xfs: define printk_once variants for xfs messages

There are a couple places where we directly call printk_once() and one
of them doesn't follow the standard xfs subsystem printk format as a
result.

#define printk_once variants to go with our existing printk_ratelimited
#defines so we can do one-shot printks in a consistent manner.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_message.h

@@ -40,6 +40,18 @@ do {									\
 		func(dev, fmt, ##__VA_ARGS__);				\
 } while (0)
 
+#define xfs_printk_once(func, dev, fmt, ...)			\
+({								\
+	static bool __section(.data.once) __print_once;		\
+	bool __ret_print_once = !__print_once; 			\
+								\
+	if (!__print_once) {					\
+		__print_once = true;				\
+		func(dev, fmt, ##__VA_ARGS__);			\
+	}							\
+	unlikely(__ret_print_once);				\
+})
+
 #define xfs_emerg_ratelimited(dev, fmt, ...)				\
 	xfs_printk_ratelimited(xfs_emerg, dev, fmt, ##__VA_ARGS__)
 #define xfs_alert_ratelimited(dev, fmt, ...)				\
@@ -57,6 +69,11 @@ do {									\
 #define xfs_debug_ratelimited(dev, fmt, ...)				\
 	xfs_printk_ratelimited(xfs_debug, dev, fmt, ##__VA_ARGS__)
 
+#define xfs_warn_once(dev, fmt, ...)				\
+	xfs_printk_once(xfs_warn, dev, fmt, ##__VA_ARGS__)
+#define xfs_notice_once(dev, fmt, ...)				\
+	xfs_printk_once(xfs_notice, dev, fmt, ##__VA_ARGS__)
+
 void assfail(struct xfs_mount *mp, char *expr, char *f, int l);
 void asswarn(struct xfs_mount *mp, char *expr, char *f, int l);
 

fs/xfs/xfs_mount.c

@@ -1300,10 +1300,9 @@ xfs_mod_fdblocks(
 		spin_unlock(&mp->m_sb_lock);
 		return 0;
 	}
-	printk_once(KERN_WARNING
-		"Filesystem \"%s\": reserve blocks depleted! "
-		"Consider increasing reserve pool size.",
-		mp->m_super->s_id);
+	xfs_warn_once(mp,
+"Reserve blocks depleted! Consider increasing reserve pool size.");
+
 fdblocks_enospc:
 	spin_unlock(&mp->m_sb_lock);
 	return -ENOSPC;

fs/xfs/xfs_pnfs.c

@@ -58,9 +58,8 @@ xfs_fs_get_uuid(
 {
 	struct xfs_mount	*mp = XFS_M(sb);
 
-	printk_once(KERN_NOTICE
-"XFS (%s): using experimental pNFS feature, use at your own risk!\n",
-		mp->m_super->s_id);
+	xfs_notice_once(mp,
+"Using experimental pNFS feature, use at your own risk!");
 
 	if (*len < sizeof(uuid_t))
 		return -EINVAL;