bug in SAS driver or
 firmware.  If it's a driver bug, we better fix it there.  If a
 firmware bug, working around those is one of major roles of drivers,
 so I think setting allow_restart is fine.
 
 Thanks.
 
If this is a driver or firmware bug, then why would commit
85ef06d1d252f6a2e73b678591ab71caad4667bb 
cause this to happen?  What is the interaction between this issue
and this commit which just flushes events?

Also this issue does not happen with mvsas, only with mpt2sas.




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Re: [git patches] libata updates

2012-07-25 Thread Jeff Garzik

On 07/25/2012 06:31 PM, Linus Torvalds wrote:

On Wed, Jul 25, 2012 at 3:26 PM, Jeff Garzik jgar...@pobox.com wrote:


Even so, separately, it still needed that post-merge compile fix.


And that's yet another example of how *NOT* to do things.

If the merge has errors like that, then they should be fixed up in the merge.

Please. Don't do this. Let me merge stuff, and you explain in the pull
request why it gets merge problems. Not this mess.

That merge itself was *trivial*. I do those kinds of fixups in my
sleep and you don't even need to explain those. The non-trivial part
you did as a separate commit. But neither of those should have been
I'll pre-merge for Linus so that he doesn't see these problems.


What is the right course in when a post-merge change is needed?

Jeff





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Re: 'Device not ready' issue on mpt2sas since 3.1.10

2012-07-25 Thread Matthias Prager
Hello James,

Am 25.07.2012 21:55, schrieb James Bottomley:
 It looks like a hack like this might be needed.

 James


SNIP

I don't yet understand all the code but I'm following your discussion
with Tejun: I've set up a minimal vm running gentoo with a mpt2sas
driven controller in passthrough mode. I've applied your proposed patch
against the vanilla 3.5.0 kernel (which includes Tejun's commit), and
I'm happy to report the problem does seem to get fixed by it.
Well at least sending the sata drive in standby using 'hdparm -y' now
works (according to 'hdparm -C') without these nasty i/o errors on later
i/o. That is to say the drive wakes up again (e.g. from a 'fdisk -l
/dev/sda' command) and returns data.

--
Matthias
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Re: [git patches] libata updates

2012-07-25 Thread Jeff Garzik

On 07/25/2012 07:30 PM, Linus Torvalds wrote:

On Wed, Jul 25, 2012 at 3:58 PM, Jeff Garzik jgar...@pobox.com wrote:


What is the right course in when a post-merge change is needed?


Just describe the issue and the required change. Than I can just do it
as part of the merge, and now the whole series is bisectable,
including the merge itself.

Here's a (fairly bad) example:

   http://www.spinics.net/lists/netdev/msg192349.html

and the reason I call that a bad example is not because that's a bad
pull request, but simply that those are all real data conflicts, not
the more subtle kind of it merges fine, but because new code
introduced uses an interface that changed, you need to do xyz.


Thanks, so noted.  I guess if the merge gets more complex than something 
easily described in an email, that implies that maintainers should do 
more cross-coordination and maybe a merge tree.


What's the best way for libata to move forward, now that this hideous 
merge has been pushed out to the Well Known libata branches?  The 
pre-jgarzik-merge commit you would have pulled is 
dc7f71f486f4f5fa96f6dcf86833da020cde8a11 had my pull request been proper.


I can lop off the top 3 commits and force-update the libata-dev.git 
branches, then send a new pull request -- but you have grumbled at that 
sort of behavior in maintainer trees before too...


Jeff


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Re: [PATCH] tcm_vhost: Expose ABI version via VHOST_SCSI_GET_ABI_VERSION

2012-07-25 Thread Nicholas A. Bellinger
On Wed, 2012-07-25 at 23:35 +0100, Stefan Hajnoczi wrote:
 On Wed, Jul 25, 2012 at 02:14:50PM -0700, Nicholas A. Bellinger wrote:
  On Wed, 2012-07-25 at 12:55 +0100, Stefan Hajnoczi wrote:
   On Tue, Jul 24, 2012 at 01:45:24PM -0700, Nicholas A. Bellinger wrote:
On Mon, 2012-07-23 at 18:56 -0700, Greg Kroah-Hartman wrote:
 On Tue, Jul 24, 2012 at 01:26:20AM +, Nicholas A. Bellinger wrote:
  From: Nicholas Bellinger n...@linux-iscsi.org

SNIP

The intention of this patch is use ABI=1 as a starting point for
tcm_vhost moving forward, with no back-wards compat for the ABI=0
prototype userspace code because:

- It's based on a slightly older version of QEMU (updating the QEMU 
series now)
- It does not have an GET_ABI_VERSION ioctl cmd (that starts with ABI=1)
- It has a small user-base of target + virtio-scsi developers

So I did consider just starting from ABI=0, but figured this would help
reduce the confusion for QEMU userspace wrt to the vhost-scsi code
that's been floating around out-of-tree for the last 2 years.
   
   There is no real user base beyond the handful of people who have hacked
   on this.  Adding the GET_ABI_VERSION ioctl() at this stage is fine,
   especially considering that the userspace code that talks to tcm_vhost
   isn't in mainline in userspace yet either.
  
  
  Do you have a preference for a VHOST_SCSI_ABI_VERSION starting point
  here..?
  
  I thought that v1 would be helpful to avoid confusion with the older
  userspace code, but don't really have a strong opinion either way..
  
  Let me know what you'd prefer here, and I'll make the changes to
  tcm_vhost + vhost-scsi patch series accordingly.
 
 I don't think 0 for out-of-tree is needed.  I'd start at 0 but either
 way is okay.
 

nod

In that case, respinning a -v5 for tcm_vhost to start from ABI=0 and
will post an updated patch shortly.

 The main thing I would like to confirm is that this only versions the
 tcm_vhost ioctls?  In that case a single version number works.
 

Correct, the GET_ABI_VERSION call is only intended to identify the
changing of tcm_vhost ioctls.

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Re: [git patches] libata updates

2012-07-25 Thread Aaron Lu

On 07/26/2012 05:38 AM, Jeff Garzik wrote:

On 07/25/2012 04:35 PM, Jeff Garzik wrote:

* Updating libata to directly bind with ACPI / runtime power mgmt.
This is a pre-req for SATA ZPODD (CD-ROM power management).

Touches ACPI (exports++) and SCSI in minor ways. Has been in linux-next
for weeks.

The rest of [ZPODD] will probably come via SCSI tree, as it involves
a lot of updates to the 'sr' driver etc.


BTW Lin and Aaron, note that this did not include these changes:

sr: check support for device busy class events
sr: support zero power ODD
sr: make sure ODD is in resumed state in block ioctl

as in the end I wanted to put the brakes on SCSI-touching patches. These
should be able to go into James' scsi-misc tree with the other SCSI-area
ZPODD changes.

For those three 'sr' changes listed above, you may add

Acked-by: Jeff Garzik jgar...@redhat.com

when moving them over.


Thanks Jeff.

Hi James,
I'll prepare these dropped patches plus some other fixes for ZPODD which
I've sent v2 recently and merge them into v3 for you to review.

Thanks,
Aaron

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Re: [git patches] libata updates

2012-07-25 Thread James Bottomley
On Thu, 2012-07-26 at 12:47 +0800, Aaron Lu wrote:
 On 07/26/2012 05:38 AM, Jeff Garzik wrote:
  On 07/25/2012 04:35 PM, Jeff Garzik wrote:
  * Updating libata to directly bind with ACPI / runtime power mgmt.
  This is a pre-req for SATA ZPODD (CD-ROM power management).
 
  Touches ACPI (exports++) and SCSI in minor ways. Has been in linux-next
  for weeks.
 
  The rest of [ZPODD] will probably come via SCSI tree, as it involves
  a lot of updates to the 'sr' driver etc.
 
  BTW Lin and Aaron, note that this did not include these changes:
 
  sr: check support for device busy class events
  sr: support zero power ODD
  sr: make sure ODD is in resumed state in block ioctl
 
  as in the end I wanted to put the brakes on SCSI-touching patches. These
  should be able to go into James' scsi-misc tree with the other SCSI-area
  ZPODD changes.
 
  For those three 'sr' changes listed above, you may add
 
  Acked-by: Jeff Garzik jgar...@redhat.com
 
  when moving them over.
 
 Thanks Jeff.
 
 Hi James,
 I'll prepare these dropped patches plus some other fixes for ZPODD which
 I've sent v2 recently and merge them into v3 for you to review.

They weren't exactly dropped ... I've been waiting for you to address
Alan Stern's comments, since he's our resident expert on suspend/resume.

James


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RE: [GIT PATCH 0/4] isci update for 3.6

2012-07-25 Thread James Bottomley
On Wed, 2012-07-25 at 23:08 +, Skirvin, Jeffrey D wrote:
 James, is there any update available about the pull of the driver changes that
 Dan mentioned?  Please let me know if there is anything we need to do to 
 assist.

Oh, oops.  When I had to rebase the branches to accommodate Linus' fix
for the async problem, this got lost.  I'll readd it.

James


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Re: [git patches] libata updates

2012-07-25 Thread Aaron Lu

On 07/26/2012 01:05 PM, James Bottomley wrote:

On Thu, 2012-07-26 at 12:47 +0800, Aaron Lu wrote:

On 07/26/2012 05:38 AM, Jeff Garzik wrote:

On 07/25/2012 04:35 PM, Jeff Garzik wrote:

* Updating libata to directly bind with ACPI / runtime power mgmt.
This is a pre-req for SATA ZPODD (CD-ROM power management).

Touches ACPI (exports++) and SCSI in minor ways. Has been in linux-next
for weeks.

The rest of [ZPODD] will probably come via SCSI tree, as it involves
a lot of updates to the 'sr' driver etc.


BTW Lin and Aaron, note that this did not include these changes:

sr: check support for device busy class events
sr: support zero power ODD
sr: make sure ODD is in resumed state in block ioctl

as in the end I wanted to put the brakes on SCSI-touching patches. These
should be able to go into James' scsi-misc tree with the other SCSI-area
ZPODD changes.

For those three 'sr' changes listed above, you may add

Acked-by: Jeff Garzikjgar...@redhat.com

when moving them over.


Thanks Jeff.

Hi James,
I'll prepare these dropped patches plus some other fixes for ZPODD which
I've sent v2 recently and merge them into v3 for you to review.


They weren't exactly dropped ... I've been waiting for you to address
Alan Stern's comments, since he's our resident expert on suspend/resume.


Oh, I forgot to mention, that I agree with Alan's comments and have
addressed them in my v2 patches here:
http://marc.info/?l=linux-scsim=134312317325650w=2

The 2 patches Alan has comments are:
http://marc.info/?l=linux-scsim=134312311025619w=2
http://marc.info/?l=linux-scsim=134312308225610w=2

Hi Alan,
Are the v2 patches look OK to you?

And James,
Do you want me to rebase these patches on top of scsi-misc tree?

Thanks,
Aaron

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