path: root/arch/um
diff options
authorJeff Dike <jdike@addtoit.com>2007-07-15 23:38:58 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:39 -0700
commit8619b86f20588c020b280e6f67a9b8712b1ee38a (patch)
treefb4c1d31ba40eb6b380fdf0fe956848edf93760f /arch/um
parente8234483e7545b3cd298b0265fcee2e4a14c9f51 (diff)
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: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um')
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 0947f2e2004..fc27f6c72b4 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -712,6 +712,8 @@ static int ubd_add(int n, char **error_out)
ubd_dev->queue->queuedata = ubd_dev;
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]);
*error_out = "Failed to register device";