[PATCH 3/3] fs: Drop wait_unfrozen wait queue

["Darrick J. Wong" <djwong@kernel.org>]

From: Jan Kara <jack@suse.cz>

wait_unfrozen waitqueue is used only in quota code to wait for
filesystem to become unfrozen. In that place we can just use
sb_start_write() - sb_end_write() pair to achieve the same. So just
remove the waitqueue.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/quota/quota.c   |    5 +++--
 fs/super.c         |    4 ----
 include/linux/fs.h |    1 -
 3 files changed, 3 insertions(+), 7 deletions(-)


diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 052f143e2e0e..0e41fb84060f 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -895,8 +895,9 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
 			up_write(&sb->s_umount);
 		else
 			up_read(&sb->s_umount);
-		wait_event(sb->s_writers.wait_unfrozen,
-			   sb->s_writers.frozen == SB_UNFROZEN);
+		/* Wait for sb to unfreeze */
+		sb_start_write(sb);
+		sb_end_write(sb);
 		put_super(sb);
 		goto retry;
 	}
diff --git a/fs/super.c b/fs/super.c
index 151e0eeff2c2..fd04dda6c5c0 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -236,7 +236,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
 					&type->s_writers_key[i]))
 			goto fail;
 	}
-	init_waitqueue_head(&s->s_writers.wait_unfrozen);
 	s->s_bdi = &noop_backing_dev_info;
 	s->s_flags = flags;
 	if (s->s_user_ns != &init_user_ns)
@@ -1753,7 +1752,6 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 	if (ret) {
 		sb->s_writers.frozen = SB_UNFROZEN;
 		sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT);
-		wake_up(&sb->s_writers.wait_unfrozen);
 		wake_up_var(&sb->s_writers.frozen);
 		deactivate_locked_super(sb);
 		return ret;
@@ -1770,7 +1768,6 @@ int freeze_super(struct super_block *sb, enum freeze_holder who)
 				"VFS:Filesystem freeze failed\n");
 			sb->s_writers.frozen = SB_UNFROZEN;
 			sb_freeze_unlock(sb, SB_FREEZE_FS);
-			wake_up(&sb->s_writers.wait_unfrozen);
 			wake_up_var(&sb->s_writers.frozen);
 			deactivate_locked_super(sb);
 			return ret;
@@ -1853,7 +1850,6 @@ static int thaw_super_locked(struct super_block *sb, enum freeze_holder who)
 	wake_up_var(&sb->s_writers.frozen);
 	sb_freeze_unlock(sb, SB_FREEZE_FS);
 out:
-	wake_up(&sb->s_writers.wait_unfrozen);
 	deactivate_locked_super(sb);
 	return 0;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c58a560569b3..5870fbbecb81 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1147,7 +1147,6 @@ enum {
 struct sb_writers {
 	unsigned short			frozen;		/* Is sb frozen? */
 	unsigned short			freeze_holders;	/* Who froze fs? */
-	wait_queue_head_t		wait_unfrozen;	/* wait for thaw */
 	struct percpu_rw_semaphore	rw_sem[SB_FREEZE_LEVELS];
 };