Re: [PATCH 12/14] iomap: support ioends for direct reads

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

On Wed, Jan 14, 2026 at 08:41:10AM +0100, Christoph Hellwig wrote:
> Support using the ioend structure to defer I/O completion for
> direcvt reads in addition to writes.  This requires a check for the

  direct

> operation to not merge reads and writes in iomap_ioend_can_merge.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

...and I think this patchset wires up the first place the iomap ioend
code actually gets used for completions, right?

If the answer is 'yes' and with the typo fixed,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/iomap/ioend.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/fs/iomap/ioend.c b/fs/iomap/ioend.c
> index 86f44922ed3b..800d12f45438 100644
> --- a/fs/iomap/ioend.c
> +++ b/fs/iomap/ioend.c
> @@ -299,6 +299,14 @@ EXPORT_SYMBOL_GPL(iomap_finish_ioends);
>  static bool iomap_ioend_can_merge(struct iomap_ioend *ioend,
>  		struct iomap_ioend *next)
>  {
> +	/*
> +	 * There is no point in merging reads as there is no completion
> +	 * processing that can be easily batched up for them.
> +	 */
> +	if (bio_op(&ioend->io_bio) == REQ_OP_READ ||
> +	    bio_op(&next->io_bio) == REQ_OP_READ)
> +		return false;
> +
>  	if (ioend->io_bio.bi_status != next->io_bio.bi_status)
>  		return false;
>  	if (next->io_flags & IOMAP_IOEND_BOUNDARY)
> -- 
> 2.47.3
> 
>