1 files changed, 28 insertions, 34 deletions

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 2f6c3c7851ed..98fccce4208c 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -15,19 +15,19 @@
 #ifdef CONFIG_BTRFS_DEBUG
 static void btrfs_assert_spinning_writers_get(struct extent_buffer *eb)
 {
-        WARN_ON(atomic_read(&eb->spinning_writers));
-        atomic_inc(&eb->spinning_writers);
+        WARN_ON(eb->spinning_writers);
+        eb->spinning_writers++;
 }
 
 static void btrfs_assert_spinning_writers_put(struct extent_buffer *eb)
 {
-        WARN_ON(atomic_read(&eb->spinning_writers) != 1);
-        atomic_dec(&eb->spinning_writers);
+        WARN_ON(eb->spinning_writers != 1);
+        eb->spinning_writers--;
 }
 
 static void btrfs_assert_no_spinning_writers(struct extent_buffer *eb)
 {
-        WARN_ON(atomic_read(&eb->spinning_writers));
+        WARN_ON(eb->spinning_writers);
 }
 
 static void btrfs_assert_spinning_readers_get(struct extent_buffer *eb)
@@ -58,17 +58,17 @@ static void btrfs_assert_tree_read_locked(struct extent_buffer *eb)
 
 static void btrfs_assert_tree_write_locks_get(struct extent_buffer *eb)
 {
-        atomic_inc(&eb->write_locks);
+        eb->write_locks++;
 }
 
 static void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb)
 {
-        atomic_dec(&eb->write_locks);
+        eb->write_locks--;
 }
 
 void btrfs_assert_tree_locked(struct extent_buffer *eb)
 {
-        BUG_ON(!atomic_read(&eb->write_locks));
+        BUG_ON(!eb->write_locks);
 }
 
 #else
@@ -111,10 +111,10 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
          */
         if (eb->lock_nested && current->pid == eb->lock_owner)
                 return;
-        if (atomic_read(&eb->blocking_writers) == 0) {
+        if (eb->blocking_writers == 0) {
                 btrfs_assert_spinning_writers_put(eb);
                 btrfs_assert_tree_locked(eb);
-                atomic_inc(&eb->blocking_writers);
+                eb->blocking_writers++;
                 write_unlock(&eb->lock);
         }
 }
@@ -148,12 +148,11 @@ void btrfs_clear_lock_blocking_write(struct extent_buffer *eb)
          */
         if (eb->lock_nested && current->pid == eb->lock_owner)
                 return;
-        BUG_ON(atomic_read(&eb->blocking_writers) != 1);
         write_lock(&eb->lock);
+        BUG_ON(eb->blocking_writers != 1);
         btrfs_assert_spinning_writers_get(eb);
-        /* atomic_dec_and_test implies a barrier */
-        if (atomic_dec_and_test(&eb->blocking_writers))
-                cond_wake_up_nomb(&eb->write_lock_wq);
+        if (--eb->blocking_writers == 0)
+                cond_wake_up(&eb->write_lock_wq);
 }
 
 /*
@@ -167,12 +166,10 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
         if (trace_btrfs_tree_read_lock_enabled())
                 start_ns = ktime_get_ns();
 again:
-        BUG_ON(!atomic_read(&eb->blocking_writers) &&
-               current->pid == eb->lock_owner);
-
         read_lock(&eb->lock);
-        if (atomic_read(&eb->blocking_writers) &&
-            current->pid == eb->lock_owner) {
+        BUG_ON(eb->blocking_writers == 0 &&
+               current->pid == eb->lock_owner);
+        if (eb->blocking_writers && current->pid == eb->lock_owner) {
                 /*
                  * This extent is already write-locked by our thread. We allow
                  * an additional read lock to be added because it's for the same
@@ -185,10 +182,10 @@ again:
                 trace_btrfs_tree_read_lock(eb, start_ns);
                 return;
         }
-        if (atomic_read(&eb->blocking_writers)) {
+        if (eb->blocking_writers) {
                 read_unlock(&eb->lock);
                 wait_event(eb->write_lock_wq,
-                           atomic_read(&eb->blocking_writers) == 0);
+                           eb->blocking_writers == 0);
                 goto again;
         }
         btrfs_assert_tree_read_locks_get(eb);
@@ -203,11 +200,11 @@ again:
  */
 int btrfs_tree_read_lock_atomic(struct extent_buffer *eb)
 {
-        if (atomic_read(&eb->blocking_writers))
+        if (eb->blocking_writers)
                 return 0;
 
         read_lock(&eb->lock);
-        if (atomic_read(&eb->blocking_writers)) {
+        if (eb->blocking_writers) {
                 read_unlock(&eb->lock);
                 return 0;
         }
@@ -223,13 +220,13 @@ int btrfs_tree_read_lock_atomic(struct extent_buffer *eb)
  */
 int btrfs_try_tree_read_lock(struct extent_buffer *eb)
 {
-        if (atomic_read(&eb->blocking_writers))
+        if (eb->blocking_writers)
                 return 0;
 
         if (!read_trylock(&eb->lock))
                 return 0;
 
-        if (atomic_read(&eb->blocking_writers)) {
+        if (eb->blocking_writers) {
                 read_unlock(&eb->lock);
                 return 0;
         }
@@ -245,13 +242,11 @@ int btrfs_try_tree_read_lock(struct extent_buffer *eb)
  */
 int btrfs_try_tree_write_lock(struct extent_buffer *eb)
 {
-        if (atomic_read(&eb->blocking_writers) ||
-            atomic_read(&eb->blocking_readers))
+        if (eb->blocking_writers || atomic_read(&eb->blocking_readers))
                 return 0;
 
         write_lock(&eb->lock);
-        if (atomic_read(&eb->blocking_writers) ||
-            atomic_read(&eb->blocking_readers)) {
+        if (eb->blocking_writers || atomic_read(&eb->blocking_readers)) {
                 write_unlock(&eb->lock);
                 return 0;
         }
@@ -322,10 +317,9 @@ void btrfs_tree_lock(struct extent_buffer *eb)
         WARN_ON(eb->lock_owner == current->pid);
 again:
         wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0);
-        wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0);
+        wait_event(eb->write_lock_wq, eb->blocking_writers == 0);
         write_lock(&eb->lock);
-        if (atomic_read(&eb->blocking_readers) ||
-            atomic_read(&eb->blocking_writers)) {
+        if (atomic_read(&eb->blocking_readers) || eb->blocking_writers) {
                 write_unlock(&eb->lock);
                 goto again;
         }
@@ -340,7 +334,7 @@ again:
  */
 void btrfs_tree_unlock(struct extent_buffer *eb)
 {
-        int blockers = atomic_read(&eb->blocking_writers);
+        int blockers = eb->blocking_writers;
 
         BUG_ON(blockers > 1);
 
@@ -351,7 +345,7 @@ void btrfs_tree_unlock(struct extent_buffer *eb)
 
         if (blockers) {
                 btrfs_assert_no_spinning_writers(eb);
-                atomic_dec(&eb->blocking_writers);
+                eb->blocking_writers--;
                 /* Use the lighter barrier after atomic */
                 smp_mb__after_atomic();
                 cond_wake_up_nomb(&eb->write_lock_wq);