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-rw-r--r--kernel/fs/notify/fsnotify.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/fs/notify/fsnotify.c b/kernel/fs/notify/fsnotify.c
index dd3fb0b17..db39de2dd 100644
--- a/kernel/fs/notify/fsnotify.c
+++ b/kernel/fs/notify/fsnotify.c
@@ -26,7 +26,6 @@
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
-#include "../mount.h"
/*
* Clear all of the marks on an inode when it is being evicted from core
@@ -205,6 +204,16 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
mnt = NULL;
/*
+ * Optimization: srcu_read_lock() has a memory barrier which can
+ * be expensive. It protects walking the *_fsnotify_marks lists.
+ * However, if we do not walk the lists, we do not have to do
+ * SRCU because we have no references to any objects and do not
+ * need SRCU to keep them "alive".
+ */
+ if (hlist_empty(&to_tell->i_fsnotify_marks) &&
+ (!mnt || hlist_empty(&mnt->mnt_fsnotify_marks)))
+ return 0;
+ /*
* if this is a modify event we may need to clear the ignored masks
* otherwise return if neither the inode nor the vfsmount care about
* this type of event.