Btrfs: use wait_event instead of a single function

Since TASK_UNINTERRUPTIBLE has been used here, wait_event() can do the
same job.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 3 insertions, 18 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1d4f8a7a128c..95bd5336e85b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -609,23 +609,6 @@ fail_free:
         return ret;
 }
 
-static void btrfs_wait_for_no_snapshotting_writes(struct btrfs_root *root)
-{
-        s64 writers;
-        DEFINE_WAIT(wait);
-
-        do {
-                prepare_to_wait(&root->subv_writers->wait, &wait,
-                                TASK_UNINTERRUPTIBLE);
-
-                writers = percpu_counter_sum(&root->subv_writers->counter);
-                if (writers)
-                        schedule();
-
-        } while (writers);
-        finish_wait(&root->subv_writers->wait, &wait);
-}
-
 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
                            struct dentry *dentry,
                            u64 *async_transid, bool readonly,
@@ -654,7 +637,9 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 
         atomic_inc(&root->will_be_snapshotted);
         smp_mb__after_atomic();
-        btrfs_wait_for_no_snapshotting_writes(root);
+        /* wait for no snapshot writes */
+        wait_event(root->subv_writers->wait,
+                   percpu_counter_sum(&root->subv_writers->counter) == 0);
 
         ret = btrfs_start_delalloc_inodes(root, 0);
         if (ret)