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21#include <linux/fs.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/list.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mutex.h>
28#include <linux/namei.h>
29#include <linux/path.h>
30#include <linux/slab.h>
31#include <linux/spinlock.h>
32
33#include <linux/atomic.h>
34
35#include <linux/fsnotify_backend.h>
36#include "fsnotify.h"
37
38static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0);
39
40
41
42
43
44u32 fsnotify_get_cookie(void)
45{
46 return atomic_inc_return(&fsnotify_sync_cookie);
47}
48EXPORT_SYMBOL_GPL(fsnotify_get_cookie);
49
50void fsnotify_destroy_event(struct fsnotify_group *group,
51 struct fsnotify_event *event)
52{
53
54 if (!event || event == group->overflow_event)
55 return;
56
57
58
59
60
61
62 if (!list_empty(&event->list)) {
63 spin_lock(&group->notification_lock);
64 WARN_ON(!list_empty(&event->list));
65 spin_unlock(&group->notification_lock);
66 }
67 group->ops->free_event(event);
68}
69
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79
80
81int fsnotify_add_event(struct fsnotify_group *group,
82 struct fsnotify_event *event,
83 int (*merge)(struct fsnotify_group *,
84 struct fsnotify_event *),
85 void (*insert)(struct fsnotify_group *,
86 struct fsnotify_event *))
87{
88 int ret = 0;
89 struct list_head *list = &group->notification_list;
90
91 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
92
93 spin_lock(&group->notification_lock);
94
95 if (group->shutdown) {
96 spin_unlock(&group->notification_lock);
97 return 2;
98 }
99
100 if (event == group->overflow_event ||
101 group->q_len >= group->max_events) {
102 ret = 2;
103
104 if (!list_empty(&group->overflow_event->list)) {
105 spin_unlock(&group->notification_lock);
106 return ret;
107 }
108 event = group->overflow_event;
109 goto queue;
110 }
111
112 if (!list_empty(list) && merge) {
113 ret = merge(group, event);
114 if (ret) {
115 spin_unlock(&group->notification_lock);
116 return ret;
117 }
118 }
119
120queue:
121 group->q_len++;
122 list_add_tail(&event->list, list);
123 if (insert)
124 insert(group, event);
125 spin_unlock(&group->notification_lock);
126
127 wake_up(&group->notification_waitq);
128 kill_fasync(&group->fsn_fa, SIGIO, POLL_IN);
129 return ret;
130}
131
132void fsnotify_remove_queued_event(struct fsnotify_group *group,
133 struct fsnotify_event *event)
134{
135 assert_spin_locked(&group->notification_lock);
136
137
138
139
140 list_del_init(&event->list);
141 group->q_len--;
142}
143
144
145
146
147
148struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group)
149{
150 assert_spin_locked(&group->notification_lock);
151
152 if (fsnotify_notify_queue_is_empty(group))
153 return NULL;
154
155 return list_first_entry(&group->notification_list,
156 struct fsnotify_event, list);
157}
158
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160
161
162
163struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group)
164{
165 struct fsnotify_event *event = fsnotify_peek_first_event(group);
166
167 if (!event)
168 return NULL;
169
170 pr_debug("%s: group=%p event=%p\n", __func__, group, event);
171
172 fsnotify_remove_queued_event(group, event);
173
174 return event;
175}
176
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179
180
181void fsnotify_flush_notify(struct fsnotify_group *group)
182{
183 struct fsnotify_event *event;
184
185 spin_lock(&group->notification_lock);
186 while (!fsnotify_notify_queue_is_empty(group)) {
187 event = fsnotify_remove_first_event(group);
188 spin_unlock(&group->notification_lock);
189 fsnotify_destroy_event(group, event);
190 spin_lock(&group->notification_lock);
191 }
192 spin_unlock(&group->notification_lock);
193}
194