Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / notify / group.c

diff --git a/kernel/fs/notify/group.c b/kernel/fs/notify/group.c
new file mode 100644 (file)
index 0000000..d16b62c
--- /dev/null
+++ b/kernel/fs/notify/group.c
@@ -0,0 +1,118 @@
+/*
+ *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2, or (at your option)
+ *  any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+#include <linux/rculist.h>
+#include <linux/wait.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+#include <linux/atomic.h>
+
+/*
+ * Final freeing of a group
+ */
+static void fsnotify_final_destroy_group(struct fsnotify_group *group)
+{
+       if (group->ops->free_group_priv)
+               group->ops->free_group_priv(group);
+
+       kfree(group);
+}
+
+/*
+ * Trying to get rid of a group. Remove all marks, flush all events and release
+ * the group reference.
+ * Note that another thread calling fsnotify_clear_marks_by_group() may still
+ * hold a ref to the group.
+ */
+void fsnotify_destroy_group(struct fsnotify_group *group)
+{
+       /* clear all inode marks for this group */
+       fsnotify_clear_marks_by_group(group);
+
+       synchronize_srcu(&fsnotify_mark_srcu);
+
+       /* clear the notification queue of all events */
+       fsnotify_flush_notify(group);
+
+       /*
+        * Destroy overflow event (we cannot use fsnotify_destroy_event() as
+        * that deliberately ignores overflow events.
+        */
+       if (group->overflow_event)
+               group->ops->free_event(group->overflow_event);
+
+       fsnotify_put_group(group);
+}
+
+/*
+ * Get reference to a group.
+ */
+void fsnotify_get_group(struct fsnotify_group *group)
+{
+       atomic_inc(&group->refcnt);
+}
+
+/*
+ * Drop a reference to a group.  Free it if it's through.
+ */
+void fsnotify_put_group(struct fsnotify_group *group)
+{
+       if (atomic_dec_and_test(&group->refcnt))
+               fsnotify_final_destroy_group(group);
+}
+
+/*
+ * Create a new fsnotify_group and hold a reference for the group returned.
+ */
+struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
+{
+       struct fsnotify_group *group;
+
+       group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
+       if (!group)
+               return ERR_PTR(-ENOMEM);
+
+       /* set to 0 when there a no external references to this group */
+       atomic_set(&group->refcnt, 1);
+       atomic_set(&group->num_marks, 0);
+
+       mutex_init(&group->notification_mutex);
+       INIT_LIST_HEAD(&group->notification_list);
+       init_waitqueue_head(&group->notification_waitq);
+       group->max_events = UINT_MAX;
+
+       mutex_init(&group->mark_mutex);
+       INIT_LIST_HEAD(&group->marks_list);
+
+       group->ops = ops;
+
+       return group;
+}
+
+int fsnotify_fasync(int fd, struct file *file, int on)
+{
+       struct fsnotify_group *group = file->private_data;
+
+       return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
+}