Re: [PATCH 12/14] iomap: improve argument passing to iomap_read_folio_sync

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

On Tue, Jul 08, 2025 at 03:51:18PM +0200, Christoph Hellwig wrote:
> Pass the iomap_iter and derive the map inside iomap_read_folio_sync
> instead of in the caller, and use the more descriptive srcmap name for
> the source iomap.  Stop passing the offset into folio argument as it
> can be derived from the folio and the file offset.  Rename the
> variables for the offset into the file and the length to be more
> descriptive and match the rest of the code.
> 
> Rename the function itself to iomap_read_folio_range to make the use
> more clear.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Much clearer, thank you!
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index b04c00dd6768..c73048062cb1 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -657,22 +657,22 @@ iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
>  					 pos + len - 1);
>  }
>  
> -static int iomap_read_folio_sync(loff_t block_start, struct folio *folio,
> -		size_t poff, size_t plen, const struct iomap *iomap)
> +static int iomap_read_folio_range(const struct iomap_iter *iter,
> +		struct folio *folio, loff_t pos, size_t len)
>  {
> +	const struct iomap *srcmap = iomap_iter_srcmap(iter);
>  	struct bio_vec bvec;
>  	struct bio bio;
>  
> -	bio_init(&bio, iomap->bdev, &bvec, 1, REQ_OP_READ);
> -	bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
> -	bio_add_folio_nofail(&bio, folio, plen, poff);
> +	bio_init(&bio, srcmap->bdev, &bvec, 1, REQ_OP_READ);
> +	bio.bi_iter.bi_sector = iomap_sector(srcmap, pos);
> +	bio_add_folio_nofail(&bio, folio, len, offset_in_folio(folio, pos));
>  	return submit_bio_wait(&bio);
>  }
>  
>  static int __iomap_write_begin(const struct iomap_iter *iter, size_t len,
>  		struct folio *folio)
>  {
> -	const struct iomap *srcmap = iomap_iter_srcmap(iter);
>  	struct iomap_folio_state *ifs;
>  	loff_t pos = iter->pos;
>  	loff_t block_size = i_blocksize(iter->inode);
> @@ -721,8 +721,8 @@ static int __iomap_write_begin(const struct iomap_iter *iter, size_t len,
>  			if (iter->flags & IOMAP_NOWAIT)
>  				return -EAGAIN;
>  
> -			status = iomap_read_folio_sync(block_start, folio,
> -					poff, plen, srcmap);
> +			status = iomap_read_folio_range(iter, folio,
> +					block_start, plen);
>  			if (status)
>  				return status;
>  		}
> -- 
> 2.47.2
> 
>