Commit 8619b86f authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds

uml: limit request size on COWed devices

COWed devices can't handle more than 32 (64 on x86_64) sectors in one request
due to the size of the bitmap being carried around in the io_thread_req.

Enforce that by telling the block layer not to put too many sectors in
requests to COWed devices.
Signed-off-by: default avatarJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8234483
...@@ -712,6 +712,8 @@ static int ubd_add(int n, char **error_out) ...@@ -712,6 +712,8 @@ static int ubd_add(int n, char **error_out)
ubd_dev->queue->queuedata = ubd_dev; ubd_dev->queue->queuedata = ubd_dev;
blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG); blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
if(ubd_dev->cow.file != NULL)
blk_queue_max_sectors(ubd_dev->queue, 8 * sizeof(long));
err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]); err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){ if(err){
*error_out = "Failed to register device"; *error_out = "Failed to register device";
......
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