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7#include <linux/kthread.h>
8#include <linux/export.h>
9#include <linux/slab.h>
10#include <linux/workqueue.h>
11
12#include "usbip_common.h"
13
14struct usbip_event {
15 struct list_head node;
16 struct usbip_device *ud;
17};
18
19static DEFINE_SPINLOCK(event_lock);
20static LIST_HEAD(event_list);
21
22static void set_event(struct usbip_device *ud, unsigned long event)
23{
24 unsigned long flags;
25
26 spin_lock_irqsave(&ud->lock, flags);
27 ud->event |= event;
28 spin_unlock_irqrestore(&ud->lock, flags);
29}
30
31static void unset_event(struct usbip_device *ud, unsigned long event)
32{
33 unsigned long flags;
34
35 spin_lock_irqsave(&ud->lock, flags);
36 ud->event &= ~event;
37 spin_unlock_irqrestore(&ud->lock, flags);
38}
39
40static struct usbip_device *get_event(void)
41{
42 struct usbip_event *ue = NULL;
43 struct usbip_device *ud = NULL;
44 unsigned long flags;
45
46 spin_lock_irqsave(&event_lock, flags);
47 if (!list_empty(&event_list)) {
48 ue = list_first_entry(&event_list, struct usbip_event, node);
49 list_del(&ue->node);
50 }
51 spin_unlock_irqrestore(&event_lock, flags);
52
53 if (ue) {
54 ud = ue->ud;
55 kfree(ue);
56 }
57 return ud;
58}
59
60static struct task_struct *worker_context;
61
62static void event_handler(struct work_struct *work)
63{
64 struct usbip_device *ud;
65
66 if (worker_context == NULL) {
67 worker_context = current;
68 }
69
70 while ((ud = get_event()) != NULL) {
71 usbip_dbg_eh("pending event %lx\n", ud->event);
72
73 mutex_lock(&ud->sysfs_lock);
74
75
76
77
78 if (ud->event & USBIP_EH_SHUTDOWN) {
79 ud->eh_ops.shutdown(ud);
80 unset_event(ud, USBIP_EH_SHUTDOWN);
81 }
82
83
84 if (ud->event & USBIP_EH_RESET) {
85 ud->eh_ops.reset(ud);
86 unset_event(ud, USBIP_EH_RESET);
87 }
88
89
90 if (ud->event & USBIP_EH_UNUSABLE) {
91 ud->eh_ops.unusable(ud);
92 unset_event(ud, USBIP_EH_UNUSABLE);
93 }
94 mutex_unlock(&ud->sysfs_lock);
95
96 wake_up(&ud->eh_waitq);
97 }
98}
99
100int usbip_start_eh(struct usbip_device *ud)
101{
102 init_waitqueue_head(&ud->eh_waitq);
103 ud->event = 0;
104 return 0;
105}
106EXPORT_SYMBOL_GPL(usbip_start_eh);
107
108void usbip_stop_eh(struct usbip_device *ud)
109{
110 unsigned long pending = ud->event & ~USBIP_EH_BYE;
111
112 if (!(ud->event & USBIP_EH_BYE))
113 usbip_dbg_eh("usbip_eh stopping but not removed\n");
114
115 if (pending)
116 usbip_dbg_eh("usbip_eh waiting completion %lx\n", pending);
117
118 wait_event_interruptible(ud->eh_waitq, !(ud->event & ~USBIP_EH_BYE));
119 usbip_dbg_eh("usbip_eh has stopped\n");
120}
121EXPORT_SYMBOL_GPL(usbip_stop_eh);
122
123#define WORK_QUEUE_NAME "usbip_event"
124
125static struct workqueue_struct *usbip_queue;
126static DECLARE_WORK(usbip_work, event_handler);
127
128int usbip_init_eh(void)
129{
130 usbip_queue = create_singlethread_workqueue(WORK_QUEUE_NAME);
131 if (usbip_queue == NULL) {
132 pr_err("failed to create usbip_event\n");
133 return -ENOMEM;
134 }
135 return 0;
136}
137
138void usbip_finish_eh(void)
139{
140 flush_workqueue(usbip_queue);
141 destroy_workqueue(usbip_queue);
142 usbip_queue = NULL;
143}
144
145void usbip_event_add(struct usbip_device *ud, unsigned long event)
146{
147 struct usbip_event *ue;
148 unsigned long flags;
149
150 if (ud->event & USBIP_EH_BYE)
151 return;
152
153 set_event(ud, event);
154
155 spin_lock_irqsave(&event_lock, flags);
156
157 list_for_each_entry_reverse(ue, &event_list, node) {
158 if (ue->ud == ud)
159 goto out;
160 }
161
162 ue = kmalloc(sizeof(struct usbip_event), GFP_ATOMIC);
163 if (ue == NULL)
164 goto out;
165
166 ue->ud = ud;
167
168 list_add_tail(&ue->node, &event_list);
169 queue_work(usbip_queue, &usbip_work);
170
171out:
172 spin_unlock_irqrestore(&event_lock, flags);
173}
174EXPORT_SYMBOL_GPL(usbip_event_add);
175
176int usbip_event_happened(struct usbip_device *ud)
177{
178 int happened = 0;
179 unsigned long flags;
180
181 spin_lock_irqsave(&ud->lock, flags);
182 if (ud->event != 0)
183 happened = 1;
184 spin_unlock_irqrestore(&ud->lock, flags);
185
186 return happened;
187}
188EXPORT_SYMBOL_GPL(usbip_event_happened);
189
190int usbip_in_eh(struct task_struct *task)
191{
192 if (task == worker_context)
193 return 1;
194
195 return 0;
196}
197EXPORT_SYMBOL_GPL(usbip_in_eh);
198
