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Commit 90e03207f468e84258270ad07095ef50f925c17d

Authored by Asias He
Committed by Rusty Russell
1 parent c877bab507
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

virtio: Use ida to allocate virtio index 

Current index allocation in virtio is based on a monotonically
increasing variable "index". This means we'll run out of numbers
after a while. E.g. someone crazy doing this in host side.

while(1) {
	hot-plug a virtio device
	hot-unplug the virito devcie
}

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Showing 1 changed file with 9 additions and 2 deletions Inline Diff

drivers/virtio/virtio.c
Diff comments   View file @ 90e0320
1 #include <linux/virtio.h> 1 #include <linux/virtio.h>
2 #include <linux/spinlock.h> 2 #include <linux/spinlock.h>
3 #include <linux/virtio_config.h> 3 #include <linux/virtio_config.h>
4 #include <linux/module.h> 4 #include <linux/module.h>
5 #include <linux/idr.h>
5 6
6 /* Unique numbering for virtio devices. */ 7 /* Unique numbering for virtio devices. */
7 static unsigned int dev_index; 8 static DEFINE_IDA(virtio_index_ida);
8 9
9 static ssize_t device_show(struct device *_d, 10 static ssize_t device_show(struct device *_d,
10 struct device_attribute *attr, char *buf) 11 struct device_attribute *attr, char *buf)
11 { 12 {
12 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 13 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
13 return sprintf(buf, "0x%04x\n", dev->id.device); 14 return sprintf(buf, "0x%04x\n", dev->id.device);
14 } 15 }
15 static ssize_t vendor_show(struct device *_d, 16 static ssize_t vendor_show(struct device *_d,
16 struct device_attribute *attr, char *buf) 17 struct device_attribute *attr, char *buf)
17 { 18 {
18 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 19 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
19 return sprintf(buf, "0x%04x\n", dev->id.vendor); 20 return sprintf(buf, "0x%04x\n", dev->id.vendor);
20 } 21 }
21 static ssize_t status_show(struct device *_d, 22 static ssize_t status_show(struct device *_d,
22 struct device_attribute *attr, char *buf) 23 struct device_attribute *attr, char *buf)
23 { 24 {
24 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 25 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
25 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); 26 return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
26 } 27 }
27 static ssize_t modalias_show(struct device *_d, 28 static ssize_t modalias_show(struct device *_d,
28 struct device_attribute *attr, char *buf) 29 struct device_attribute *attr, char *buf)
29 { 30 {
30 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 31 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
31 32
32 return sprintf(buf, "virtio:d%08Xv%08X\n", 33 return sprintf(buf, "virtio:d%08Xv%08X\n",
33 dev->id.device, dev->id.vendor); 34 dev->id.device, dev->id.vendor);
34 } 35 }
35 static ssize_t features_show(struct device *_d, 36 static ssize_t features_show(struct device *_d,
36 struct device_attribute *attr, char *buf) 37 struct device_attribute *attr, char *buf)
37 { 38 {
38 struct virtio_device *dev = container_of(_d, struct virtio_device, dev); 39 struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
39 unsigned int i; 40 unsigned int i;
40 ssize_t len = 0; 41 ssize_t len = 0;
41 42
42 /* We actually represent this as a bitstring, as it could be 43 /* We actually represent this as a bitstring, as it could be
43 * arbitrary length in future. */ 44 * arbitrary length in future. */
44 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++) 45 for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
45 len += sprintf(buf+len, "%c", 46 len += sprintf(buf+len, "%c",
46 test_bit(i, dev->features) ? '1' : '0'); 47 test_bit(i, dev->features) ? '1' : '0');
47 len += sprintf(buf+len, "\n"); 48 len += sprintf(buf+len, "\n");
48 return len; 49 return len;
49 } 50 }
50 static struct device_attribute virtio_dev_attrs[] = { 51 static struct device_attribute virtio_dev_attrs[] = {
51 __ATTR_RO(device), 52 __ATTR_RO(device),
52 __ATTR_RO(vendor), 53 __ATTR_RO(vendor),
53 __ATTR_RO(status), 54 __ATTR_RO(status),
54 __ATTR_RO(modalias), 55 __ATTR_RO(modalias),
55 __ATTR_RO(features), 56 __ATTR_RO(features),
56 __ATTR_NULL 57 __ATTR_NULL
57 }; 58 };
58 59
59 static inline int virtio_id_match(const struct virtio_device *dev, 60 static inline int virtio_id_match(const struct virtio_device *dev,
60 const struct virtio_device_id *id) 61 const struct virtio_device_id *id)
61 { 62 {
62 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID) 63 if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
63 return 0; 64 return 0;
64 65
65 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor; 66 return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
66 } 67 }
67 68
68 /* This looks through all the IDs a driver claims to support. If any of them 69 /* This looks through all the IDs a driver claims to support. If any of them
69 * match, we return 1 and the kernel will call virtio_dev_probe(). */ 70 * match, we return 1 and the kernel will call virtio_dev_probe(). */
70 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) 71 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
71 { 72 {
72 unsigned int i; 73 unsigned int i;
73 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 74 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
74 const struct virtio_device_id *ids; 75 const struct virtio_device_id *ids;
75 76
76 ids = container_of(_dr, struct virtio_driver, driver)->id_table; 77 ids = container_of(_dr, struct virtio_driver, driver)->id_table;
77 for (i = 0; ids[i].device; i++) 78 for (i = 0; ids[i].device; i++)
78 if (virtio_id_match(dev, &ids[i])) 79 if (virtio_id_match(dev, &ids[i]))
79 return 1; 80 return 1;
80 return 0; 81 return 0;
81 } 82 }
82 83
83 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) 84 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
84 { 85 {
85 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); 86 struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
86 87
87 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X", 88 return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
88 dev->id.device, dev->id.vendor); 89 dev->id.device, dev->id.vendor);
89 } 90 }
90 91
91 static void add_status(struct virtio_device *dev, unsigned status) 92 static void add_status(struct virtio_device *dev, unsigned status)
92 { 93 {
93 dev->config->set_status(dev, dev->config->get_status(dev) | status); 94 dev->config->set_status(dev, dev->config->get_status(dev) | status);
94 } 95 }
95 96
96 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 97 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
97 unsigned int fbit) 98 unsigned int fbit)
98 { 99 {
99 unsigned int i; 100 unsigned int i;
100 struct virtio_driver *drv = container_of(vdev->dev.driver, 101 struct virtio_driver *drv = container_of(vdev->dev.driver,
101 struct virtio_driver, driver); 102 struct virtio_driver, driver);
102 103
103 for (i = 0; i < drv->feature_table_size; i++) 104 for (i = 0; i < drv->feature_table_size; i++)
104 if (drv->feature_table[i] == fbit) 105 if (drv->feature_table[i] == fbit)
105 return; 106 return;
106 BUG(); 107 BUG();
107 } 108 }
108 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature); 109 EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
109 110
110 static int virtio_dev_probe(struct device *_d) 111 static int virtio_dev_probe(struct device *_d)
111 { 112 {
112 int err, i; 113 int err, i;
113 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 114 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
114 struct virtio_driver *drv = container_of(dev->dev.driver, 115 struct virtio_driver *drv = container_of(dev->dev.driver,
115 struct virtio_driver, driver); 116 struct virtio_driver, driver);
116 u32 device_features; 117 u32 device_features;
117 118
118 /* We have a driver! */ 119 /* We have a driver! */
119 add_status(dev, VIRTIO_CONFIG_S_DRIVER); 120 add_status(dev, VIRTIO_CONFIG_S_DRIVER);
120 121
121 /* Figure out what features the device supports. */ 122 /* Figure out what features the device supports. */
122 device_features = dev->config->get_features(dev); 123 device_features = dev->config->get_features(dev);
123 124
124 /* Features supported by both device and driver into dev->features. */ 125 /* Features supported by both device and driver into dev->features. */
125 memset(dev->features, 0, sizeof(dev->features)); 126 memset(dev->features, 0, sizeof(dev->features));
126 for (i = 0; i < drv->feature_table_size; i++) { 127 for (i = 0; i < drv->feature_table_size; i++) {
127 unsigned int f = drv->feature_table[i]; 128 unsigned int f = drv->feature_table[i];
128 BUG_ON(f >= 32); 129 BUG_ON(f >= 32);
129 if (device_features & (1 << f)) 130 if (device_features & (1 << f))
130 set_bit(f, dev->features); 131 set_bit(f, dev->features);
131 } 132 }
132 133
133 /* Transport features always preserved to pass to finalize_features. */ 134 /* Transport features always preserved to pass to finalize_features. */
134 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) 135 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
135 if (device_features & (1 << i)) 136 if (device_features & (1 << i))
136 set_bit(i, dev->features); 137 set_bit(i, dev->features);
137 138
138 dev->config->finalize_features(dev); 139 dev->config->finalize_features(dev);
139 140
140 err = drv->probe(dev); 141 err = drv->probe(dev);
141 if (err) 142 if (err)
142 add_status(dev, VIRTIO_CONFIG_S_FAILED); 143 add_status(dev, VIRTIO_CONFIG_S_FAILED);
143 else 144 else
144 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); 145 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
145 146
146 return err; 147 return err;
147 } 148 }
148 149
149 static int virtio_dev_remove(struct device *_d) 150 static int virtio_dev_remove(struct device *_d)
150 { 151 {
151 struct virtio_device *dev = container_of(_d,struct virtio_device,dev); 152 struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
152 struct virtio_driver *drv = container_of(dev->dev.driver, 153 struct virtio_driver *drv = container_of(dev->dev.driver,
153 struct virtio_driver, driver); 154 struct virtio_driver, driver);
154 155
155 drv->remove(dev); 156 drv->remove(dev);
156 157
157 /* Driver should have reset device. */ 158 /* Driver should have reset device. */
158 BUG_ON(dev->config->get_status(dev)); 159 BUG_ON(dev->config->get_status(dev));
159 160
160 /* Acknowledge the device's existence again. */ 161 /* Acknowledge the device's existence again. */
161 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 162 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
162 return 0; 163 return 0;
163 } 164 }
164 165
165 static struct bus_type virtio_bus = { 166 static struct bus_type virtio_bus = {
166 .name = "virtio", 167 .name = "virtio",
167 .match = virtio_dev_match, 168 .match = virtio_dev_match,
168 .dev_attrs = virtio_dev_attrs, 169 .dev_attrs = virtio_dev_attrs,
169 .uevent = virtio_uevent, 170 .uevent = virtio_uevent,
170 .probe = virtio_dev_probe, 171 .probe = virtio_dev_probe,
171 .remove = virtio_dev_remove, 172 .remove = virtio_dev_remove,
172 }; 173 };
173 174
174 int register_virtio_driver(struct virtio_driver *driver) 175 int register_virtio_driver(struct virtio_driver *driver)
175 { 176 {
176 /* Catch this early. */ 177 /* Catch this early. */
177 BUG_ON(driver->feature_table_size && !driver->feature_table); 178 BUG_ON(driver->feature_table_size && !driver->feature_table);
178 driver->driver.bus = &virtio_bus; 179 driver->driver.bus = &virtio_bus;
179 return driver_register(&driver->driver); 180 return driver_register(&driver->driver);
180 } 181 }
181 EXPORT_SYMBOL_GPL(register_virtio_driver); 182 EXPORT_SYMBOL_GPL(register_virtio_driver);
182 183
183 void unregister_virtio_driver(struct virtio_driver *driver) 184 void unregister_virtio_driver(struct virtio_driver *driver)
184 { 185 {
185 driver_unregister(&driver->driver); 186 driver_unregister(&driver->driver);
186 } 187 }
187 EXPORT_SYMBOL_GPL(unregister_virtio_driver); 188 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
188 189
189 int register_virtio_device(struct virtio_device *dev) 190 int register_virtio_device(struct virtio_device *dev)
190 { 191 {
191 int err; 192 int err;
192 193
193 dev->dev.bus = &virtio_bus; 194 dev->dev.bus = &virtio_bus;
194 195
195 /* Assign a unique device index and hence name. */ 196 /* Assign a unique device index and hence name. */
196 dev->index = dev_index++; 197 err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
198 if (err < 0)
199 goto out;
200
201 dev->index = err;
197 dev_set_name(&dev->dev, "virtio%u", dev->index); 202 dev_set_name(&dev->dev, "virtio%u", dev->index);
198 203
199 /* We always start by resetting the device, in case a previous 204 /* We always start by resetting the device, in case a previous
200 * driver messed it up. This also tests that code path a little. */ 205 * driver messed it up. This also tests that code path a little. */
201 dev->config->reset(dev); 206 dev->config->reset(dev);
202 207
203 /* Acknowledge that we've seen the device. */ 208 /* Acknowledge that we've seen the device. */
204 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); 209 add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
205 210
206 INIT_LIST_HEAD(&dev->vqs); 211 INIT_LIST_HEAD(&dev->vqs);
207 212
208 /* device_register() causes the bus infrastructure to look for a 213 /* device_register() causes the bus infrastructure to look for a
209 * matching driver. */ 214 * matching driver. */
210 err = device_register(&dev->dev); 215 err = device_register(&dev->dev);
216 out:
211 if (err) 217 if (err)
212 add_status(dev, VIRTIO_CONFIG_S_FAILED); 218 add_status(dev, VIRTIO_CONFIG_S_FAILED);
213 return err; 219 return err;
214 } 220 }
215 EXPORT_SYMBOL_GPL(register_virtio_device); 221 EXPORT_SYMBOL_GPL(register_virtio_device);
216 222
217 void unregister_virtio_device(struct virtio_device *dev) 223 void unregister_virtio_device(struct virtio_device *dev)
218 { 224 {
219 device_unregister(&dev->dev); 225 device_unregister(&dev->dev);
226 ida_simple_remove(&virtio_index_ida, dev->index);
220 } 227 }
221 EXPORT_SYMBOL_GPL(unregister_virtio_device); 228 EXPORT_SYMBOL_GPL(unregister_virtio_device);
222 229
223 static int virtio_init(void) 230 static int virtio_init(void)
224 { 231 {
225 if (bus_register(&virtio_bus) != 0) 232 if (bus_register(&virtio_bus) != 0)
226 panic("virtio bus registration failed"); 233 panic("virtio bus registration failed");
227 return 0; 234 return 0;
228 } 235 }
229 236
230 static void __exit virtio_exit(void) 237 static void __exit virtio_exit(void)
231 { 238 {
232 bus_unregister(&virtio_bus); 239 bus_unregister(&virtio_bus);
233 } 240 }
234 core_initcall(virtio_init); 241 core_initcall(virtio_init);
235 module_exit(virtio_exit); 242 module_exit(virtio_exit);
236 243
237 MODULE_LICENSE("GPL"); 244 MODULE_LICENSE("GPL");
238 245