[PATCH] mtd: blkdevs: Fix mtd block write failure

[Brian Norris]

Hi,

On Sat, Aug 05, 2017 at 01:44:26AM +0530, Abhishek Sahu wrote:
> On 2017-08-03 20:40, Boris Brezillon wrote:
> >On Wed,  2 Aug 2017 18:03:05 +0530
> >Abhishek Sahu <absahu at codeaurora.org> wrote:
> >
> >>All the MTD block write requests are failing with
> >>following error messages
> >>
> >>    mkfs.ext4  /dev/mtdblock0
> >>
> >>    print_req_error: I/O error, dev mtdblock0, sector 0
> >>    Buffer I/O error on dev mtdblock0, logical block 0,
> >>    lost async page write
> >>
> >>The control is going to default case after block write request
> >>because of missing return.
> >>
> >>Fixes: commit 2a842acab109 ("block: introduce new block status
> >>code type")

Looks like that never even went to the MTD list. Oh well, I still likely
wouldn't have reviewed it this closely :)

> >>Signed-off-by: Abhishek Sahu <absahu at codeaurora.org>
> >
> >Acked-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> >
> 
>  Shall this patch be included for next RC since the MTD block
>  write is broken in 4.13 and without this, all the writes to
>  MTD block device will return failure.

Yes, applied to linux-mtd.git, and I'll try to get this out for 4.13.

> >>---
> >> 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 f336a9b..9ec8f03 100644
> >>--- a/drivers/mtd/mtd_blkdevs.c
> >>+++ b/drivers/mtd/mtd_blkdevs.c
> >>@@ -113,6 +113,7 @@ static blk_status_t
> >>do_blktrans_request(struct mtd_blktrans_ops *tr,
> >> 		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
> >> 			if (tr->writesect(dev, block, buf))
> >> 				return BLK_STS_IOERR;
> >>+		return BLK_STS_OK;

Ooh, that's a nasty one. No compiler warning, because it just falls back
to the 'default' case :(

Brian

> >> 	default:
> >> 		return BLK_STS_IOERR;
> >> 	}