Re: [patch 20/23] aacraid driver fails with Dell PowerEdge Expandable RAID Controller 3/Di

[Miquel van Smoorenburg]

In article [EMAIL PROTECTED] you write:
Path: news.xs4all.nl!newsspool.news.xs4all.nl!post.news.xs4all.nl!gateway
The enclosed patch introduces a new adapter quirk and tries to limp
along by enabling pass-through in situations where memory is 32 bit
addressable on 64 bit machines, or disable the pass-through functions
altogether. I expect that the check for 32 bit addressable memory to be
controversial in that it can be incorrect in non-Dell non-Intel systems
that PERC would never be installed under, the alternative is to disable
pass-through in all cases which could be reported as another regression.

+static int aac_scsi_32_64(struct fib * fib, struct scsi_cmnd * cmd)
+{
+  if ((sizeof(dma_addr_t)  4) 
+   (num_physpages  (0xULL  PAGE_SHIFT)) 
+   (fib-dev-adapter_info.options  AAC_OPT_SGMAP_HOST64))
+  return FAILED;
+  return aac_scsi_32(fib, cmd);
+}

I saw the same thing in the 64-bit dpt_i2o driver, but I
wonder, shouldn't this be something like:

#include linux/bootmem.h

   if ((sizeof(dma_addr_t)  4) 
(max_pfn  (0xULL  PAGE_SHIFT)) 
(fib-dev-adapter_info.options  AAC_OPT_SGMAP_HOST64))

e.g. use max_pfn instead of num_physpages ?

Mike.
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RE: [patch 20/23] aacraid driver fails with Dell PowerEdge Expandable RAID Controller 3/Di

[Salyzyn, Mark]

 From: Miquel van Smoorenburg [mailto:[EMAIL PROTECTED] 
 +static int aac_scsi_32_64(struct fib * fib, struct scsi_cmnd * cmd)
 +{
 +if ((sizeof(dma_addr_t)  4) 
 + (num_physpages  (0xULL  PAGE_SHIFT)) 
 + (fib-dev-adapter_info.options  AAC_OPT_SGMAP_HOST64))
 +return FAILED;
 +return aac_scsi_32(fib, cmd);
 +}
 
 I saw the same thing in the 64-bit dpt_i2o driver, but I

Yes, scratch and sniff, caught me :-}

 wonder, shouldn't this be something like:
 
 #include linux/bootmem.h
 
if ((sizeof(dma_addr_t)  4) 
 (max_pfn  (0xULL  PAGE_SHIFT)) 
 (fib-dev-adapter_info.options  AAC_OPT_SGMAP_HOST64))
 
 e.g. use max_pfn instead of num_physpages ?

Yes, it would be more correct for the moment, save for the fact that it
is marked for deletion:

 * This doesn't seem to be used by the Linux memory manager any
 * more, but is used by ll_rw_block.  If we can get rid of it,
we
 * also get rid of some of the stuff above as well.
. . .
  max_pfn = . . .

and unfortunately architecture issues abound with all memory limit
variable :-(

in arch/arm/mm/init.c:

 * Note: max_low_pfn and max_pfn reflect the number of _pages_
in
 * the system, not the maximum PFN.

Reminder: If this automated solution represented in this patch, however
flawed with any memory limit variable, is too hacky and not acceptable
for inclusion, the workaround for the existing drivers and PERC users in
64 bit populated architectures continues to be to manually set
aacraid.dacmode=0 in the failing configurations.

What variable tells us the maximum physical memory address, is correct
in all architectures and is going to stick around? 

Sincerely -- Mark Salyzyn
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