[PATCH] drivers/message/i2o/pci.c: fix a NULL pointer dereference
[linux-2.6] / drivers / message / i2o / driver.c
1 /*
2  *      Functions to handle I2O drivers (OSMs) and I2O bus type for sysfs
3  *
4  *      Copyright (C) 2004      Markus Lidel <Markus.Lidel@shadowconnect.com>
5  *
6  *      This program is free software; you can redistribute it and/or modify it
7  *      under the terms of the GNU General Public License as published by the
8  *      Free Software Foundation; either version 2 of the License, or (at your
9  *      option) any later version.
10  *
11  *      Fixes/additions:
12  *              Markus Lidel <Markus.Lidel@shadowconnect.com>
13  *                      initial version.
14  */
15
16 #include <linux/device.h>
17 #include <linux/module.h>
18 #include <linux/rwsem.h>
19 #include <linux/i2o.h>
20 #include <linux/workqueue.h>
21 #include <linux/string.h>
22 #include <linux/slab.h>
23 #include "core.h"
24
25 #define OSM_NAME        "i2o"
26
27 /* max_drivers - Maximum I2O drivers (OSMs) which could be registered */
28 static unsigned int i2o_max_drivers = I2O_MAX_DRIVERS;
29 module_param_named(max_drivers, i2o_max_drivers, uint, 0);
30 MODULE_PARM_DESC(max_drivers, "maximum number of OSM's to support");
31
32 /* I2O drivers lock and array */
33 static spinlock_t i2o_drivers_lock;
34 static struct i2o_driver **i2o_drivers;
35
36 /**
37  *      i2o_bus_match - Tell if a I2O device class id match the class ids of
38  *                      the I2O driver (OSM)
39  *
40  *      @dev: device which should be verified
41  *      @drv: the driver to match against
42  *
43  *      Used by the bus to check if the driver wants to handle the device.
44  *
45  *      Returns 1 if the class ids of the driver match the class id of the
46  *      device, otherwise 0.
47  */
48 static int i2o_bus_match(struct device *dev, struct device_driver *drv)
49 {
50         struct i2o_device *i2o_dev = to_i2o_device(dev);
51         struct i2o_driver *i2o_drv = to_i2o_driver(drv);
52         struct i2o_class_id *ids = i2o_drv->classes;
53
54         if (ids)
55                 while (ids->class_id != I2O_CLASS_END) {
56                         if (ids->class_id == i2o_dev->lct_data.class_id)
57                                 return 1;
58                         ids++;
59                 }
60         return 0;
61 };
62
63 /* I2O bus type */
64 extern struct device_attribute i2o_device_attrs[];
65
66 struct bus_type i2o_bus_type = {
67         .name = "i2o",
68         .match = i2o_bus_match,
69         .dev_attrs = i2o_device_attrs,
70 };
71
72 /**
73  *      i2o_driver_register - Register a I2O driver (OSM) in the I2O core
74  *      @drv: I2O driver which should be registered
75  *
76  *      Registers the OSM drv in the I2O core and creates an event queues if
77  *      necessary.
78  *
79  *      Returns 0 on success or negative error code on failure.
80  */
81 int i2o_driver_register(struct i2o_driver *drv)
82 {
83         struct i2o_controller *c;
84         int i;
85         int rc = 0;
86         unsigned long flags;
87
88         osm_debug("Register driver %s\n", drv->name);
89
90         if (drv->event) {
91                 drv->event_queue = create_workqueue(drv->name);
92                 if (!drv->event_queue) {
93                         osm_err("Could not initialize event queue for driver "
94                                 "%s\n", drv->name);
95                         return -EFAULT;
96                 }
97                 osm_debug("Event queue initialized for driver %s\n", drv->name);
98         } else
99                 drv->event_queue = NULL;
100
101         drv->driver.name = drv->name;
102         drv->driver.bus = &i2o_bus_type;
103
104         spin_lock_irqsave(&i2o_drivers_lock, flags);
105
106         for (i = 0; i2o_drivers[i]; i++)
107                 if (i >= i2o_max_drivers) {
108                         osm_err("too many drivers registered, increase "
109                                 "max_drivers\n");
110                         spin_unlock_irqrestore(&i2o_drivers_lock, flags);
111                         return -EFAULT;
112                 }
113
114         drv->context = i;
115         i2o_drivers[i] = drv;
116
117         spin_unlock_irqrestore(&i2o_drivers_lock, flags);
118
119         osm_debug("driver %s gets context id %d\n", drv->name, drv->context);
120
121         list_for_each_entry(c, &i2o_controllers, list) {
122                 struct i2o_device *i2o_dev;
123
124                 i2o_driver_notify_controller_add(drv, c);
125                 list_for_each_entry(i2o_dev, &c->devices, list)
126                     i2o_driver_notify_device_add(drv, i2o_dev);
127         }
128
129         rc = driver_register(&drv->driver);
130         if (rc)
131                 destroy_workqueue(drv->event_queue);
132
133         return rc;
134 };
135
136 /**
137  *      i2o_driver_unregister - Unregister a I2O driver (OSM) from the I2O core
138  *      @drv: I2O driver which should be unregistered
139  *
140  *      Unregisters the OSM drv from the I2O core and cleanup event queues if
141  *      necessary.
142  */
143 void i2o_driver_unregister(struct i2o_driver *drv)
144 {
145         struct i2o_controller *c;
146         unsigned long flags;
147
148         osm_debug("unregister driver %s\n", drv->name);
149
150         driver_unregister(&drv->driver);
151
152         list_for_each_entry(c, &i2o_controllers, list) {
153                 struct i2o_device *i2o_dev;
154
155                 list_for_each_entry(i2o_dev, &c->devices, list)
156                     i2o_driver_notify_device_remove(drv, i2o_dev);
157
158                 i2o_driver_notify_controller_remove(drv, c);
159         }
160
161         spin_lock_irqsave(&i2o_drivers_lock, flags);
162         i2o_drivers[drv->context] = NULL;
163         spin_unlock_irqrestore(&i2o_drivers_lock, flags);
164
165         if (drv->event_queue) {
166                 destroy_workqueue(drv->event_queue);
167                 drv->event_queue = NULL;
168                 osm_debug("event queue removed for %s\n", drv->name);
169         }
170 };
171
172 /**
173  *      i2o_driver_dispatch - dispatch an I2O reply message
174  *      @c: I2O controller of the message
175  *      @m: I2O message number
176  *      @msg: I2O message to be delivered
177  *
178  *      The reply is delivered to the driver from which the original message
179  *      was. This function is only called from interrupt context.
180  *
181  *      Returns 0 on success and the message should not be flushed. Returns > 0
182  *      on success and if the message should be flushed afterwords. Returns
183  *      negative error code on failure (the message will be flushed too).
184  */
185 int i2o_driver_dispatch(struct i2o_controller *c, u32 m)
186 {
187         struct i2o_driver *drv;
188         struct i2o_message *msg = i2o_msg_out_to_virt(c, m);
189         u32 context = le32_to_cpu(msg->u.s.icntxt);
190         unsigned long flags;
191
192         if (unlikely(context >= i2o_max_drivers)) {
193                 osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
194                          context);
195                 return -EIO;
196         }
197
198         spin_lock_irqsave(&i2o_drivers_lock, flags);
199         drv = i2o_drivers[context];
200         spin_unlock_irqrestore(&i2o_drivers_lock, flags);
201
202         if (unlikely(!drv)) {
203                 osm_warn("%s: Spurious reply to unknown driver %d\n", c->name,
204                          context);
205                 return -EIO;
206         }
207
208         if ((le32_to_cpu(msg->u.head[1]) >> 24) == I2O_CMD_UTIL_EVT_REGISTER) {
209                 struct i2o_device *dev, *tmp;
210                 struct i2o_event *evt;
211                 u16 size;
212                 u16 tid = le32_to_cpu(msg->u.head[1]) & 0xfff;
213
214                 osm_debug("event received from device %d\n", tid);
215
216                 if (!drv->event)
217                         return -EIO;
218
219                 /* cut of header from message size (in 32-bit words) */
220                 size = (le32_to_cpu(msg->u.head[0]) >> 16) - 5;
221
222                 evt = kmalloc(size * 4 + sizeof(*evt), GFP_ATOMIC | __GFP_ZERO);
223                 if (!evt)
224                         return -ENOMEM;
225
226                 evt->size = size;
227                 evt->tcntxt = le32_to_cpu(msg->u.s.tcntxt);
228                 evt->event_indicator = le32_to_cpu(msg->body[0]);
229                 memcpy(&evt->tcntxt, &msg->u.s.tcntxt, size * 4);
230
231                 list_for_each_entry_safe(dev, tmp, &c->devices, list)
232                     if (dev->lct_data.tid == tid) {
233                         evt->i2o_dev = dev;
234                         break;
235                 }
236
237                 INIT_WORK(&evt->work, (void (*)(void *))drv->event, evt);
238                 queue_work(drv->event_queue, &evt->work);
239                 return 1;
240         }
241
242         if (unlikely(!drv->reply)) {
243                 osm_debug("%s: Reply to driver %s, but no reply function"
244                           " defined!\n", c->name, drv->name);
245                 return -EIO;
246         }
247
248         return drv->reply(c, m, msg);
249 }
250
251 /**
252  *      i2o_driver_notify_controller_add_all - Send notify of added controller
253  *                                             to all I2O drivers
254  *
255  *      Send notifications to all registered drivers that a new controller was
256  *      added.
257  */
258 void i2o_driver_notify_controller_add_all(struct i2o_controller *c)
259 {
260         int i;
261         struct i2o_driver *drv;
262
263         for (i = 0; i < I2O_MAX_DRIVERS; i++) {
264                 drv = i2o_drivers[i];
265
266                 if (drv)
267                         i2o_driver_notify_controller_add(drv, c);
268         }
269 }
270
271 /**
272  *      i2o_driver_notify_controller_remove_all - Send notify of removed
273  *                                                controller to all I2O drivers
274  *
275  *      Send notifications to all registered drivers that a controller was
276  *      removed.
277  */
278 void i2o_driver_notify_controller_remove_all(struct i2o_controller *c)
279 {
280         int i;
281         struct i2o_driver *drv;
282
283         for (i = 0; i < I2O_MAX_DRIVERS; i++) {
284                 drv = i2o_drivers[i];
285
286                 if (drv)
287                         i2o_driver_notify_controller_remove(drv, c);
288         }
289 }
290
291 /**
292  *      i2o_driver_notify_device_add_all - Send notify of added device to all
293  *                                         I2O drivers
294  *
295  *      Send notifications to all registered drivers that a device was added.
296  */
297 void i2o_driver_notify_device_add_all(struct i2o_device *i2o_dev)
298 {
299         int i;
300         struct i2o_driver *drv;
301
302         for (i = 0; i < I2O_MAX_DRIVERS; i++) {
303                 drv = i2o_drivers[i];
304
305                 if (drv)
306                         i2o_driver_notify_device_add(drv, i2o_dev);
307         }
308 }
309
310 /**
311  *      i2o_driver_notify_device_remove_all - Send notify of removed device to
312  *                                            all I2O drivers
313  *
314  *      Send notifications to all registered drivers that a device was removed.
315  */
316 void i2o_driver_notify_device_remove_all(struct i2o_device *i2o_dev)
317 {
318         int i;
319         struct i2o_driver *drv;
320
321         for (i = 0; i < I2O_MAX_DRIVERS; i++) {
322                 drv = i2o_drivers[i];
323
324                 if (drv)
325                         i2o_driver_notify_device_remove(drv, i2o_dev);
326         }
327 }
328
329 /**
330  *      i2o_driver_init - initialize I2O drivers (OSMs)
331  *
332  *      Registers the I2O bus and allocate memory for the array of OSMs.
333  *
334  *      Returns 0 on success or negative error code on failure.
335  */
336 int __init i2o_driver_init(void)
337 {
338         int rc = 0;
339
340         spin_lock_init(&i2o_drivers_lock);
341
342         if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64) ||
343             ((i2o_max_drivers ^ (i2o_max_drivers - 1)) !=
344              (2 * i2o_max_drivers - 1))) {
345                 osm_warn("max_drivers set to %d, but must be >=2 and <= 64 and "
346                          "a power of 2\n", i2o_max_drivers);
347                 i2o_max_drivers = I2O_MAX_DRIVERS;
348         }
349         osm_info("max drivers = %d\n", i2o_max_drivers);
350
351         i2o_drivers =
352             kmalloc(i2o_max_drivers * sizeof(*i2o_drivers), GFP_KERNEL);
353         if (!i2o_drivers)
354                 return -ENOMEM;
355
356         memset(i2o_drivers, 0, i2o_max_drivers * sizeof(*i2o_drivers));
357
358         rc = bus_register(&i2o_bus_type);
359
360         if (rc < 0)
361                 kfree(i2o_drivers);
362
363         return rc;
364 };
365
366 /**
367  *      i2o_driver_exit - clean up I2O drivers (OSMs)
368  *
369  *      Unregisters the I2O bus and free driver array.
370  */
371 void __exit i2o_driver_exit(void)
372 {
373         bus_unregister(&i2o_bus_type);
374         kfree(i2o_drivers);
375 };
376
377 EXPORT_SYMBOL(i2o_driver_register);
378 EXPORT_SYMBOL(i2o_driver_unregister);
379 EXPORT_SYMBOL(i2o_driver_notify_controller_add_all);
380 EXPORT_SYMBOL(i2o_driver_notify_controller_remove_all);
381 EXPORT_SYMBOL(i2o_driver_notify_device_add_all);
382 EXPORT_SYMBOL(i2o_driver_notify_device_remove_all);