Re: [PATCH v5 03/10] iomap: refactor iomap_iter() length check and tracepoint

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

On Wed, Feb 05, 2025 at 08:58:14AM -0500, Brian Foster wrote:
> iomap_iter() checks iomap.length to skip individual code blocks not
> appropriate for the initial case where there is no mapping in the
> iter. To prepare for upcoming changes, refactor the code to jump
> straight to the ->iomap_begin() handler in the initial case and move
> the tracepoint to the top of the function so it always executes.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

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

--D

> ---
>  fs/iomap/iter.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c
> index 731ea7267f27..a2ae99fe6431 100644
> --- a/fs/iomap/iter.c
> +++ b/fs/iomap/iter.c
> @@ -73,7 +73,12 @@ int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops)
>  {
>  	int ret;
>  
> -	if (iter->iomap.length && ops->iomap_end) {
> +	trace_iomap_iter(iter, ops, _RET_IP_);
> +
> +	if (!iter->iomap.length)
> +		goto begin;
> +
> +	if (ops->iomap_end) {
>  		ret = ops->iomap_end(iter->inode, iter->pos, iomap_length(iter),
>  				iter->processed > 0 ? iter->processed : 0,
>  				iter->flags, &iter->iomap);
> @@ -82,14 +87,12 @@ int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops)
>  	}
>  
>  	/* advance and clear state from the previous iteration */
> -	trace_iomap_iter(iter, ops, _RET_IP_);
> -	if (iter->iomap.length) {
> -		ret = iomap_iter_advance(iter, iter->processed);
> -		iomap_iter_reset_iomap(iter);
> -		if (ret <= 0)
> -			return ret;
> -	}
> +	ret = iomap_iter_advance(iter, iter->processed);
> +	iomap_iter_reset_iomap(iter);
> +	if (ret <= 0)
> +		return ret;
>  
> +begin:
>  	ret = ops->iomap_begin(iter->inode, iter->pos, iter->len, iter->flags,
>  			       &iter->iomap, &iter->srcmap);
>  	if (ret < 0)
> -- 
> 2.48.1
> 
>