quota: optimize i_dquot access

Remove redundant calls of i_dquot(), keep pointer in local variable.

add/remove: 0/0 grow/shrink: 3/7 up/down: 40/-278 (-238)
function                                     old     new   delta
__dquot_free_space                           734     750     +16
__dquot_alloc_space                          484     500     +16
dquot_free_inode                             324     332      +8
dquot_drop                                    82      69     -13
vfs_load_quota_inode                        1357    1341     -16
dquot_reclaim_space_nodirty                  348     316     -32
dquot_disable                               1980    1944     -36
dquot_claim_space_nodirty                    354     314     -40
__dquot_drop                                 125      83     -42
__dquot_initialize                           522     423     -99

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 39 insertions, 24 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 0ccd4ba3a246..2112ed33de41 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -900,14 +900,17 @@ static inline struct dquot **i_dquot(struct inode *inode)
 
 static int dqinit_needed(struct inode *inode, int type)
 {
+        struct dquot * const *dquots;
         int cnt;
 
         if (IS_NOQUOTA(inode))
                 return 0;
+
+        dquots = i_dquot(inode);
         if (type != -1)
-                return !i_dquot(inode)[type];
+                return !dquots[type];
         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
-                if (!i_dquot(inode)[cnt])
+                if (!dquots[cnt])
                         return 1;
         return 0;
 }
@@ -970,12 +973,13 @@ static void add_dquot_ref(struct super_block *sb, int type)
 static void remove_inode_dquot_ref(struct inode *inode, int type,
                                    struct list_head *tofree_head)
 {
-        struct dquot *dquot = i_dquot(inode)[type];
+        struct dquot **dquots = i_dquot(inode);
+        struct dquot *dquot = dquots[type];
 
-        i_dquot(inode)[type] = NULL;
         if (!dquot)
                 return;
 
+        dquots[type] = NULL;
         if (list_empty(&dquot->dq_free)) {
                 /*
                  * The inode still has reference to dquot so it can't be in the
@@ -1389,13 +1393,15 @@ static int dquot_active(const struct inode *inode)
 static void __dquot_initialize(struct inode *inode, int type)
 {
         int cnt, init_needed = 0;
-        struct dquot *got[MAXQUOTAS];
+        struct dquot **dquots, *got[MAXQUOTAS];
         struct super_block *sb = inode->i_sb;
         qsize_t rsv;
 
         if (!dquot_active(inode))
                 return;
 
+        dquots = i_dquot(inode);
+
         /* First get references to structures we might need. */
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                 struct kqid qid;
@@ -1407,7 +1413,7 @@ static void __dquot_initialize(struct inode *inode, int type)
                  * we check it without locking here to avoid unnecessary
                  * dqget()/dqput() calls.
                  */
-                if (i_dquot(inode)[cnt])
+                if (dquots[cnt])
                         continue;
                 init_needed = 1;
 
@@ -1438,8 +1444,8 @@ static void __dquot_initialize(struct inode *inode, int type)
                 /* We could race with quotaon or dqget() could have failed */
                 if (!got[cnt])
                         continue;
-                if (!i_dquot(inode)[cnt]) {
-                        i_dquot(inode)[cnt] = got[cnt];
+                if (!dquots[cnt]) {
+                        dquots[cnt] = got[cnt];
                         got[cnt] = NULL;
                         /*
                          * Make quota reservation system happy if someone
@@ -1447,7 +1453,7 @@ static void __dquot_initialize(struct inode *inode, int type)
                          */
                         rsv = inode_get_rsv_space(inode);
                         if (unlikely(rsv))
-                                dquot_resv_space(i_dquot(inode)[cnt], rsv);
+                                dquot_resv_space(dquots[cnt], rsv);
                 }
         }
 out_err:
@@ -1473,12 +1479,13 @@ EXPORT_SYMBOL(dquot_initialize);
 static void __dquot_drop(struct inode *inode)
 {
         int cnt;
+        struct dquot **dquots = i_dquot(inode);
         struct dquot *put[MAXQUOTAS];
 
         spin_lock(&dq_data_lock);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-                put[cnt] = i_dquot(inode)[cnt];
-                i_dquot(inode)[cnt] = NULL;
+                put[cnt] = dquots[cnt];
+                dquots[cnt] = NULL;
         }
         spin_unlock(&dq_data_lock);
         dqput_all(put);
@@ -1486,6 +1493,7 @@ static void __dquot_drop(struct inode *inode)
 
 void dquot_drop(struct inode *inode)
 {
+        struct dquot * const *dquots;
         int cnt;
 
         if (IS_NOQUOTA(inode))
@@ -1498,8 +1506,9 @@ void dquot_drop(struct inode *inode)
          * must assure that nobody can come after the DQUOT_DROP and
          * add quota pointers back anyway.
          */
+        dquots = i_dquot(inode);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-                if (i_dquot(inode)[cnt])
+                if (dquots[cnt])
                         break;
         }
 
@@ -1600,8 +1609,8 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
 {
         int cnt, ret = 0, index;
         struct dquot_warn warn[MAXQUOTAS];
-        struct dquot **dquots = i_dquot(inode);
         int reserve = flags & DQUOT_SPACE_RESERVE;
+        struct dquot **dquots;
 
         if (!dquot_active(inode)) {
                 inode_incr_space(inode, number, reserve);
@@ -1611,6 +1620,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                 warn[cnt].w_type = QUOTA_NL_NOWARN;
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
@@ -1652,13 +1662,14 @@ int dquot_alloc_inode(struct inode *inode)
 {
         int cnt, ret = 0, index;
         struct dquot_warn warn[MAXQUOTAS];
-        struct dquot * const *dquots = i_dquot(inode);
+        struct dquot * const *dquots;
 
         if (!dquot_active(inode))
                 return 0;
         for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                 warn[cnt].w_type = QUOTA_NL_NOWARN;
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
@@ -1690,6 +1701,7 @@ EXPORT_SYMBOL(dquot_alloc_inode);
  */
 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 {
+        struct dquot **dquots;
         int cnt, index;
 
         if (!dquot_active(inode)) {
@@ -1697,18 +1709,18 @@ int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
                 return 0;
         }
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         /* Claim reserved quotas to allocated quotas */
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-                if (i_dquot(inode)[cnt])
-                        dquot_claim_reserved_space(i_dquot(inode)[cnt],
-                                                        number);
+                if (dquots[cnt])
+                        dquot_claim_reserved_space(dquots[cnt], number);
         }
         /* Update inode bytes */
         inode_claim_rsv_space(inode, number);
         spin_unlock(&dq_data_lock);
-        mark_all_dquot_dirty(i_dquot(inode));
+        mark_all_dquot_dirty(dquots);
         srcu_read_unlock(&dquot_srcu, index);
         return 0;
 }
@@ -1719,6 +1731,7 @@ EXPORT_SYMBOL(dquot_claim_space_nodirty);
  */
 void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
 {
+        struct dquot **dquots;
         int cnt, index;
 
         if (!dquot_active(inode)) {
@@ -1726,18 +1739,18 @@ void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
                 return;
         }
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         /* Claim reserved quotas to allocated quotas */
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-                if (i_dquot(inode)[cnt])
-                        dquot_reclaim_reserved_space(i_dquot(inode)[cnt],
-                                                     number);
+                if (dquots[cnt])
+                        dquot_reclaim_reserved_space(dquots[cnt], number);
         }
         /* Update inode bytes */
         inode_reclaim_rsv_space(inode, number);
         spin_unlock(&dq_data_lock);
-        mark_all_dquot_dirty(i_dquot(inode));
+        mark_all_dquot_dirty(dquots);
         srcu_read_unlock(&dquot_srcu, index);
         return;
 }
@@ -1750,7 +1763,7 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
 {
         unsigned int cnt;
         struct dquot_warn warn[MAXQUOTAS];
-        struct dquot **dquots = i_dquot(inode);
+        struct dquot **dquots;
         int reserve = flags & DQUOT_SPACE_RESERVE, index;
 
         if (!dquot_active(inode)) {
@@ -1758,6 +1771,7 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
                 return;
         }
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
@@ -1793,12 +1807,13 @@ void dquot_free_inode(struct inode *inode)
 {
         unsigned int cnt;
         struct dquot_warn warn[MAXQUOTAS];
-        struct dquot * const *dquots = i_dquot(inode);
+        struct dquot * const *dquots;
         int index;
 
         if (!dquot_active(inode))
                 return;
 
+        dquots = i_dquot(inode);
         index = srcu_read_lock(&dquot_srcu);
         spin_lock(&dq_data_lock);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {