[PATCH 07/10] iomap: Use folio_next_pos()

[PATCH 07/10] iomap: Use folio_next_pos()

[Matthew Wilcox (Oracle)]

This is one instruction more efficient than open-coding folio_pos() +
folio_size().  It's the equivalent of (x + y) << z rather than
x << z + y << z.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org
---
 fs/iomap/buffered-io.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8b847a1e27f1..32a27f36372d 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -707,7 +707,7 @@ static int __iomap_write_begin(const struct iomap_iter *iter,
 	 * are not changing pagecache contents.
 	 */
 	if (!(iter->flags & IOMAP_UNSHARE) && pos <= folio_pos(folio) &&
-	    pos + len >= folio_pos(folio) + folio_size(folio))
+	    pos + len >= folio_next_pos(folio))
 		return 0;
 
 	ifs = ifs_alloc(iter->inode, folio, iter->flags);
@@ -1097,8 +1097,7 @@ static void iomap_write_delalloc_ifs_punch(struct inode *inode,
 	if (!ifs)
 		return;
 
-	last_byte = min_t(loff_t, end_byte - 1,
-			folio_pos(folio) + folio_size(folio) - 1);
+	last_byte = min_t(loff_t, end_byte - 1, folio_next_pos(folio) - 1);
 	first_blk = offset_in_folio(folio, start_byte) >> blkbits;
 	last_blk = offset_in_folio(folio, last_byte) >> blkbits;
 	for (i = first_blk; i <= last_blk; i++) {
@@ -1129,8 +1128,7 @@ static void iomap_write_delalloc_punch(struct inode *inode, struct folio *folio,
 	 * Make sure the next punch start is correctly bound to
 	 * the end of this data range, not the end of the folio.
 	 */
-	*punch_start_byte = min_t(loff_t, end_byte,
-				folio_pos(folio) + folio_size(folio));
+	*punch_start_byte = min_t(loff_t, end_byte, folio_next_pos(folio));
 }
 
 /*
@@ -1170,7 +1168,7 @@ static void iomap_write_delalloc_scan(struct inode *inode,
 				start_byte, end_byte, iomap, punch);
 
 		/* move offset to start of next folio in range */
-		start_byte = folio_pos(folio) + folio_size(folio);
+		start_byte = folio_next_pos(folio);
 		folio_unlock(folio);
 		folio_put(folio);
 	}
-- 
2.47.2

Re: [PATCH 07/10] iomap: Use folio_next_pos()

[Darrick J. Wong]

On Fri, Oct 24, 2025 at 06:08:15PM +0100, Matthew Wilcox (Oracle) wrote:
> This is one instruction more efficient than open-coding folio_pos() +
> folio_size().  It's the equivalent of (x + y) << z rather than
> x << z + y << z.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: "Darrick J. Wong" <djwong@kernel.org>
> Cc: linux-xfs@vger.kernel.org

Looks like a nice win, even if a small one
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 8b847a1e27f1..32a27f36372d 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -707,7 +707,7 @@ static int __iomap_write_begin(const struct iomap_iter *iter,
>  	 * are not changing pagecache contents.
>  	 */
>  	if (!(iter->flags & IOMAP_UNSHARE) && pos <= folio_pos(folio) &&
> -	    pos + len >= folio_pos(folio) + folio_size(folio))
> +	    pos + len >= folio_next_pos(folio))
>  		return 0;
>  
>  	ifs = ifs_alloc(iter->inode, folio, iter->flags);
> @@ -1097,8 +1097,7 @@ static void iomap_write_delalloc_ifs_punch(struct inode *inode,
>  	if (!ifs)
>  		return;
>  
> -	last_byte = min_t(loff_t, end_byte - 1,
> -			folio_pos(folio) + folio_size(folio) - 1);
> +	last_byte = min_t(loff_t, end_byte - 1, folio_next_pos(folio) - 1);
>  	first_blk = offset_in_folio(folio, start_byte) >> blkbits;
>  	last_blk = offset_in_folio(folio, last_byte) >> blkbits;
>  	for (i = first_blk; i <= last_blk; i++) {
> @@ -1129,8 +1128,7 @@ static void iomap_write_delalloc_punch(struct inode *inode, struct folio *folio,
>  	 * Make sure the next punch start is correctly bound to
>  	 * the end of this data range, not the end of the folio.
>  	 */
> -	*punch_start_byte = min_t(loff_t, end_byte,
> -				folio_pos(folio) + folio_size(folio));
> +	*punch_start_byte = min_t(loff_t, end_byte, folio_next_pos(folio));
>  }
>  
>  /*
> @@ -1170,7 +1168,7 @@ static void iomap_write_delalloc_scan(struct inode *inode,
>  				start_byte, end_byte, iomap, punch);
>  
>  		/* move offset to start of next folio in range */
> -		start_byte = folio_pos(folio) + folio_size(folio);
> +		start_byte = folio_next_pos(folio);
>  		folio_unlock(folio);
>  		folio_put(folio);
>  	}
> -- 
> 2.47.2
> 

Re: [PATCH 07/10] iomap: Use folio_next_pos()

[Christoph Hellwig]

On Fri, Oct 24, 2025 at 06:08:15PM +0100, Matthew Wilcox (Oracle) wrote:
> This is one instruction more efficient than open-coding folio_pos() +
> folio_size().  It's the equivalent of (x + y) << z rather than
> x << z + y << z.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH 09/10] xfs: Use folio_next_pos()

[Matthew Wilcox (Oracle)]

This is one instruction more efficient than open-coding folio_pos() +
folio_size().  It's the equivalent of (x + y) << z rather than
x << z + y << z.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: linux-xfs@vger.kernel.org
---
 fs/xfs/scrub/xfarray.c | 2 +-
 fs/xfs/xfs_aops.c      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/scrub/xfarray.c b/fs/xfs/scrub/xfarray.c
index cdd13ed9c569..ed2e8c64b1a8 100644
--- a/fs/xfs/scrub/xfarray.c
+++ b/fs/xfs/scrub/xfarray.c
@@ -834,7 +834,7 @@ xfarray_sort_scan(
 		si->first_folio_idx = xfarray_idx(si->array,
 				folio_pos(si->folio) + si->array->obj_size - 1);
 
-		next_pos = folio_pos(si->folio) + folio_size(si->folio);
+		next_pos = folio_next_pos(si->folio);
 		si->last_folio_idx = xfarray_idx(si->array, next_pos - 1);
 		if (xfarray_pos(si->array, si->last_folio_idx + 1) > next_pos)
 			si->last_folio_idx--;
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index a26f79815533..ad76d5d01dd1 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -271,7 +271,7 @@ xfs_discard_folio(
 	 * folio itself and not the start offset that is passed in.
 	 */
 	xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, pos,
-				folio_pos(folio) + folio_size(folio), NULL);
+				folio_next_pos(folio), NULL);
 }
 
 /*
-- 
2.47.2

Re: [PATCH 09/10] xfs: Use folio_next_pos()

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>