Re: [PATCH 37/45] drivers: use req op accessor

2016-08-04 Thread Shaun Tancheff 
On Thu, Aug 4, 2016 at 10:46 AM, Christoph Hellwig  wrote:
> On Wed, Aug 03, 2016 at 07:30:29PM -0500, Shaun Tancheff wrote:
>> I think the translation in loop.c is suspicious here:
>>
>> "if use DIO && not (a flush_flag or discard_flag)"
>> should translate to:
>> "if use DIO && not ((a flush_flag) || op == discard)"
>>
>> But in the patch I read:
>> "if use DIO && ((not a flush_flag) || op == discard)
>>
>> Which would have DIO && discards follow the AIO path?
>
> Indeed.  Sorry for missing out on your patch, I just sent a fix
> in reply to Dave's other report earlier which is pretty similar to
> yours.

No worries. I prefer your switch to a an if conditional here.

-- 
Shaun Tancheff

Re: [PATCH 37/45] drivers: use req op accessor

2016-08-04 Thread Christoph Hellwig 
On Wed, Aug 03, 2016 at 07:30:29PM -0500, Shaun Tancheff wrote:
> I think the translation in loop.c is suspicious here:
> 
> "if use DIO && not (a flush_flag or discard_flag)"
> should translate to:
> "if use DIO && not ((a flush_flag) || op == discard)"
> 
> But in the patch I read:
> "if use DIO && ((not a flush_flag) || op == discard)
> 
> Which would have DIO && discards follow the AIO path?

Indeed.  Sorry for missing out on your patch, I just sent a fix
in reply to Dave's other report earlier which is pretty similar to
yours.

Re: [PATCH 37/45] drivers: use req op accessor

2016-08-03 Thread Mike Christie 
On 08/03/2016 07:30 PM, Shaun Tancheff wrote:
> On Wed, Aug 3, 2016 at 6:47 PM, Mike Christie  wrote:
>> On 08/03/2016 05:33 PM, Ross Zwisler wrote:
>>> On Sun, Jun 5, 2016 at 1:32 PM,   wrote:
 From: Mike Christie 

 The req operation REQ_OP is separated from the rq_flag_bits
 definition. This converts the block layer drivers to
 use req_op to get the op from the request struct.

 Signed-off-by: Mike Christie 
 ---
  drivers/block/loop.c  |  6 +++---
  drivers/block/mtip32xx/mtip32xx.c |  2 +-
  drivers/block/nbd.c   |  2 +-
  drivers/block/rbd.c   |  4 ++--
  drivers/block/xen-blkfront.c  |  8 +---
  drivers/ide/ide-floppy.c  |  2 +-
  drivers/md/dm.c   |  2 +-
  drivers/mmc/card/block.c  |  7 +++
  drivers/mmc/card/queue.c  |  6 ++
>>>
>>> Dave Chinner reported a deadlock with XFS + DAX, which I reproduced
>>> and bisected to this commit:
>>>
>>> commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34
>>> Author: Mike Christie 
>>> Date:   Sun Jun 5 14:32:17 2016 -0500
>>> drivers: use req op accessor
>>>
>>> Here are the steps to reproduce the deadlock with a BRD ramdisk:
>>>
>>> mkfs.xfs -f /dev/ram0
>>> mount -o dax /dev/ram0 /mnt/scratch
>>
>> When using ramdisks, we need the attached patch like in your other bug
>> report. I think it will fix some hangs people are seeing.
>>
>> I do not think that it should cause the failure to run issue you saw
>> when doing generic/008 and ext2.
>>
> 
> I think the translation in loop.c is suspicious here:
> 
> "if use DIO && not (a flush_flag or discard_flag)"
> should translate to:
> "if use DIO && not ((a flush_flag) || op == discard)"
> 
> But in the patch I read:
> "if use DIO && ((not a flush_flag) || op == discard)
> 
> Which would have DIO && discards follow the AIO path?
> 
> So I would humbly suggest something like the following
> (on top of commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34):
> [Please excuse the messed up patch format ... gmail eats tabs]
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index b9b737c..0754d83 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1659,8 +1659,9 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
> if (lo->lo_state != Lo_bound)
> return -EIO;
> 
> -   if (lo->use_dio && (!(cmd->rq->cmd_flags & REQ_FLUSH) ||
> -   req_op(cmd->rq) == REQ_OP_DISCARD))
> +   if (lo->use_dio && !(
> +   (cmd->rq->cmd_flags & REQ_FLUSH) ||
> +req_op(cmd->rq) == REQ_OP_DISCARD))
> cmd->use_aio = true;
> else
> cmd->use_aio = false;
> 

You are right. The translation was bad and your code above is correct.

I think we need my patch in the other mail though too, because for the
rw_page user case if WB_SYNC_ALL is set, then the IO gets sent down as a
read instead of a write.

Re: [PATCH 37/45] drivers: use req op accessor

2016-08-03 Thread Shaun Tancheff 
On Wed, Aug 3, 2016 at 6:47 PM, Mike Christie  wrote:
> On 08/03/2016 05:33 PM, Ross Zwisler wrote:
>> On Sun, Jun 5, 2016 at 1:32 PM,   wrote:
>>> From: Mike Christie 
>>>
>>> The req operation REQ_OP is separated from the rq_flag_bits
>>> definition. This converts the block layer drivers to
>>> use req_op to get the op from the request struct.
>>>
>>> Signed-off-by: Mike Christie 
>>> ---
>>>  drivers/block/loop.c  |  6 +++---
>>>  drivers/block/mtip32xx/mtip32xx.c |  2 +-
>>>  drivers/block/nbd.c   |  2 +-
>>>  drivers/block/rbd.c   |  4 ++--
>>>  drivers/block/xen-blkfront.c  |  8 +---
>>>  drivers/ide/ide-floppy.c  |  2 +-
>>>  drivers/md/dm.c   |  2 +-
>>>  drivers/mmc/card/block.c  |  7 +++
>>>  drivers/mmc/card/queue.c  |  6 ++
>>
>> Dave Chinner reported a deadlock with XFS + DAX, which I reproduced
>> and bisected to this commit:
>>
>> commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34
>> Author: Mike Christie 
>> Date:   Sun Jun 5 14:32:17 2016 -0500
>> drivers: use req op accessor
>>
>> Here are the steps to reproduce the deadlock with a BRD ramdisk:
>>
>> mkfs.xfs -f /dev/ram0
>> mount -o dax /dev/ram0 /mnt/scratch
>
> When using ramdisks, we need the attached patch like in your other bug
> report. I think it will fix some hangs people are seeing.
>
> I do not think that it should cause the failure to run issue you saw
> when doing generic/008 and ext2.
>

I think the translation in loop.c is suspicious here:

"if use DIO && not (a flush_flag or discard_flag)"
should translate to:
"if use DIO && not ((a flush_flag) || op == discard)"

But in the patch I read:
"if use DIO && ((not a flush_flag) || op == discard)

Which would have DIO && discards follow the AIO path?

So I would humbly suggest something like the following
(on top of commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34):
[Please excuse the messed up patch format ... gmail eats tabs]

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b9b737c..0754d83 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1659,8 +1659,9 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
if (lo->lo_state != Lo_bound)
return -EIO;

-   if (lo->use_dio && (!(cmd->rq->cmd_flags & REQ_FLUSH) ||
-   req_op(cmd->rq) == REQ_OP_DISCARD))
+   if (lo->use_dio && !(
+   (cmd->rq->cmd_flags & REQ_FLUSH) ||
+req_op(cmd->rq) == REQ_OP_DISCARD))
cmd->use_aio = true;
else
cmd->use_aio = false;

-- 
Shaun Tancheff

Re: [PATCH 37/45] drivers: use req op accessor

2016-08-03 Thread Mike Christie 
On 08/03/2016 05:33 PM, Ross Zwisler wrote:
> On Sun, Jun 5, 2016 at 1:32 PM,   wrote:
>> From: Mike Christie 
>>
>> The req operation REQ_OP is separated from the rq_flag_bits
>> definition. This converts the block layer drivers to
>> use req_op to get the op from the request struct.
>>
>> Signed-off-by: Mike Christie 
>> ---
>>  drivers/block/loop.c  |  6 +++---
>>  drivers/block/mtip32xx/mtip32xx.c |  2 +-
>>  drivers/block/nbd.c   |  2 +-
>>  drivers/block/rbd.c   |  4 ++--
>>  drivers/block/xen-blkfront.c  |  8 +---
>>  drivers/ide/ide-floppy.c  |  2 +-
>>  drivers/md/dm.c   |  2 +-
>>  drivers/mmc/card/block.c  |  7 +++
>>  drivers/mmc/card/queue.c  |  6 ++
> 
> Dave Chinner reported a deadlock with XFS + DAX, which I reproduced
> and bisected to this commit:
> 
> commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34
> Author: Mike Christie 
> Date:   Sun Jun 5 14:32:17 2016 -0500
> drivers: use req op accessor
> 
> Here are the steps to reproduce the deadlock with a BRD ramdisk:
> 
> mkfs.xfs -f /dev/ram0
> mount -o dax /dev/ram0 /mnt/scratch

When using ramdisks, we need the attached patch like in your other bug
report. I think it will fix some hangs people are seeing.

I do not think that it should cause the failure to run issue you saw
when doing generic/008 and ext2.

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 3022dad..9fbbeba 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -300,20 +300,20 @@ static void copy_from_brd(void *dst, struct brd_device *brd,
  * Process a single bvec of a bio.
  */
 static int brd_do_bvec(struct brd_device *brd, struct page *page,
-			unsigned int len, unsigned int off, int rw,
+			unsigned int len, unsigned int off, int op,
 			sector_t sector)
 {
 	void *mem;
 	int err = 0;
 
-	if (rw != READ) {
+	if (op_is_write(op)) {
 		err = copy_to_brd_setup(brd, sector, len);
 		if (err)
 			goto out;
 	}
 
 	mem = kmap_atomic(page);
-	if (rw == READ) {
+	if (!op_is_write(op)) {
 		copy_from_brd(mem + off, brd, sector, len);
 		flush_dcache_page(page);
 	} else {
@@ -330,7 +330,6 @@ static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio)
 {
 	struct block_device *bdev = bio->bi_bdev;
 	struct brd_device *brd = bdev->bd_disk->private_data;
-	int rw;
 	struct bio_vec bvec;
 	sector_t sector;
 	struct bvec_iter iter;
@@ -347,14 +346,12 @@ static blk_qc_t brd_make_request(struct request_queue *q, struct bio *bio)
 		goto out;
 	}
 
-	rw = bio_data_dir(bio);
-
 	bio_for_each_segment(bvec, bio, iter) {
 		unsigned int len = bvec.bv_len;
 		int err;
 
 		err = brd_do_bvec(brd, bvec.bv_page, len,
-	bvec.bv_offset, rw, sector);
+	bvec.bv_offset, bio_op(bio), sector);
 		if (err)
 			goto io_error;
 		sector += len >> SECTOR_SHIFT;
@@ -369,11 +366,11 @@ io_error:
 }
 
 static int brd_rw_page(struct block_device *bdev, sector_t sector,
-		   struct page *page, int rw)
+		   struct page *page, int op, int op_flags)
 {
 	struct brd_device *brd = bdev->bd_disk->private_data;
-	int err = brd_do_bvec(brd, page, PAGE_SIZE, 0, rw, sector);
-	page_endio(page, rw & WRITE, err);
+	int err = brd_do_bvec(brd, page, PAGE_SIZE, 0, op, sector);
+	page_endio(page, op, err);
 	return err;
 }
 
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7454cf1..f0e126c 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -843,15 +843,15 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 }
 
 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
-			int offset, int rw)
+			int offset, int op)
 {
 	unsigned long start_time = jiffies;
 	int ret;
 
-	generic_start_io_acct(rw, bvec->bv_len >> SECTOR_SHIFT,
+	generic_start_io_acct(op, bvec->bv_len >> SECTOR_SHIFT,
 			&zram->disk->part0);
 
-	if (rw == READ) {
+	if (!op_is_write(op)) {
 		atomic64_inc(&zram->stats.num_reads);
 		ret = zram_bvec_read(zram, bvec, index, offset);
 	} else {
@@ -859,10 +859,10 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 		ret = zram_bvec_write(zram, bvec, index, offset);
 	}
 
-	generic_end_io_acct(rw, &zram->disk->part0, start_time);
+	generic_end_io_acct(op, &zram->disk->part0, start_time);
 
 	if (unlikely(ret)) {
-		if (rw == READ)
+		if (!op_is_write(op))
 			atomic64_inc(&zram->stats.failed_reads);
 		else
 			atomic64_inc(&zram->stats.failed_writes);
@@ -873,7 +873,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 
 static void __zram_make_request(struct zram *zram, struct bio *bio)
 {
-	int offset, rw;
+	int offset;
 	u32 index;
 	struct bio_vec bvec;
 	struct bvec_iter iter;
@@ -888,7 +888,6 @@ static void __zram_make_request(struct zram *zram, struct bio *bio)
 		return;
 	}
 
-	rw = bio_data_dir(bio);
 	bio_for_each_segment(bvec, bio, iter) {
 		int max_transfer_size = PAGE_SIZE - offset;
 
@@ -903,15 +902,18 @@ static v

Re: [PATCH 37/45] drivers: use req op accessor

2016-08-03 Thread Ross Zwisler 
On Sun, Jun 5, 2016 at 1:32 PM,   wrote:
> From: Mike Christie 
>
> The req operation REQ_OP is separated from the rq_flag_bits
> definition. This converts the block layer drivers to
> use req_op to get the op from the request struct.
>
> Signed-off-by: Mike Christie 
> ---
>  drivers/block/loop.c  |  6 +++---
>  drivers/block/mtip32xx/mtip32xx.c |  2 +-
>  drivers/block/nbd.c   |  2 +-
>  drivers/block/rbd.c   |  4 ++--
>  drivers/block/xen-blkfront.c  |  8 +---
>  drivers/ide/ide-floppy.c  |  2 +-
>  drivers/md/dm.c   |  2 +-
>  drivers/mmc/card/block.c  |  7 +++
>  drivers/mmc/card/queue.c  |  6 ++

Dave Chinner reported a deadlock with XFS + DAX, which I reproduced
and bisected to this commit:

commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34
Author: Mike Christie 
Date:   Sun Jun 5 14:32:17 2016 -0500
drivers: use req op accessor

Here are the steps to reproduce the deadlock with a BRD ramdisk:

mkfs.xfs -f /dev/ram0
mount -o dax /dev/ram0 /mnt/scratch
xfs_io -f -c "truncate 1g" /mnt/scratch/test.img
losetup -f --show /mnt/scratch/test.img
mkfs.xfs -f /dev/loop0

At this point the mkfs.xfs deadlocks.  Here is the stack trace
gathered via "echo w > /proc/sysrq-trigger" and passed through
kasan_symbolize.py:

brd: module loaded
XFS (ram0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk
XFS (ram0): Mounting V5 Filesystem
XFS (ram0): Ending clean mount
sysrq: SysRq : Show Blocked State
  taskPC stack   pid father
mkfs.xfsD 88060ae47b38 0  1482   1287 0x
 88060ae47b38 79e8 880610fd8d98 880036011a40
 8800aa6dcec0 88060ae48000 880610fd8d80 7fff
 8800aa6dcec0 024000c0 88060ae47b50 81aca775
Call Trace:
 [] schedule+0x35/0x80 kernel/sched/core.c:3360
 [] schedule_timeout+0x271/0x460 kernel/time/timer.c:1493
 [] io_schedule_timeout+0xa4/0x110 kernel/sched/core.c:4969
 [< inline >] do_wait_for_common kernel/sched/completion.c:75
 [< inline >] __wait_for_common kernel/sched/completion.c:93
 [< inline >] wait_for_common_io kernel/sched/completion.c:107
 [] wait_for_completion_io+0xdf/0x120
kernel/sched/completion.c:155
 [] submit_bio_wait+0x66/0x90 block/bio.c:870
 [] blkdev_issue_discard+0x86/0xc0 block/blk-lib.c:115
 [] blk_ioctl_discard+0xa3/0xd0 block/ioctl.c:221
 [] blkdev_ioctl+0x60a/0x9e0 block/ioctl.c:510
 [] block_ioctl+0x43/0x50 fs/block_dev.c:1714
 [< inline >] vfs_ioctl fs/ioctl.c:43
 [] do_vfs_ioctl+0xa2/0x6a0 fs/ioctl.c:674
 [< inline >] SYSC_ioctl fs/ioctl.c:689
 [] SyS_ioctl+0x79/0x90 fs/ioctl.c:680
 [] entry_SYSCALL_64_fastpath+0x1f/0xbd
arch/x86/entry/entry_64.S:207

The line numbers are for the commit above, not for linux/master.  This
occurs 100% as of this commit, and 0% with the previous commit.

This doesn't occur if you don't use DAX, but based on the content of
the commit I'm guessing that difference is due to variations in the
way the two paths use discard.

- Ross

Re: [PATCH 37/45] drivers: use req op accessor

2016-06-05 Thread Hannes Reinecke 
On 06/05/2016 09:32 PM, mchri...@redhat.com wrote:
> From: Mike Christie 
> 
> The req operation REQ_OP is separated from the rq_flag_bits
> definition. This converts the block layer drivers to
> use req_op to get the op from the request struct.
> 
> Signed-off-by: Mike Christie 
> ---
>  drivers/block/loop.c  |  6 +++---
>  drivers/block/mtip32xx/mtip32xx.c |  2 +-
>  drivers/block/nbd.c   |  2 +-
>  drivers/block/rbd.c   |  4 ++--
>  drivers/block/xen-blkfront.c  |  8 +---
>  drivers/ide/ide-floppy.c  |  2 +-
>  drivers/md/dm.c   |  2 +-
>  drivers/mmc/card/block.c  |  7 +++
>  drivers/mmc/card/queue.c  |  6 ++
>  drivers/mmc/card/queue.h  |  5 -
>  drivers/mtd/mtd_blkdevs.c |  2 +-
>  drivers/nvme/host/core.c  |  2 +-
>  drivers/nvme/host/nvme.h  |  4 ++--
>  drivers/scsi/sd.c | 25 -
>  14 files changed, 43 insertions(+), 34 deletions(-)
> 
Reviewed-by: Hannes Reinecke 

Cheers,

Hannes
-- 
Dr. Hannes ReineckeTeamlead Storage & Networking
h...@suse.de   +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

[PATCH 37/45] drivers: use req op accessor

2016-06-05 Thread mchristi 
From: Mike Christie 

The req operation REQ_OP is separated from the rq_flag_bits
definition. This converts the block layer drivers to
use req_op to get the op from the request struct.

Signed-off-by: Mike Christie 
---
 drivers/block/loop.c  |  6 +++---
 drivers/block/mtip32xx/mtip32xx.c |  2 +-
 drivers/block/nbd.c   |  2 +-
 drivers/block/rbd.c   |  4 ++--
 drivers/block/xen-blkfront.c  |  8 +---
 drivers/ide/ide-floppy.c  |  2 +-
 drivers/md/dm.c   |  2 +-
 drivers/mmc/card/block.c  |  7 +++
 drivers/mmc/card/queue.c  |  6 ++
 drivers/mmc/card/queue.h  |  5 -
 drivers/mtd/mtd_blkdevs.c |  2 +-
 drivers/nvme/host/core.c  |  2 +-
 drivers/nvme/host/nvme.h  |  4 ++--
 drivers/scsi/sd.c | 25 -
 14 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index e9f1701..b9b737c 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -544,7 +544,7 @@ static int do_req_filebacked(struct loop_device *lo, struct 
request *rq)
if (op_is_write(req_op(rq))) {
if (rq->cmd_flags & REQ_FLUSH)
ret = lo_req_flush(lo, rq);
-   else if (rq->cmd_flags & REQ_DISCARD)
+   else if (req_op(rq) == REQ_OP_DISCARD)
ret = lo_discard(lo, rq, pos);
else if (lo->transfer)
ret = lo_write_transfer(lo, rq, pos);
@@ -1659,8 +1659,8 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
if (lo->lo_state != Lo_bound)
return -EIO;
 
-   if (lo->use_dio && !(cmd->rq->cmd_flags & (REQ_FLUSH |
-   REQ_DISCARD)))
+   if (lo->use_dio && (!(cmd->rq->cmd_flags & REQ_FLUSH) ||
+   req_op(cmd->rq) == REQ_OP_DISCARD))
cmd->use_aio = true;
else
cmd->use_aio = false;
diff --git a/drivers/block/mtip32xx/mtip32xx.c 
b/drivers/block/mtip32xx/mtip32xx.c
index 6053e46..8e3e708 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3765,7 +3765,7 @@ static int mtip_submit_request(struct blk_mq_hw_ctx 
*hctx, struct request *rq)
return -ENODATA;
}
 
-   if (rq->cmd_flags & REQ_DISCARD) {
+   if (req_op(rq) == REQ_OP_DISCARD) {
int err;
 
err = mtip_send_trim(dd, blk_rq_pos(rq), blk_rq_sectors(rq));
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 31e73a7..6c2c28d 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -282,7 +282,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct 
request *req)
 
if (req->cmd_type == REQ_TYPE_DRV_PRIV)
type = NBD_CMD_DISC;
-   else if (req->cmd_flags & REQ_DISCARD)
+   else if (req_op(req) == REQ_OP_DISCARD)
type = NBD_CMD_TRIM;
else if (req->cmd_flags & REQ_FLUSH)
type = NBD_CMD_FLUSH;
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 81666a5..4506620 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3286,9 +3286,9 @@ static void rbd_queue_workfn(struct work_struct *work)
goto err;
}
 
-   if (rq->cmd_flags & REQ_DISCARD)
+   if (req_op(rq) == REQ_OP_DISCARD)
op_type = OBJ_OP_DISCARD;
-   else if (rq->cmd_flags & REQ_WRITE)
+   else if (req_op(rq) == REQ_OP_WRITE)
op_type = OBJ_OP_WRITE;
else
op_type = OBJ_OP_READ;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 52963a2..6fd1601 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -844,7 +844,8 @@ static int blkif_queue_request(struct request *req, struct 
blkfront_ring_info *r
if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED))
return 1;
 
-   if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE)))
+   if (unlikely(req_op(req) == REQ_OP_DISCARD ||
+req->cmd_flags & REQ_SECURE))
return blkif_queue_discard_req(req, rinfo);
else
return blkif_queue_rw_req(req, rinfo);
@@ -2054,8 +2055,9 @@ static int blkif_recover(struct blkfront_info *info)
/*
 * Get the bios in the request so we can re-queue them.
 */
-   if (copy[i].request->cmd_flags &
-   (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
+   if (copy[i].request->cmd_flags & REQ_FLUSH ||
+   req_op(copy[i].request) == REQ_OP_DISCARD ||
+   copy[i].request->cmd_flags & (REQ_FUA | 
REQ_SECURE)) {
/*
 * Flush operations don't