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-rw-r--r--fs/notify/mark.c66
-rw-r--r--include/linux/fsnotify_backend.h5
2 files changed, 53 insertions, 18 deletions
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index cfcbf114676e..fc0df4442f7b 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -92,6 +92,9 @@
#include "fsnotify.h"
struct srcu_struct fsnotify_mark_srcu;
+static DEFINE_SPINLOCK(destroy_lock);
+static LIST_HEAD(destroy_list);
+static DECLARE_WAIT_QUEUE_HEAD(destroy_waitq);
void fsnotify_get_mark(struct fsnotify_mark *mark)
{
@@ -165,19 +168,10 @@ void fsnotify_detach_mark(struct fsnotify_mark *mark)
atomic_dec(&group->num_marks);
}
-static void
-fsnotify_mark_free_rcu(struct rcu_head *rcu)
-{
- struct fsnotify_mark *mark;
-
- mark = container_of(rcu, struct fsnotify_mark, g_rcu);
- fsnotify_put_mark(mark);
-}
-
/*
- * Free fsnotify mark. The freeing is actually happening from a call_srcu
- * callback. Caller must have a reference to the mark or be protected by
- * fsnotify_mark_srcu.
+ * Free fsnotify mark. The freeing is actually happening from a kthread which
+ * first waits for srcu period end. Caller must have a reference to the mark
+ * or be protected by fsnotify_mark_srcu.
*/
void fsnotify_free_mark(struct fsnotify_mark *mark)
{
@@ -192,7 +186,10 @@ void fsnotify_free_mark(struct fsnotify_mark *mark)
mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
spin_unlock(&mark->lock);
- call_srcu(&fsnotify_mark_srcu, &mark->g_rcu, fsnotify_mark_free_rcu);
+ spin_lock(&destroy_lock);
+ list_add(&mark->g_list, &destroy_list);
+ spin_unlock(&destroy_lock);
+ wake_up(&destroy_waitq);
/*
* Some groups like to know that marks are being freed. This is a
@@ -388,7 +385,11 @@ err:
spin_unlock(&mark->lock);
- call_srcu(&fsnotify_mark_srcu, &mark->g_rcu, fsnotify_mark_free_rcu);
+ spin_lock(&destroy_lock);
+ list_add(&mark->g_list, &destroy_list);
+ spin_unlock(&destroy_lock);
+ wake_up(&destroy_waitq);
+
return ret;
}
@@ -491,3 +492,40 @@ void fsnotify_init_mark(struct fsnotify_mark *mark,
atomic_set(&mark->refcnt, 1);
mark->free_mark = free_mark;
}
+
+static int fsnotify_mark_destroy(void *ignored)
+{
+ struct fsnotify_mark *mark, *next;
+ struct list_head private_destroy_list;
+
+ for (;;) {
+ spin_lock(&destroy_lock);
+ /* exchange the list head */
+ list_replace_init(&destroy_list, &private_destroy_list);
+ spin_unlock(&destroy_lock);
+
+ synchronize_srcu(&fsnotify_mark_srcu);
+
+ list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
+ list_del_init(&mark->g_list);
+ fsnotify_put_mark(mark);
+ }
+
+ wait_event_interruptible(destroy_waitq, !list_empty(&destroy_list));
+ }
+
+ return 0;
+}
+
+static int __init fsnotify_mark_init(void)
+{
+ struct task_struct *thread;
+
+ thread = kthread_run(fsnotify_mark_destroy, NULL,
+ "fsnotify_mark");
+ if (IS_ERR(thread))
+ panic("unable to start fsnotify mark destruction thread.");
+
+ return 0;
+}
+device_initcall(fsnotify_mark_init);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 6b7e89f45aa4..533c4408529a 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -220,10 +220,7 @@ struct fsnotify_mark {
/* List of marks by group->i_fsnotify_marks. Also reused for queueing
* mark into destroy_list when it's waiting for the end of SRCU period
* before it can be freed. [group->mark_mutex] */
- union {
- struct list_head g_list;
- struct rcu_head g_rcu;
- };
+ struct list_head g_list;
/* Protects inode / mnt pointers, flags, masks */
spinlock_t lock;
/* List of marks for inode / vfsmount [obj_lock] */