xfs: constify the buffer pointer arguments to error functions

Some of the xfs error message functions take a pointer to a buffer that
will be dumped to the system log.  The logging functions don't change
the contents, so constify all the parameters.  This enables the next
patch to ensure that we log bad metadata when we encounter it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_error.c

@@ -329,7 +329,7 @@ xfs_corruption_error(
 	const char		*tag,
 	int			level,
 	struct xfs_mount	*mp,
-	void			*buf,
+	const void		*buf,
 	size_t			bufsize,
 	const char		*filename,
 	int			linenum,
@@ -350,7 +350,7 @@ xfs_buf_verifier_error(
 	struct xfs_buf		*bp,
 	int			error,
 	const char		*name,
-	void			*buf,
+	const void		*buf,
 	size_t			bufsz,
 	xfs_failaddr_t		failaddr)
 {
@@ -402,7 +402,7 @@ xfs_inode_verifier_error(
 	struct xfs_inode	*ip,
 	int			error,
 	const char		*name,
-	void			*buf,
+	const void		*buf,
 	size_t			bufsz,
 	xfs_failaddr_t		failaddr)
 {

fs/xfs/xfs_error.h

@@ -12,16 +12,16 @@ extern void xfs_error_report(const char *tag, int level, struct xfs_mount *mp,
 			const char *filename, int linenum,
 			xfs_failaddr_t failaddr);
 extern void xfs_corruption_error(const char *tag, int level,
-			struct xfs_mount *mp, void *buf, size_t bufsize,
+			struct xfs_mount *mp, const void *buf, size_t bufsize,
 			const char *filename, int linenum,
 			xfs_failaddr_t failaddr);
 extern void xfs_buf_verifier_error(struct xfs_buf *bp, int error,
-			const char *name, void *buf, size_t bufsz,
+			const char *name, const void *buf, size_t bufsz,
 			xfs_failaddr_t failaddr);
 extern void xfs_verifier_error(struct xfs_buf *bp, int error,
 			xfs_failaddr_t failaddr);
 extern void xfs_inode_verifier_error(struct xfs_inode *ip, int error,
-			const char *name, void *buf, size_t bufsz,
+			const char *name, const void *buf, size_t bufsz,
 			xfs_failaddr_t failaddr);
 
 #define	XFS_ERROR_REPORT(e, lvl, mp)	\

fs/xfs/xfs_message.c

@@ -105,7 +105,7 @@ assfail(char *expr, char *file, int line)
 }
 
 void
-xfs_hex_dump(void *p, int length)
+xfs_hex_dump(const void *p, int length)
 {
 	print_hex_dump(KERN_ALERT, "", DUMP_PREFIX_OFFSET, 16, 1, p, length, 1);
 }

fs/xfs/xfs_message.h

@@ -60,6 +60,6 @@ do {									\
 extern void assfail(char *expr, char *f, int l);
 extern void asswarn(char *expr, char *f, int l);
 
-extern void xfs_hex_dump(void *p, int length);
+extern void xfs_hex_dump(const void *p, int length);
 
 #endif	/* __XFS_MESSAGE_H */