linux-ext4 - [PATCH 04/10] ext4: Use folio_next

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Message-ID: <20251024170822.1427218-5-willy@infradead.org>
Date: Fri, 24 Oct 2025 18:08:12 +0100
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: linux-fsdevel@...r.kernel.org,
	Christian Brauner <brauner@...nel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Theodore Ts'o <tytso@....edu>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	linux-ext4@...r.kernel.org
Subject: [PATCH 04/10] ext4: Use folio_next_pos()

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@...radead.org>
Cc: Theodore Ts'o <tytso@....edu>
Cc: Andreas Dilger <adilger.kernel@...ger.ca>
Cc: linux-ext4@...r.kernel.org
---
 fs/ext4/inode.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e99306a8f47c..1b22e9516db4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1319,8 +1319,8 @@ static int ext4_write_begin(const struct kiocb *iocb,
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
 
-	if (pos + len > folio_pos(folio) + folio_size(folio))
-		len = folio_pos(folio) + folio_size(folio) - pos;
+	if (len > folio_next_pos(folio) - pos)
+		len = folio_next_pos(folio) - pos;
 
 	from = offset_in_folio(folio, pos);
 	to = from + len;
@@ -2704,7 +2704,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
 
 			if (mpd->map.m_len == 0)
 				mpd->start_pos = folio_pos(folio);
-			mpd->next_pos = folio_pos(folio) + folio_size(folio);
+			mpd->next_pos = folio_next_pos(folio);
 			/*
 			 * Writeout when we cannot modify metadata is simple.
 			 * Just submit the page. For data=journal mode we
@@ -3146,8 +3146,8 @@ static int ext4_da_write_begin(const struct kiocb *iocb,
 	if (IS_ERR(folio))
 		return PTR_ERR(folio);
 
-	if (pos + len > folio_pos(folio) + folio_size(folio))
-		len = folio_pos(folio) + folio_size(folio) - pos;
+	if (len > folio_next_pos(folio) - pos)
+		len = folio_next_pos(folio) - pos;
 
 	ret = ext4_block_write_begin(NULL, folio, pos, len,
 				     ext4_da_get_block_prep);
-- 
2.47.2