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

[Miquel Raynal]

On Tue, 2021-06-15 at 09:39:05 UTC, Zhihao Cheng wrote:
> 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 at huawei.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes, thanks.

Miquel