rbd: set max_segments to USHRT_MAX

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>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index b0b6f52e030742ad8045cf0afda1b66f2c3dcb83..609227211295a432315e165618f5e456c5b8b597 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4421,7 +4421,7 @@ 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);