This is a note to let you know that I've just added the patch titled
sd: Fix maximum I/O size for BLOCK_PC requests
to the 4.1-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-maximum-i-o-size-for-block_pc-requests.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4f258a46346c03fa0bbb6199ffaf4e1f9f599660 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Date: Tue, 23 Jun 2015 12:13:59 -0400
Subject: sd: Fix maximum I/O size for BLOCK_PC requests
From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
commit 4f258a46346c03fa0bbb6199ffaf4e1f9f599660 upstream.
Commit bcdb247c6b6a ("sd: Limit transfer length") clamped the maximum
size of an I/O request to the MAXIMUM TRANSFER LENGTH field in the BLOCK
LIMITS VPD. This had the unfortunate effect of also limiting the maximum
size of non-filesystem requests sent to the device through sg/bsg.
Avoid using blk_queue_max_hw_sectors() and set the max_sectors queue
limit directly.
Also update the comment in blk_limits_max_hw_sectors() to clarify that
max_hw_sectors defines the limit for the I/O controller only.
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Reported-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
Tested-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-settings.c | 4 ++--
drivers/scsi/sd.c | 6 +++---
2 files changed, 5 insertions(+), 5 deletions(-)
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -241,8 +241,8 @@ EXPORT_SYMBOL(blk_queue_bounce_limit);
* Description:
* Enables a low level driver to set a hard upper limit,
* max_hw_sectors, on the size of requests. max_hw_sectors is set by
- * the device driver based upon the combined capabilities of I/O
- * controller and storage device.
+ * the device driver based upon the capabilities of the I/O
+ * controller.
*
* max_sectors is a soft limit imposed by the block layer for
* filesystem type requests. This value can be overridden on a
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2770,9 +2770,9 @@ static int sd_revalidate_disk(struct gen
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);
+ sdkp->disk->queue->limits.max_sectors =
+ min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), max_xfer);
+
set_capacity(disk, sdkp->capacity);
sd_config_write_same(sdkp);
kfree(buffer);
Patches currently in stable-queue which might be from martin.petersen@xxxxxxxxxx are
queue-4.1/sd-fix-maximum-i-o-size-for-block_pc-requests.patch
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