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[SCSI] mpt2sas: Fix for Driver oops, when loading driver with max_queue_depth command line option to a very small value 

If the specified max_queue_depth setting is less than the
expected number of internal commands, then driver will calculate
the queue depth size to a negitive number. This negitive number
is actually a very large number because variable is unsigned
16bit integer. So, the driver will ask for a very large amount of
memory for message frames and resulting into oops as memory
allocation routines will not able to handle such a large request.

So, in order to limit this kind of oops, The driver need to set
the max_queue_depth to a scsi mid layer's can_queue value. Then
the overall message frames required for IO is minimum of either
(max_queue_depth plus internal commands) or the IOC global
credits.

Signed-off-by: Sreekanth Reddy <sreekanth.reddy@lsi.com>
Cc: <stable@kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
sreekanth.reddy@lsi.com 2012-07-17 15:57:05 +05:30 committed by James Bottomley
parent 23dcfa61ba
commit 338b131a32
1 changed files with 8 additions and 5 deletions
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13
drivers/scsi/mpt2sas/mpt2sas_base.c
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@ -2424,10 +2424,13 @@ _base_allocate_memory_pools(struct MPT2SAS_ADAPTER *ioc, int sleep_flag)
}
/* command line tunables for max controller queue depth */
if (max_queue_depth != -1)
max_request_credit = (max_queue_depth < facts->RequestCredit)
? max_queue_depth : facts->RequestCredit;
else
if (max_queue_depth != -1 && max_queue_depth != 0) {
max_request_credit = min_t(u16, max_queue_depth +
ioc->hi_priority_depth + ioc->internal_depth,
facts->RequestCredit);
if (max_request_credit > MAX_HBA_QUEUE_DEPTH)
max_request_credit = MAX_HBA_QUEUE_DEPTH;
} else
max_request_credit = min_t(u16, facts->RequestCredit,
MAX_HBA_QUEUE_DEPTH);
@ -2502,7 +2505,7 @@ _base_allocate_memory_pools(struct MPT2SAS_ADAPTER *ioc, int sleep_flag)
/* set the scsi host can_queue depth
* with some internal commands that could be outstanding
*/
ioc->shost->can_queue = ioc->scsiio_depth - (2);
ioc->shost->can_queue = ioc->scsiio_depth;
dinitprintk(ioc, printk(MPT2SAS_INFO_FMT "scsi host: "
"can_queue depth (%d)\n", ioc->name, ioc->shost->can_queue));