Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fix from James Bottomley:
 "A single fix for machines with pages > 4k (PPC mostly).

  There's a bug in our optimal transfer size code where we don't account
  for pages > 4k and can set the transfer size to be less than the page
  size causing nasty failures"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  sd: Reject optimal transfer length smaller than page size

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 3d22fc3e3c1a..4e08d1cd704d 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2885,10 +2885,13 @@ static int sd_revalidate_disk(struct gendisk *disk)
 
         /*
          * Use the device's preferred I/O size for reads and writes
-         * unless the reported value is unreasonably large (or garbage).
+         * unless the reported value is unreasonably small, large, or
+         * garbage.
          */
-        if (sdkp->opt_xfer_blocks && sdkp->opt_xfer_blocks <= dev_max &&
-            sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS)
+        if (sdkp->opt_xfer_blocks &&
+            sdkp->opt_xfer_blocks <= dev_max &&
+            sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS &&
+            sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_CACHE_SIZE)
                 rw_max = q->limits.io_opt =
                         logical_to_sectors(sdp, sdkp->opt_xfer_blocks);
         else