btrfs: split btrfs_set_lock_blocking_rw to read and write helpers
authorDavid Sterba <dsterba@suse.com>
Tue, 3 Apr 2018 23:43:05 +0000 (01:43 +0200)
committerDavid Sterba <dsterba@suse.com>
Mon, 25 Feb 2019 13:13:27 +0000 (14:13 +0100)
There are many callers that hardcode the desired lock type so we can
avoid the switch and call them directly. Split the current function to
two but leave a helper that still takes the variable lock type to make
current code compile.  The call sites will be converted in followup
patches.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/locking.c
fs/btrfs/locking.h

index 1da768e5ef75bda36142c084d6ba7c2b5c4bc809..7201d000f61d08e3e1e9c0d2d74529ec608777fc 100644 (file)
 
 static void btrfs_assert_tree_read_locked(struct extent_buffer *eb);
 
-/*
- * if we currently have a spinning reader or writer lock
- * (indicated by the rw flag) this will bump the count
- * of blocking holders and drop the spinlock.
- */
-void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
+void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
 {
        /*
-        * no lock is required.  The lock owner may change if
-        * we have a read lock, but it won't change to or away
-        * from us.  If we have the write lock, we are the owner
-        * and it'll never change.
+        * No lock is required.  The lock owner may change if we have a read
+        * lock, but it won't change to or away from us.  If we have the write
+        * lock, we are the owner and it'll never change.
         */
        if (eb->lock_nested && current->pid == eb->lock_owner)
                return;
-       if (rw == BTRFS_WRITE_LOCK) {
-               if (atomic_read(&eb->blocking_writers) == 0) {
-                       WARN_ON(atomic_read(&eb->spinning_writers) != 1);
-                       atomic_dec(&eb->spinning_writers);
-                       btrfs_assert_tree_locked(eb);
-                       atomic_inc(&eb->blocking_writers);
-                       write_unlock(&eb->lock);
-               }
-       } else if (rw == BTRFS_READ_LOCK) {
-               btrfs_assert_tree_read_locked(eb);
-               atomic_inc(&eb->blocking_readers);
-               WARN_ON(atomic_read(&eb->spinning_readers) == 0);
-               atomic_dec(&eb->spinning_readers);
-               read_unlock(&eb->lock);
+       btrfs_assert_tree_read_locked(eb);
+       atomic_inc(&eb->blocking_readers);
+       WARN_ON(atomic_read(&eb->spinning_readers) == 0);
+       atomic_dec(&eb->spinning_readers);
+       read_unlock(&eb->lock);
+}
+
+void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
+{
+       /*
+        * No lock is required.  The lock owner may change if we have a read
+        * lock, but it won't change to or away from us.  If we have the write
+        * lock, we are the owner and it'll never change.
+        */
+       if (eb->lock_nested && current->pid == eb->lock_owner)
+               return;
+       if (atomic_read(&eb->blocking_writers) == 0) {
+               WARN_ON(atomic_read(&eb->spinning_writers) != 1);
+               atomic_dec(&eb->spinning_writers);
+               btrfs_assert_tree_locked(eb);
+               atomic_inc(&eb->blocking_writers);
+               write_unlock(&eb->lock);
        }
 }
 
index 29135def468e97ab240ddf11d0c51c2555dbb5dc..0453a47976933202b48ee54a8682448202c3aac7 100644 (file)
@@ -17,7 +17,8 @@ void btrfs_tree_unlock(struct extent_buffer *eb);
 void btrfs_tree_read_lock(struct extent_buffer *eb);
 void btrfs_tree_read_unlock(struct extent_buffer *eb);
 void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
-void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw);
+void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
+void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
 void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw);
 void btrfs_assert_tree_locked(struct extent_buffer *eb);
 int btrfs_try_tree_read_lock(struct extent_buffer *eb);
@@ -37,6 +38,18 @@ static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
                BUG();
 }
 
+/*
+ * If we currently have a spinning reader or writer lock (indicated by the rw
+ * flag) this will bump the count of blocking holders and drop the spinlock.
+ */
+static inline void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
+{
+       if (rw == BTRFS_WRITE_LOCK)
+               btrfs_set_lock_blocking_write(eb);
+       else if (rw == BTRFS_READ_LOCK)
+               btrfs_set_lock_blocking_read(eb);
+}
+
 static inline void btrfs_set_lock_blocking(struct extent_buffer *eb)
 {
        btrfs_set_lock_blocking_rw(eb, BTRFS_WRITE_LOCK);