[PATCH 03/52] fuse: rely on mutex_unlock() barrier instead of fput()

Vivek Goyal
2018-12-10T17:12:29Z

From: Stefan Hajnoczi <stefanha@redhat.com>

fput() will be moved out of this function in a later patch, so we cannot
rely on it as the memory barrier for ensuring file->private_data = fud
is visible.

Luckily there is a mutex_unlock() right before fput() which provides the
same effect.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
fs/fuse/inode.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 0b94b23b02d4..d08cd8bf7705 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1198,12 +1198,11 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
list_add_tail(&fc->entry, &fuse_conn_list);
sb->s_root = root_dentry;
file->private_data = fud;
- mutex_unlock(&fuse_mutex);
/*
- * atomic_dec_and_test() in fput() provides the necessary
- * memory barrier for file->private_data to be visible on all
- * CPUs after this
+ * mutex_unlock() provides the necessary memory barrier for
+ * file->private_data to be visible on all CPUs after this
*/
+ mutex_unlock(&fuse_mutex);
fput(file);

fuse_send_init(fc, init_req);
--
2.13.6