2013-04-19 16:42:32

by Namjae Jeon

[permalink] [raw]
Subject: [PATCH v2 8/9] dm thin: use generic helper to set max_discard_sectors

From: Namjae Jeon <[email protected]>

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

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 <[email protected]>
Signed-off-by: Vivek Trivedi <[email protected]>
drivers/md/dm-thin.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 905b75f..237295a 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2513,7 +2513,8 @@ static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
struct pool *pool = pt->pool;
struct queue_limits *data_limits;

- limits->max_discard_sectors = pool->sectors_per_block;
+ blk_queue_max_discard_sectors(bdev_get_queue(pt->data_dev->bdev),
+ pool->sectors_per_block);

* discard_granularity is just a hint, and not enforced.