4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gao Xiang <gaoxiang25@xxxxxxxxxx>
commit 948bbdb1818b7ad6e539dad4fbd2dd4650793ea9 upstream.
Just like other generic locks, insert a full barrier
in case of memory reorder.
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/erofs/internal.h | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -209,6 +209,11 @@ static inline bool erofs_workgroup_try_t
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();
}
