Re: [PATCH 3/3] iomap: use GFP_NOWAIT when application for iomap_dio_simple allocations

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Jul 23, 2026 at 07:01:41AM +0200, Christoph Hellwig wrote:
> For non-blocking iocbs we should avoid blocking allocation where
> possible, so switch to a GFP_NOWAIT allocation here.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/iomap/direct-io.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 36c976cf0848..5c28124b9f02 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -986,6 +986,7 @@ static void iomap_dio_simple_end_io(struct bio *bio)
>  ssize_t __iomap_dio_read_simple(struct kiocb *iocb, struct iov_iter *iter,
>  		struct iomap_iter *iomi)
>  {
> +	gfp_t gfp = (iomi->flags & IOMAP_NOWAIT) ? GFP_NOWAIT : GFP_KERNEL;
>  	struct iomap_dio_simple *sr;
>  	unsigned int alignment;
>  	struct bio *bio;
> @@ -1015,7 +1016,11 @@ ssize_t __iomap_dio_read_simple(struct kiocb *iocb, struct iov_iter *iter,
>  
>  	bio = bio_alloc_bioset(iomi->iomap.bdev,
>  			       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
> -			       REQ_OP_READ, GFP_KERNEL, &iomap_dio_simple_pool);
> +			       REQ_OP_READ, gfp, &iomap_dio_simple_pool);
> +	if (!bio) {
> +		ret = -EAGAIN;
> +		goto out_dio_end;
> +	}
>  	sr = container_of(bio, struct iomap_dio_simple, bio);
>  	sr->iocb = iocb;
>  	sr->dio_flags = 0;
> -- 
> 2.53.0
> 
>