linux-kernel - [PATCH v4 1/3] fs/ufs: Use the offset_in

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Message-Id: <20221221172802.18743-2-fmdefrancesco@gmail.com>
Date:   Wed, 21 Dec 2022 18:28:00 +0100
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     Evgeniy Dushistov <dushistov@...l.ru>,
        Al Viro <viro@...iv.linux.org.uk>,
        Ira Weiny <ira.weiny@...el.com>, linux-kernel@...r.kernel.org,
        bpf@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Subject: [PATCH v4 1/3] fs/ufs: Use the offset_in_page() helper

Use the offset_in_page() helper because it is more suitable than doing
explicit subtractions between pointers to directory entries and kernel
virtual addresses of mapped pages.

Cc: Ira Weiny <ira.weiny@...el.com>
Suggested-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
---
 fs/ufs/dir.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/fs/ufs/dir.c b/fs/ufs/dir.c
index 391efaf1d528..69f78583c9c1 100644
--- a/fs/ufs/dir.c
+++ b/fs/ufs/dir.c
@@ -87,8 +87,7 @@ void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
 		  struct page *page, struct inode *inode,
 		  bool update_times)
 {
-	loff_t pos = page_offset(page) +
-			(char *) de - (char *) page_address(page);
+	loff_t pos = page_offset(page) + offset_in_page(de);
 	unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
 	int err;
 
@@ -371,8 +370,7 @@ int ufs_add_link(struct dentry *dentry, struct inode *inode)
 	return -EINVAL;
 
 got_it:
-	pos = page_offset(page) +
-			(char*)de - (char*)page_address(page);
+	pos = page_offset(page) + offset_in_page(de);
 	err = ufs_prepare_chunk(page, pos, rec_len);
 	if (err)
 		goto out_unlock;
@@ -497,8 +495,8 @@ int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
 {
 	struct super_block *sb = inode->i_sb;
 	char *kaddr = page_address(page);
-	unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
-	unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen);
+	unsigned int from = offset_in_page(dir) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
+	unsigned int to = offset_in_page(dir) + fs16_to_cpu(sb, dir->d_reclen);
 	loff_t pos;
 	struct ufs_dir_entry *pde = NULL;
 	struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
@@ -522,7 +520,7 @@ int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
 		de = ufs_next_entry(sb, de);
 	}
 	if (pde)
-		from = (char*)pde - (char*)page_address(page);
+		from = offset_in_page(pde);
 
 	pos = page_offset(page) + from;
 	lock_page(page);
-- 
2.39.0