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authorJeff Dike <jdike@addtoit.com>2007-07-15 23:38:58 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2007-08-09 14:27:41 -0700
commit37ed1c7082cb0af655d9f7ab5aca8c97c5150609 (patch)
tree37488c32b539fd7d37140d98a305afd18c61e282
parented173ab97b4faeeb2809a81c2fa0e6e4f979d5bb (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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/um/drivers/ubd_kern.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 2e09f162c42f..c6acc1a3968c 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]);
if(err){
*error_out = "Failed to register device";