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[1/4] Limit max_discard_sectors to UINT_MAX>>9

Message ID 1395791307-23727-2-git-send-email-gwendal@chromium.org (mailing list archive)
State New, archived
Headers show

Commit Message

Gwendal Grignou March 25, 2014, 11:48 p.m. UTC 
max_discard_sectors can not be larger than UINT_MAX>>9,
otherwise, there is a risk that discard requests would be merged
into a request larger than 4GB.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
---
 drivers/block/nbd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 2dc3b51..f30128b 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -859,7 +859,7 @@  static int __init nbd_init(void)
 		 */
 		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
 		disk->queue->limits.discard_granularity = 512;
-		disk->queue->limits.max_discard_sectors = UINT_MAX;
+		disk->queue->limits.max_discard_sectors = UINT_MAX >> 9;
 		disk->queue->limits.discard_zeroes_data = 0;
 		blk_queue_max_hw_sectors(disk->queue, 65536);
 		disk->queue->limits.max_sectors = 256;