rbd: set max_segments to USHRT_MAX

Commit 22b182825e9d ("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.

Cc: stable@vger.kernel.org
Fixes: 22b182825e9d ("rbd: bump queue_max_segments")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index aacae6f7163eed3a4935fcd53b397caad3b67a11..cc93522a6d419dc77902bab085306c2b316f6c16 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4387,7 +4387,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
        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);