[PATCH 18/22] fsnotify: Remove fsnotify_detach_group_marks()

From: Jan Kara <jack@suse.cz>
To: <linux-fsdevel@vger.kernel.org>
Cc: Amir Goldstein <amir73il@gmail.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Paul Moore <paul@paul-moore.com>, Jan Kara <jack@suse.cz>
Subject: [PATCH 18/22] fsnotify: Remove fsnotify_detach_group_marks()
Date: Fri, 20 Jan 2017 14:21:19 +0100	[thread overview]
Message-ID: <20170120132123.9670-19-jack@suse.cz> (raw)
In-Reply-To: <20170120132123.9670-1-jack@suse.cz>

The function is already mostly contained in what
fsnotify_clear_marks_by_group() does. Just update that function to not
select marks when all of them should be destroyed and remove
fsnotify_detach_group_marks().

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/notify/fsnotify.h             |  2 --
 fs/notify/group.c                |  9 +++++++-
 fs/notify/mark.c                 | 45 +++++++++-------------------------------
 include/linux/fsnotify_backend.h |  2 ++
 4 files changed, 20 insertions(+), 38 deletions(-)

diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
index cbb9df3b10d0..da28dc44b244 100644
--- a/fs/notify/fsnotify.h
+++ b/fs/notify/fsnotify.h
@@ -34,8 +34,6 @@ static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
 {
 	fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks);
 }
-/* prepare for freeing all marks associated with given group */
-extern void fsnotify_detach_group_marks(struct fsnotify_group *group);
 /* Wait until all marks queued for destruction are destroyed */
 extern void fsnotify_wait_marks_destroyed(void);
 
diff --git a/fs/notify/group.c b/fs/notify/group.c
index 79439cdf16e0..32357534de18 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -67,7 +67,14 @@ void fsnotify_destroy_group(struct fsnotify_group *group)
 	fsnotify_group_stop_queueing(group);
 
 	/* Clear all marks for this group and queue them for destruction */
-	fsnotify_detach_group_marks(group);
+	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_ALL_TYPES);
+
+	/*
+	 * Some marks can still be pinned when waiting for response from
+	 * userspace. Wait for those now. fsnotify_prepare_user_wait() will
+	 * not succeed now so this wait is race-free.
+	 */
+	wait_event(group->notification_waitq, !atomic_read(&group->user_waits));
 
 	/*
 	 * Wait until all marks get really destroyed. We could actually destroy
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 5eba0f4e9677..b0db0a24d177 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -67,7 +67,7 @@
  * - The fs the inode is on is unmounted.  (fsnotify_inode_delete/fsnotify_unmount_inodes)
  * - Something explicitly requests that it be removed.  (fsnotify_destroy_mark)
  * - The fsnotify_group associated with the mark is going away and all such marks
- *   need to be cleaned up. (fsnotify_detach_group_marks)
+ *   need to be cleaned up. (fsnotify_clear_marks_by_group)
  *
  * This has the very interesting property of being able to run concurrently with
  * any (or all) other directions.
@@ -636,7 +636,13 @@ void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
 {
 	struct fsnotify_mark *lmark, *mark;
 	LIST_HEAD(to_free);
+	struct list_head *head = &to_free;
 
+	/* Skip selection step if we want to clear all marks. */
+	if (type == FSNOTIFY_OBJ_ALL_TYPES) {
+		head = &group->marks_list;
+		goto clear;
+	}
 	/*
 	 * We have to be really careful here. Anytime we drop mark_mutex, e.g.
 	 * fsnotify_clear_marks_by_inode() can come and free marks. Even in our
@@ -653,13 +659,14 @@ void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
 	}
 	mutex_unlock(&group->mark_mutex);
 
+clear:
 	while (1) {
 		mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
-		if (list_empty(&to_free)) {
+		if (list_empty(head)) {
 			mutex_unlock(&group->mark_mutex);
 			break;
 		}
-		mark = list_first_entry(&to_free, struct fsnotify_mark, g_list);
+		mark = list_first_entry(head, struct fsnotify_mark, g_list);
 		fsnotify_get_mark(mark);
 		fsnotify_detach_mark(mark);
 		mutex_unlock(&group->mark_mutex);
@@ -668,38 +675,6 @@ void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
 	}
 }
 
-/*
- * Given a group, prepare for freeing all the marks associated with that group.
- * The marks are attached to the list of marks prepared for destruction, the
- * caller is responsible for freeing marks in that list after SRCU period has
- * ended.
- */
-void fsnotify_detach_group_marks(struct fsnotify_group *group)
-{
-	struct fsnotify_mark *mark;
-
-	while (1) {
-		mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
-		if (list_empty(&group->marks_list)) {
-			mutex_unlock(&group->mark_mutex);
-			break;
-		}
-		mark = list_first_entry(&group->marks_list,
-					struct fsnotify_mark, g_list);
-		fsnotify_get_mark(mark);
-		fsnotify_detach_mark(mark);
-		mutex_unlock(&group->mark_mutex);
-		fsnotify_free_mark(mark);
-		fsnotify_put_mark(mark);
-	}
-	/*
-	 * Some marks can still be pinned when waiting for response from
-	 * userspace. Wait for those now. fsnotify_prepare_user_wait() will
-	 * not succeed now so this wait is race-free.
-	 */
-	wait_event(group->notification_waitq, !atomic_read(&group->user_waits));
-}
-
 /* Destroy all marks attached to inode / vfsmount */
 void fsnotify_destroy_marks(struct fsnotify_mark_connector **connp)
 {
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 680b7e92101b..812b1b151020 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -206,6 +206,8 @@ struct fsnotify_mark_connector {
 	spinlock_t lock;
 #define FSNOTIFY_OBJ_TYPE_INODE		0x01
 #define FSNOTIFY_OBJ_TYPE_VFSMOUNT	0x02
+#define FSNOTIFY_OBJ_ALL_TYPES		(FSNOTIFY_OBJ_TYPE_INODE | \
+					 FSNOTIFY_OBJ_TYPE_VFSMOUNT)
 	unsigned int flags;	/* Type of object [lock] */
 	union {	/* Object pointer [lock] */
 		struct inode *inode;
-- 
2.10.2

