APPLIED: [SRU][Groovy][PATCH] UBUNTU: SAUCE: Revert "block: don't ignore REQ_NOWAIT for direct IO"

[Kleber Souza]

On 09.07.21 21:03, Kamal Mostafa wrote:
> BugLink: https://bugs.launchpad.net/bugs/1935017
> 
> This reverts commit 87c9cfe0fa1fb0fc81c20a6f5ba3c2494871e061.
> 
> This commit which is a backport of
>    [mainline] f8b78caf21d5 "block: don't ignore REQ_NOWAIT for direct IO"
> was picked up from linux-stable v5.4 (or v5.10).  It has been shown to
> be the cause of the LP:#1935017 io_uring regression in the Ubuntu v5.8
> kernel (specifically observed in Ubuntu-hwe-5.8-5.8.0-59.66_20.04.1).
> 
> Reported-by: Juhyung Park <qkrwngud825 at gmail.com>
> Tested-by: Juhyung Park <qkrwngud825 at gmail.com>
> Signed-off-by: Kamal Mostafa <kamal at canonical.com>

Applied to groovy:linux.

Thanks,
Kleber

> ---
>   fs/block_dev.c | 4 ----
>   1 file changed, 4 deletions(-)
> 
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 271b05a321d0..0b6e300e938e 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -244,8 +244,6 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
>   		bio.bi_opf = dio_bio_write_op(iocb);
>   		task_io_account_write(ret);
>   	}
> -	if (iocb->ki_flags & IOCB_NOWAIT)
> -		bio.bi_opf |= REQ_NOWAIT;
>   	if (iocb->ki_flags & IOCB_HIPRI)
>   		bio_set_polled(&bio, iocb);
>   
> @@ -399,8 +397,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
>   			bio->bi_opf = dio_bio_write_op(iocb);
>   			task_io_account_write(bio->bi_iter.bi_size);
>   		}
> -		if (iocb->ki_flags & IOCB_NOWAIT)
> -			bio->bi_opf |= REQ_NOWAIT;
>   
>   		dio->size += bio->bi_iter.bi_size;
>   		pos += bio->bi_iter.bi_size;
>