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%3Ba=su...
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