Patch "rbd: set max_segments to USHRT_MAX" has been added to the 4.9-stable tree

Patch "rbd: set max_segments to USHRT_MAX" has been added to the 4.9-stable tree

[gregkh]

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

    rbd: set max_segments to USHRT_MAX

to the 4.9-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:
     rbd-set-max_segments-to-ushrt_max.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 21acdf45f4958135940f0b4767185cf911d4b010 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@gmail.com>
Date: Thu, 21 Dec 2017 15:35:11 +0100
Subject: rbd: set max_segments to USHRT_MAX

From: Ilya Dryomov <idryomov@gmail.com>

commit 21acdf45f4958135940f0b4767185cf911d4b010 upstream.

Commit d3834fefcfe5 ("rbd: bump queue_max_segments") bumped
max_segments (unsigned short) to max_hw_sectors (unsigned int).
max_hw_sectors is set to the number of 512-byte sectors in an object
and overflows unsigned short for 32M (largest possible) objects, making
the block layer resort to handing us single segment (i.e. single page
or even smaller) bios in that case.

Fixes: d3834fefcfe5 ("rbd: bump queue_max_segments")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/rbd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4511,7 +4511,7 @@ static int rbd_init_disk(struct rbd_devi
 	segment_size = rbd_obj_bytes(&rbd_dev->header);
 	blk_queue_max_hw_sectors(q, segment_size / SECTOR_SIZE);
 	q->limits.max_sectors = queue_max_hw_sectors(q);
-	blk_queue_max_segments(q, segment_size / SECTOR_SIZE);
+	blk_queue_max_segments(q, USHRT_MAX);
 	blk_queue_max_segment_size(q, segment_size);
 	blk_queue_io_min(q, segment_size);
 	blk_queue_io_opt(q, segment_size);


Patches currently in stable-queue which might be from idryomov@gmail.com are

queue-4.9/rbd-set-max_segments-to-ushrt_max.patch