[PATCH v4 1/2] filelock: use a consume fence in locks_inode_context()

[Mateusz Guzik]

Matches the idiom of storing a pointer with a release fence and safely
getting the content with a consume fence after.

Eliminates an actual fence on some archs.

Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
---
 include/linux/filelock.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/filelock.h b/include/linux/filelock.h
index 54b824c05299..dc15f5427680 100644
--- a/include/linux/filelock.h
+++ b/include/linux/filelock.h
@@ -241,7 +241,10 @@ bool locks_owner_has_blockers(struct file_lock_context *flctx,
 static inline struct file_lock_context *
 locks_inode_context(const struct inode *inode)
 {
-	return smp_load_acquire(&inode->i_flctx);
+	/*
+	 * Paired with the fence in locks_get_lock_context().
+	 */
+	return READ_ONCE(inode->i_flctx);
 }
 
 #else /* !CONFIG_FILE_LOCKING */
-- 
2.48.1