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-rw-r--r--drivers/xen/pvcalls-back.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 9044cf21b31c..72d2fce27a34 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -25,20 +25,175 @@
25#include <xen/xenbus.h> 25#include <xen/xenbus.h>
26#include <xen/interface/io/pvcalls.h> 26#include <xen/interface/io/pvcalls.h>
27 27
28#define PVCALLS_VERSIONS "1"
29#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
30
28struct pvcalls_back_global { 31struct pvcalls_back_global {
29 struct list_head frontends; 32 struct list_head frontends;
30 struct semaphore frontends_lock; 33 struct semaphore frontends_lock;
31} pvcalls_back_global; 34} pvcalls_back_global;
32 35
36static int backend_connect(struct xenbus_device *dev)
37{
38 return 0;
39}
40
41static int backend_disconnect(struct xenbus_device *dev)
42{
43 return 0;
44}
45
33static int pvcalls_back_probe(struct xenbus_device *dev, 46static int pvcalls_back_probe(struct xenbus_device *dev,
34 const struct xenbus_device_id *id) 47 const struct xenbus_device_id *id)
35{ 48{
49 int err, abort;
50 struct xenbus_transaction xbt;
51
52again:
53 abort = 1;
54
55 err = xenbus_transaction_start(&xbt);
56 if (err) {
57 pr_warn("%s cannot create xenstore transaction\n", __func__);
58 return err;
59 }
60
61 err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
62 PVCALLS_VERSIONS);
63 if (err) {
64 pr_warn("%s write out 'versions' failed\n", __func__);
65 goto abort;
66 }
67
68 err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
69 MAX_RING_ORDER);
70 if (err) {
71 pr_warn("%s write out 'max-page-order' failed\n", __func__);
72 goto abort;
73 }
74
75 err = xenbus_printf(xbt, dev->nodename, "function-calls",
76 XENBUS_FUNCTIONS_CALLS);
77 if (err) {
78 pr_warn("%s write out 'function-calls' failed\n", __func__);
79 goto abort;
80 }
81
82 abort = 0;
83abort:
84 err = xenbus_transaction_end(xbt, abort);
85 if (err) {
86 if (err == -EAGAIN && !abort)
87 goto again;
88 pr_warn("%s cannot complete xenstore transaction\n", __func__);
89 return err;
90 }
91
92 if (abort)
93 return -EFAULT;
94
95 xenbus_switch_state(dev, XenbusStateInitWait);
96
36 return 0; 97 return 0;
37} 98}
38 99
100static void set_backend_state(struct xenbus_device *dev,
101 enum xenbus_state state)
102{
103 while (dev->state != state) {
104 switch (dev->state) {
105 case XenbusStateClosed:
106 switch (state) {
107 case XenbusStateInitWait:
108 case XenbusStateConnected:
109 xenbus_switch_state(dev, XenbusStateInitWait);
110 break;
111 case XenbusStateClosing:
112 xenbus_switch_state(dev, XenbusStateClosing);
113 break;
114 default:
115 __WARN();
116 }
117 break;
118 case XenbusStateInitWait:
119 case XenbusStateInitialised:
120 switch (state) {
121 case XenbusStateConnected:
122 backend_connect(dev);
123 xenbus_switch_state(dev, XenbusStateConnected);
124 break;
125 case XenbusStateClosing:
126 case XenbusStateClosed:
127 xenbus_switch_state(dev, XenbusStateClosing);
128 break;
129 default:
130 __WARN();
131 }
132 break;
133 case XenbusStateConnected:
134 switch (state) {
135 case XenbusStateInitWait:
136 case XenbusStateClosing:
137 case XenbusStateClosed:
138 down(&pvcalls_back_global.frontends_lock);
139 backend_disconnect(dev);
140 up(&pvcalls_back_global.frontends_lock);
141 xenbus_switch_state(dev, XenbusStateClosing);
142 break;
143 default:
144 __WARN();
145 }
146 break;
147 case XenbusStateClosing:
148 switch (state) {
149 case XenbusStateInitWait:
150 case XenbusStateConnected:
151 case XenbusStateClosed:
152 xenbus_switch_state(dev, XenbusStateClosed);
153 break;
154 default:
155 __WARN();
156 }
157 break;
158 default:
159 __WARN();
160 }
161 }
162}
163
39static void pvcalls_back_changed(struct xenbus_device *dev, 164static void pvcalls_back_changed(struct xenbus_device *dev,
40 enum xenbus_state frontend_state) 165 enum xenbus_state frontend_state)
41{ 166{
167 switch (frontend_state) {
168 case XenbusStateInitialising:
169 set_backend_state(dev, XenbusStateInitWait);
170 break;
171
172 case XenbusStateInitialised:
173 case XenbusStateConnected:
174 set_backend_state(dev, XenbusStateConnected);
175 break;
176
177 case XenbusStateClosing:
178 set_backend_state(dev, XenbusStateClosing);
179 break;
180
181 case XenbusStateClosed:
182 set_backend_state(dev, XenbusStateClosed);
183 if (xenbus_dev_is_online(dev))
184 break;
185 device_unregister(&dev->dev);
186 break;
187 case XenbusStateUnknown:
188 set_backend_state(dev, XenbusStateClosed);
189 device_unregister(&dev->dev);
190 break;
191
192 default:
193 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
194 frontend_state);
195 break;
196 }
42} 197}
43 198
44static int pvcalls_back_remove(struct xenbus_device *dev) 199static int pvcalls_back_remove(struct xenbus_device *dev)
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-24 12:48:31 -0400