git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 338b131a3269881c7431234855c93c219b0979b6 Mon Sep 17 00:00:00 2001
   2 From: "sreekanth.reddy@lsi.com" <sreekanth.reddy@lsi.com>
   3 Date: Tue, 17 Jul 2012 15:57:05 +0530
   4 Subject: SCSI: mpt2sas: Fix for Driver oops, when loading driver with max_queue_depth command line option to a very small value
   5
   6 From: "sreekanth.reddy@lsi.com" <sreekanth.reddy@lsi.com>
   7
   8 commit 338b131a3269881c7431234855c93c219b0979b6 upstream.
   9
  10 If the specified max_queue_depth setting is less than the
  11 expected number of internal commands, then driver will calculate
  12 the queue depth size to a negitive number. This negitive number
  13 is actually a very large number because variable is unsigned
  14 16bit integer. So, the driver will ask for a very large amount of
  15 memory for message frames and resulting into oops as memory
  16 allocation routines will not able to handle such a large request.
  17
  18 So, in order to limit this kind of oops, The driver need to set
  19 the max_queue_depth to a scsi mid layer's can_queue value. Then
  20 the overall message frames required for IO is minimum of either
  21 (max_queue_depth plus internal commands) or the IOC global
  22 credits.
  23
  24 Signed-off-by: Sreekanth Reddy <sreekanth.reddy@lsi.com>
  25 Signed-off-by: James Bottomley <JBottomley@Parallels.com>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27
  28 ---
  29  drivers/scsi/mpt2sas/mpt2sas_base.c |   13 ++++++++-----
  30  1 file changed, 8 insertions(+), 5 deletions(-)
  31
  32 --- a/drivers/scsi/mpt2sas/mpt2sas_base.c
  33 +++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
  34 @@ -2424,10 +2424,13 @@ _base_allocate_memory_pools(struct MPT2S
  35         }
  36
  37         /* command line tunables  for max controller queue depth */
  38 -       if (max_queue_depth != -1)
  39 -               max_request_credit = (max_queue_depth < facts->RequestCredit)
  40 -                   ? max_queue_depth : facts->RequestCredit;
  41 -       else
  42 +       if (max_queue_depth != -1 && max_queue_depth != 0) {
  43 +               max_request_credit = min_t(u16, max_queue_depth +
  44 +                       ioc->hi_priority_depth + ioc->internal_depth,
  45 +                       facts->RequestCredit);
  46 +               if (max_request_credit > MAX_HBA_QUEUE_DEPTH)
  47 +                       max_request_credit =  MAX_HBA_QUEUE_DEPTH;
  48 +       } else
  49                 max_request_credit = min_t(u16, facts->RequestCredit,
  50                     MAX_HBA_QUEUE_DEPTH);
  51
  52 @@ -2502,7 +2505,7 @@ _base_allocate_memory_pools(struct MPT2S
  53         /* set the scsi host can_queue depth
  54          * with some internal commands that could be outstanding
  55          */
  56 -       ioc->shost->can_queue = ioc->scsiio_depth - (2);
  57 +       ioc->shost->can_queue = ioc->scsiio_depth;
  58         dinitprintk(ioc, printk(MPT2SAS_INFO_FMT "scsi host: "
  59             "can_queue depth (%d)\n", ioc->name, ioc->shost->can_queue));
  60