[10/43] xfs_repair: refactor offsetof+sizeof to offsetofend

Commit Message

Darrick J. Wong Oct. 11, 2024, 1:27 a.m. UTC

From: Darrick J. Wong <[e-mail]>

Replace this open-coded logic with the kernel's offsetofend macro before
we start adding more in the next patch.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 include/xfs.h     |   15 +++++++++++++++
 repair/agheader.c |   21 +++++++--------------
 2 files changed, 22 insertions(+), 14 deletions(-)

Patch

diff --git a/include/xfs.h b/include/xfs.h
index e97158c8d223f5..a2f159a586ee71 100644
--- a/include/xfs.h
+++ b/include/xfs.h
@@ -38,8 +38,23 @@  extern int xfs_assert_largefile[sizeof(off_t)-8];
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 #endif
 
+/**
+ * sizeof_field() - Report the size of a struct field in bytes
+ *
+ * @TYPE: The structure containing the field of interest
+ * @MEMBER: The field to return the size of
+ */
 #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
 
+/**
+ * offsetofend() - Report the offset of a struct field within the struct
+ *
+ * @TYPE: The type of the structure
+ * @MEMBER: The member within the structure to get the end offset of
+ */
+#define offsetofend(TYPE, MEMBER) \
+	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
+
 #include <xfs/xfs_types.h>
 /* Include deprecated/compat pre-vfs xfs-specific symbols */
 #include <xfs/xfs_fs_compat.h>
diff --git a/repair/agheader.c b/repair/agheader.c
index 5d4ca26cfb6155..daadacd1c43634 100644
--- a/repair/agheader.c
+++ b/repair/agheader.c
@@ -358,26 +358,19 @@  secondary_sb_whack(
 	 * size is the size of data which is valid for this sb.
 	 */
 	if (xfs_sb_version_hasmetadir(sb))
-		size = offsetof(struct xfs_dsb, sb_metadirino)
-			+ sizeof(sb->sb_metadirino);
+		size = offsetofend(struct xfs_dsb, sb_metadirino);
 	else if (xfs_sb_version_hasmetauuid(sb))
-		size = offsetof(struct xfs_dsb, sb_meta_uuid)
-			+ sizeof(sb->sb_meta_uuid);
+		size = offsetofend(struct xfs_dsb, sb_meta_uuid);
 	else if (xfs_sb_version_hascrc(sb))
-		size = offsetof(struct xfs_dsb, sb_lsn)
-			+ sizeof(sb->sb_lsn);
+		size = offsetofend(struct xfs_dsb, sb_lsn);
 	else if (xfs_sb_version_hasmorebits(sb))
-		size = offsetof(struct xfs_dsb, sb_bad_features2)
-			+ sizeof(sb->sb_bad_features2);
+		size = offsetofend(struct xfs_dsb, sb_bad_features2);
 	else if (xfs_sb_version_haslogv2(sb))
-		size = offsetof(struct xfs_dsb, sb_logsunit)
-			+ sizeof(sb->sb_logsunit);
+		size = offsetofend(struct xfs_dsb, sb_logsunit);
 	else if (xfs_sb_version_hassector(sb))
-		size = offsetof(struct xfs_dsb, sb_logsectsize)
-			+ sizeof(sb->sb_logsectsize);
+		size = offsetofend(struct xfs_dsb, sb_logsectsize);
 	else /* only support dirv2 or more recent */
-		size = offsetof(struct xfs_dsb, sb_dirblklog)
-			+ sizeof(sb->sb_dirblklog);
+		size = offsetofend(struct xfs_dsb, sb_dirblklog);
 
 	/* Check the buffer we read from disk for garbage outside size */
 	for (ip = (char *)sbuf->b_addr + size;