[PATCH 08/14] xfs: remove indirect calls from xfs_inode_walk{,_ag}

Darrick J. Wong
2021-06-02T00:53:18Z

From: Darrick J. Wong <djwong@kernel.org>

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>
---
fs/xfs/xfs_icache.c | 46 ++++++++++++++++++++++------------------------
1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 2e13e9347147..5c17bed8edb2 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -50,11 +50,9 @@ xfs_icwalk_tagged(enum xfs_icwalk_goal goal)
}

static int xfs_inode_walk(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_inode_walk_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);

/*
* Allocate and initialise an xfs_inode.
@@ -844,11 +842,11 @@ xfs_dqrele_all_inodes(
if (qflags & XFS_PQUOTA_ACCT)
eofb.eof_flags |= XFS_EOFB_DROP_PDQUOT;

- return xfs_inode_walk(mp, xfs_dqrele_inode, &eofb,
- XFS_ICWALK_DQRELE);
+ return xfs_inode_walk(mp, XFS_ICWALK_DQRELE, &eofb);
}
#else
# define xfs_dqrele_igrab(ip) (false)
+# define xfs_dqrele_inode(ip, priv) (0)
#endif /* CONFIG_XFS_QUOTA */

/*
@@ -1591,8 +1589,7 @@ xfs_blockgc_worker(

if (!sb_start_write_trylock(mp->m_super))
return;
- error = xfs_inode_walk_ag(pag, xfs_blockgc_scan_inode, NULL,
- XFS_ICWALK_BLOCKGC);
+ error = xfs_inode_walk_ag(pag, XFS_ICWALK_BLOCKGC, NULL);
if (error)
xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
pag->pag_agno, error);
@@ -1610,8 +1607,7 @@ xfs_blockgc_free_space(
{
trace_xfs_blockgc_free_space(mp, eofb, _RET_IP_);

- return xfs_inode_walk(mp, xfs_blockgc_scan_inode, eofb,
- XFS_ICWALK_BLOCKGC);
+ return xfs_inode_walk(mp, XFS_ICWALK_BLOCKGC, eofb);
}

/*
@@ -1698,15 +1694,14 @@ xfs_grabbed_for_walk(
}

/*
- * 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_inode_walk_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;
@@ -1777,7 +1772,14 @@ xfs_inode_walk_ag(
for (i = 0; i < nr_found; i++) {
if (!batch[i])
continue;
- error = execute(batch[i], args);
+ switch (goal) {
+ case XFS_ICWALK_DQRELE:
+ error = xfs_dqrele_inode(batch[i], args);
+ break;
+ case XFS_ICWALK_BLOCKGC:
+ error = xfs_blockgc_scan_inode(batch[i], args);
+ break;
+ }
xfs_irele(batch[i]);
if (error == -EAGAIN) {
skipped++;
@@ -1814,16 +1816,12 @@ xfs_inode_walk_get_perag(
return xfs_perag_get_tag(mp, agno, goal);
}

-/*
- * 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_inode_walk(
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;
@@ -1833,7 +1831,7 @@ xfs_inode_walk(
ag = 0;
while ((pag = xfs_inode_walk_get_perag(mp, ag, goal))) {
ag = pag->pag_agno + 1;
- error = xfs_inode_walk_ag(pag, execute, args, goal);
+ error = xfs_inode_walk_ag(pag, goal, args);
xfs_perag_put(pag);
if (error) {
last_error = error;