xfs: remove indirect calls from xfs_inode_walk{,_ag}

It turns out that there is a 1:1 mapping between the execute and goal
parameters that are passed to xfs_inode_walk_ag:

	xfs_blockgc_scan_inode <=> XFS_ICWALK_BLOCKGC
	xfs_dqrele_inode <=> XFS_ICWALK_DQRELE

Because of this exact correspondence, we don't need the execute function
pointer and can replace it with a direct call.

For the price of a forward static declaration, we can eliminate the
indirect function call.  This likely has a negligible impact on
performance (since the execute function runs transactions), but it also
simplifies the function signature.

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

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index b5ce958..5ca5bd2 100644 (file)
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -55,11 +55,9 @@ xfs_icwalk_tag(enum xfs_icwalk_goal goal)
 }
 
 static int xfs_icwalk(struct xfs_mount *mp,
-               int (*execute)(struct xfs_inode *ip, void *args),
-               void *args, enum xfs_icwalk_goal goal);
+               enum xfs_icwalk_goal goal, void *args);
 static int xfs_icwalk_ag(struct xfs_perag *pag,
-               int (*execute)(struct xfs_inode *ip, void *args),
-               void *args, enum xfs_icwalk_goal goal);
+               enum xfs_icwalk_goal goal, void *args);
 
 /*
  * Private inode cache walk flags for struct xfs_eofblocks.  Must not coincide
@@ -859,10 +857,11 @@ xfs_dqrele_all_inodes(
        if (qflags & XFS_PQUOTA_ACCT)
                eofb.eof_flags |= XFS_ICWALK_FLAG_DROP_PDQUOT;
 
-       return xfs_icwalk(mp, xfs_dqrele_inode, &eofb, XFS_ICWALK_DQRELE);
+       return xfs_icwalk(mp, XFS_ICWALK_DQRELE, &eofb);
 }
 #else
 # define xfs_dqrele_igrab(ip)          (false)
+# define xfs_dqrele_inode(ip, priv)    (0)
 #endif /* CONFIG_XFS_QUOTA */
 
 /*
@@ -1605,8 +1604,7 @@ xfs_blockgc_worker(
 
        if (!sb_start_write_trylock(mp->m_super))
                return;
-       error = xfs_icwalk_ag(pag, xfs_blockgc_scan_inode, NULL,
-                       XFS_ICWALK_BLOCKGC);
+       error = xfs_icwalk_ag(pag, XFS_ICWALK_BLOCKGC, NULL);
        if (error)
                xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
                                pag->pag_agno, error);
@@ -1624,8 +1622,7 @@ xfs_blockgc_free_space(
 {
        trace_xfs_blockgc_free_space(mp, eofb, _RET_IP_);
 
-       return xfs_icwalk(mp, xfs_blockgc_scan_inode, eofb,
-                       XFS_ICWALK_BLOCKGC);
+       return xfs_icwalk(mp, XFS_ICWALK_BLOCKGC, eofb);
 }
 
 /*
@@ -1716,16 +1713,36 @@ xfs_icwalk_igrab(
        }
 }
 
+/* Process an inode and release it.  Return -EAGAIN to skip an inode. */
+static inline int
+xfs_icwalk_process_inode(
+       enum xfs_icwalk_goal    goal,
+       struct xfs_inode        *ip,
+       void                    *args)
+{
+       int                     error;
+
+       switch (goal) {
+       case XFS_ICWALK_DQRELE:
+               error = xfs_dqrele_inode(ip, args);
+               break;
+       case XFS_ICWALK_BLOCKGC:
+               error = xfs_blockgc_scan_inode(ip, args);
+               break;
+       }
+       xfs_irele(ip);
+       return error;
+}
+
 /*
- * For a given per-AG structure @pag, grab, @execute, and rele all incore
- * inodes with the given radix tree @tag.
+ * For a given per-AG structure @pag and a goal, grab qualifying inodes and
+ * process them in some manner.
  */
 static int
 xfs_icwalk_ag(
        struct xfs_perag        *pag,
-       int                     (*execute)(struct xfs_inode *ip, void *args),
-       void                    *args,
-       enum xfs_icwalk_goal    goal)
+       enum xfs_icwalk_goal    goal,
+       void                    *args)
 {
        struct xfs_mount        *mp = pag->pag_mount;
        uint32_t                first_index;
@@ -1797,8 +1814,7 @@ restart:
                for (i = 0; i < nr_found; i++) {
                        if (!batch[i])
                                continue;
-                       error = execute(batch[i], args);
-                       xfs_irele(batch[i]);
+                       error = xfs_icwalk_process_inode(goal, batch[i], args);
                        if (error == -EAGAIN) {
                                skipped++;
                                continue;
@@ -1836,16 +1852,12 @@ xfs_icwalk_get_perag(
        return xfs_perag_get_tag(mp, agno, tag);
 }
 
-/*
- * Call the @execute function on all incore inodes matching the radix tree
- * @tag.
- */
+/* Walk all incore inodes to achieve a given goal. */
 static int
 xfs_icwalk(
        struct xfs_mount        *mp,
-       int                     (*execute)(struct xfs_inode *ip, void *args),
-       void                    *args,
-       enum xfs_icwalk_goal    goal)
+       enum xfs_icwalk_goal    goal,
+       void                    *args)
 {
        struct xfs_perag        *pag;
        int                     error = 0;
@@ -1854,7 +1866,7 @@ xfs_icwalk(
 
        while ((pag = xfs_icwalk_get_perag(mp, agno, goal))) {
                agno = pag->pag_agno + 1;
-               error = xfs_icwalk_ag(pag, execute, args, goal);
+               error = xfs_icwalk_ag(pag, goal, args);
                xfs_perag_put(pag);
                if (error) {
                        last_error = error;