xfs: pass the goal of the incore inode walk to xfs_inode_walk()

As part of removing the indirect calls and radix tag implementation
details from the incore inode walk loop, create an enum to represent the
goal of the inode iteration.  More immediately, this separate removes
the need for the "ICI_NOTAG" define which makes little sense.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_icache.c

@@ -26,12 +26,40 @@
 
 #include <linux/iversion.h>
 
+/* Radix tree tags for incore inode tree. */
+
+/* inode is to be reclaimed */
+#define XFS_ICI_RECLAIM_TAG	0
+/* Inode has speculative preallocations (posteof or cow) to clean. */
+#define XFS_ICI_BLOCKGC_TAG	1
+
+/*
+ * The goal for walking incore inodes.  These can correspond with incore inode
+ * radix tree tags when convenient.  Avoid existing XFS_IWALK namespace.
+ */
+enum xfs_icwalk_goal {
+	/* Goals that are not related to tags; these must be < 0. */
+	XFS_ICWALK_DQRELE	= -1,
+
+	/* Goals directly associated with tagged inodes. */
+	XFS_ICWALK_BLOCKGC	= XFS_ICI_BLOCKGC_TAG,
+};
+
+#define XFS_ICWALK_NULL_TAG	(-1U)
+
+/* Compute the inode radix tree tag for this goal. */
+static inline unsigned int
+xfs_icwalk_tag(enum xfs_icwalk_goal goal)
+{
+	return goal < 0 ? XFS_ICWALK_NULL_TAG : goal;
+}
+
 static int xfs_icwalk(struct xfs_mount *mp, int iter_flags,
 		int (*execute)(struct xfs_inode *ip, void *args),
-		void *args, int tag);
+		void *args, enum xfs_icwalk_goal goal);
 static int xfs_icwalk_ag(struct xfs_perag *pag, int iter_flags,
 		int (*execute)(struct xfs_inode *ip, void *args),
-		void *args, int tag);
+		void *args, enum xfs_icwalk_goal goal);
 
 /*
  * Private inode cache walk flags for struct xfs_eofblocks.  Must not coincide
@@ -791,7 +819,7 @@ xfs_dqrele_all_inodes(
 		eofb.eof_flags |= XFS_ICWALK_FLAG_DROP_PDQUOT;
 
 	return xfs_icwalk(mp, XFS_INODE_WALK_INEW_WAIT, xfs_dqrele_inode,
-			&eofb, XFS_ICI_NO_TAG);
+			&eofb, XFS_ICWALK_DQRELE);
 }
 #endif /* CONFIG_XFS_QUOTA */
 
@@ -1539,7 +1567,7 @@ xfs_blockgc_worker(
 	if (!sb_start_write_trylock(mp->m_super))
 		return;
 	error = xfs_icwalk_ag(pag, 0, xfs_blockgc_scan_inode, NULL,
-			XFS_ICI_BLOCKGC_TAG);
+			XFS_ICWALK_BLOCKGC);
 	if (error)
 		xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
 				pag->pag_agno, error);
@@ -1558,7 +1586,7 @@ xfs_blockgc_free_space(
 	trace_xfs_blockgc_free_space(mp, eofb, _RET_IP_);
 
 	return xfs_icwalk(mp, 0, xfs_blockgc_scan_inode, eofb,
-			XFS_ICI_BLOCKGC_TAG);
+			XFS_ICWALK_BLOCKGC);
 }
 
 /*
@@ -1639,7 +1667,7 @@ xfs_icwalk_ag(
 	int			iter_flags,
 	int			(*execute)(struct xfs_inode *ip, void *args),
 	void			*args,
-	int			tag)
+	enum xfs_icwalk_goal	goal)
 {
 	struct xfs_mount	*mp = pag->pag_mount;
 	uint32_t		first_index;
@@ -1655,12 +1683,13 @@ xfs_icwalk_ag(
 	nr_found = 0;
 	do {
 		struct xfs_inode *batch[XFS_LOOKUP_BATCH];
+		unsigned int	tag = xfs_icwalk_tag(goal);
 		int		error = 0;
 		int		i;
 
 		rcu_read_lock();
 
-		if (tag == XFS_ICI_NO_TAG)
+		if (tag == XFS_ICWALK_NULL_TAG)
 			nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
 					(void **)batch, first_index,
 					XFS_LOOKUP_BATCH);
@@ -1743,9 +1772,11 @@ static inline struct xfs_perag *
 xfs_icwalk_get_perag(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno,
-	int			tag)
+	enum xfs_icwalk_goal	goal)
 {
-	if (tag == XFS_ICI_NO_TAG)
+	unsigned int		tag = xfs_icwalk_tag(goal);
+
+	if (tag == XFS_ICWALK_NULL_TAG)
 		return xfs_perag_get(mp, agno);
 	return xfs_perag_get_tag(mp, agno, tag);
 }
@@ -1760,16 +1791,16 @@ xfs_icwalk(
 	int			iter_flags,
 	int			(*execute)(struct xfs_inode *ip, void *args),
 	void			*args,
-	int			tag)
+	enum xfs_icwalk_goal	goal)
 {
 	struct xfs_perag	*pag;
 	int			error = 0;
 	int			last_error = 0;
 	xfs_agnumber_t		agno = 0;
 
-	while ((pag = xfs_icwalk_get_perag(mp, agno, tag))) {
+	while ((pag = xfs_icwalk_get_perag(mp, agno, goal))) {
 		agno = pag->pag_agno + 1;
-		error = xfs_icwalk_ag(pag, iter_flags, execute, args, tag);
+		error = xfs_icwalk_ag(pag, iter_flags, execute, args, goal);
 		xfs_perag_put(pag);
 		if (error) {
 			last_error = error;

fs/xfs/xfs_icache.h

@@ -17,15 +17,6 @@ struct xfs_eofblocks {
 	__u64		eof_min_file_size;
 };
 
-/*
- * tags for inode radix tree
- */
-#define XFS_ICI_NO_TAG		(-1)	/* special flag for an untagged lookup
-					   in xfs_inode_walk */
-#define XFS_ICI_RECLAIM_TAG	0	/* inode is to be reclaimed */
-/* Inode has speculative preallocations (posteof or cow) to clean. */
-#define XFS_ICI_BLOCKGC_TAG	1
-
 /*
  * Flags for xfs_iget()
  */