[PATCH 28/32] fuse: remove fuse_mutex protection from fuse_dev_ioctl_sync_init()

[Miklos Szeredi <mszeredi@redhat.com>]

In normal use ioctl(FUSE_DEV_IOC_SYNC_INIT) comes before the mount() or
fsconfig() syscalls, they are executed strictly serially.

If ioctl and mount are performed in parallel, the behavior is
nondeterministic.  Removing the mutex does not change this.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/fuse/dev.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c59cbfd3ffee..5ebd6f3e0fe4 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2297,16 +2297,13 @@ static long fuse_dev_ioctl_backing_close(struct file *file, __u32 __user *argp)
 
 static long fuse_dev_ioctl_sync_init(struct file *file)
 {
-	int err = -EINVAL;
 	struct fuse_dev *fud = fuse_file_to_fud(file);
 
-	mutex_lock(&fuse_mutex);
-	if (!fuse_dev_chan_get(fud)) {
-		fud->sync_init = true;
-		err = 0;
-	}
-	mutex_unlock(&fuse_mutex);
-	return err;
+	if (fuse_dev_chan_get(fud))
+		return -EINVAL;
+
+	fud->sync_init = true;
+	return 0;
 }
 
 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
-- 
2.53.0