This is a note to let you know that I've just added the patch titled

    sd: Fix max transfer length for 4k disks

to the 3.18-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sd-fix-max-transfer-length-for-4k-disks.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 3a9794d32984b67a6d8992226918618f0e51e5d5 Mon Sep 17 00:00:00 2001
From: Brian King <[email protected]>
Date: Thu, 29 Jan 2015 15:54:40 -0600
Subject: sd: Fix max transfer length for 4k disks

From: Brian King <[email protected]>

commit 3a9794d32984b67a6d8992226918618f0e51e5d5 upstream.

The following patch fixes an issue observed with 4k sector disks
where the max_hw_sectors attribute was getting set too large in
sd_revalidate_disk. Since sdkp->max_xfer_blocks is in units
of SCSI logical blocks and queue_max_hw_sectors is in units of
512 byte blocks, on a 4k sector disk, every time we went through
sd_revalidate_disk, we were taking the current value of
queue_max_hw_sectors and increasing it by a factor of 8. Fix
this by only shifting sdkp->max_xfer_blocks.

Signed-off-by: Brian King <[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/scsi/sd.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2818,9 +2818,11 @@ static int sd_revalidate_disk(struct gen
         */
        sd_set_flush_flag(sdkp);
 
-       max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue),
-                               sdkp->max_xfer_blocks);
+       max_xfer = sdkp->max_xfer_blocks;
        max_xfer <<= ilog2(sdp->sector_size) - 9;
+
+       max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue),
+                               max_xfer);
        blk_queue_max_hw_sectors(sdkp->disk->queue, max_xfer);
        set_capacity(disk, sdkp->capacity);
        sd_config_write_same(sdkp);


Patches currently in stable-queue which might be from [email protected] 
are

queue-3.18/sd-fix-max-transfer-length-for-4k-disks.patch
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