[PATCH v2] mtd: mtd_blkdevs: Initialize rq.limits.discard_granularity

From: Zhihao Cheng
Date: Tue Jun 15 2021 - 05:30:29 EST


Since commit b35fd7422c2f8("block: check queue's limits.discard_granularity
in __blkdev_issue_discard()") checks rq.limits.discard_granularity in
__blkdev_issue_discard(), we may get following warnings on formatted ftl:

WARNING: CPU: 2 PID: 7313 at block/blk-lib.c:51
__blkdev_issue_discard+0x2a7/0x390

Reproducer:
1. ftl_format /dev/mtd0
2. modprobe ftl
3. mkfs.vfat /dev/ftla
4. mount -odiscard /dev/ftla temp
5. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct
6. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct

Fix it by initializing rq.limits.discard_granularity if device supports
discard operation.

Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
---
drivers/mtd/mtd_blkdevs.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 01bf234e7f3a..6eac1c9c164d 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -413,6 +413,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
if (tr->discard) {
blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
blk_queue_max_discard_sectors(new->rq, UINT_MAX);
+ new->rq->limits.discard_granularity = tr->blksize;
}

gd->queue = new->rq;
--
2.31.1