Patchwork [5/8] nbd: use generic helper to set max_discard_sectors

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Submitter NamJae Jeon
Date April 13, 2013, 1:39 p.m.
Message ID <1365860358-21363-1-git-send-email-linkinjeon@gmail.com>
Download mbox | patch
Permalink /patch/236351/
State New
Headers show

Comments

NamJae Jeon - April 13, 2013, 1:39 p.m.
From: Namjae Jeon <namjae.jeon@samsung.com>

It is better to use blk_queue_max_discard_sectors helper
function to set max_discard_sectors as it checks
max_discard_sectors upper limit UINT_MAX >> 9

similar issue was reported for mmc in below link
https://lkml.org/lkml/2013/4/1/292

If multiple discard requests get merged, merged discard request's
size exceeds 4GB, there is possibility that merged discard request's
__data_len field may overflow.

This patch fixes this issue.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Vivek Trivedi <t.vivek@samsung.com>
---
 drivers/block/nbd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 7fecc78..0a081bc 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -854,7 +854,7 @@  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;
+		blk_queue_max_discard_sectors(disk->queue, UINT_MAX >> 9);
 		disk->queue->limits.discard_zeroes_data = 0;
 	}