[PATCH v2 3/9] sd: use generic helper to set max_discard_sectors

[Namjae Jeon]

From: Namjae Jeon <namjae.jeon at 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 at samsung.com>
Signed-off-by: Vivek Trivedi <t.vivek at samsung.com>
---
 drivers/scsi/sd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7992635..93c26b3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -632,7 +632,8 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
 		break;
 	}
 
-	q->limits.max_discard_sectors = max_blocks * (logical_block_size >> 9);
+	blk_queue_max_discard_sectors(q,
+				max_blocks * (logical_block_size >> 9));
 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 }
 
-- 
1.7.9.5