1 /*
2 * Copyright (C) 2003-2008 Takahiro Hirofuchi
3 *
4 * This is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
17 * USA.
18 */
19
20 #include <linux/kthread.h>
21 #include <linux/export.h>
22
23 #include "usbip_common.h"
24
event_handler(struct usbip_device * ud)25 static int event_handler(struct usbip_device *ud)
26 {
27 usbip_dbg_eh("enter\n");
28
29 /*
30 * Events are handled by only this thread.
31 */
32 while (usbip_event_happened(ud)) {
33 usbip_dbg_eh("pending event %lx\n", ud->event);
34
35 /*
36 * NOTE: shutdown must come first.
37 * Shutdown the device.
38 */
39 if (ud->event & USBIP_EH_SHUTDOWN) {
40 ud->eh_ops.shutdown(ud);
41 ud->event &= ~USBIP_EH_SHUTDOWN;
42 }
43
44 /* Reset the device. */
45 if (ud->event & USBIP_EH_RESET) {
46 ud->eh_ops.reset(ud);
47 ud->event &= ~USBIP_EH_RESET;
48 }
49
50 /* Mark the device as unusable. */
51 if (ud->event & USBIP_EH_UNUSABLE) {
52 ud->eh_ops.unusable(ud);
53 ud->event &= ~USBIP_EH_UNUSABLE;
54 }
55
56 /* Stop the error handler. */
57 if (ud->event & USBIP_EH_BYE)
58 return -1;
59 }
60
61 return 0;
62 }
63
event_handler_loop(void * data)64 static int event_handler_loop(void *data)
65 {
66 struct usbip_device *ud = data;
67
68 while (!kthread_should_stop()) {
69 wait_event_interruptible(ud->eh_waitq,
70 usbip_event_happened(ud) ||
71 kthread_should_stop());
72 usbip_dbg_eh("wakeup\n");
73
74 if (event_handler(ud) < 0)
75 break;
76 }
77
78 return 0;
79 }
80
usbip_start_eh(struct usbip_device * ud)81 int usbip_start_eh(struct usbip_device *ud)
82 {
83 init_waitqueue_head(&ud->eh_waitq);
84 ud->event = 0;
85
86 ud->eh = kthread_run(event_handler_loop, ud, "usbip_eh");
87 if (IS_ERR(ud->eh)) {
88 pr_warning("Unable to start control thread\n");
89 return PTR_ERR(ud->eh);
90 }
91
92 return 0;
93 }
94 EXPORT_SYMBOL_GPL(usbip_start_eh);
95
usbip_stop_eh(struct usbip_device * ud)96 void usbip_stop_eh(struct usbip_device *ud)
97 {
98 if (ud->eh == current)
99 return; /* do not wait for myself */
100
101 kthread_stop(ud->eh);
102 usbip_dbg_eh("usbip_eh has finished\n");
103 }
104 EXPORT_SYMBOL_GPL(usbip_stop_eh);
105
usbip_event_add(struct usbip_device * ud,unsigned long event)106 void usbip_event_add(struct usbip_device *ud, unsigned long event)
107 {
108 spin_lock(&ud->lock);
109 ud->event |= event;
110 wake_up(&ud->eh_waitq);
111 spin_unlock(&ud->lock);
112 }
113 EXPORT_SYMBOL_GPL(usbip_event_add);
114
usbip_event_happened(struct usbip_device * ud)115 int usbip_event_happened(struct usbip_device *ud)
116 {
117 int happened = 0;
118
119 spin_lock(&ud->lock);
120 if (ud->event != 0)
121 happened = 1;
122 spin_unlock(&ud->lock);
123
124 return happened;
125 }
126 EXPORT_SYMBOL_GPL(usbip_event_happened);
127