staging: erofs: add a full barrier in erofs_workgroup_unfreeze

Just like other generic locks, insert a full barrier
in case of memory reorder.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 399a7003e783eabdc4d0472220a05de8a94ec629..8929443558676263eb7ed1252a02fbad22f8ee9b 100644 (file)
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -209,6 +209,11 @@ static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
 static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
                                            int orig_val)
 {
+       /*
+        * other observers should notice all modifications
+        * in the freezing period.
+        */
+       smp_mb();
        atomic_set(&grp->refcount, orig_val);
        preempt_enable();
 }