ia64/linux-2.6.18-xen.hg

view drivers/connector/connector.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /*
2 * connector.c
3 *
4 * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5 * All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/list.h>
25 #include <linux/skbuff.h>
26 #include <linux/netlink.h>
27 #include <linux/moduleparam.h>
28 #include <linux/connector.h>
29 #include <linux/mutex.h>
31 #include <net/sock.h>
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
35 MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
37 static u32 cn_idx = CN_IDX_CONNECTOR;
38 static u32 cn_val = CN_VAL_CONNECTOR;
40 module_param(cn_idx, uint, 0);
41 module_param(cn_val, uint, 0);
42 MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
43 MODULE_PARM_DESC(cn_val, "Connector's main device val.");
45 static DEFINE_MUTEX(notify_lock);
46 static LIST_HEAD(notify_list);
48 static struct cn_dev cdev;
50 int cn_already_initialized = 0;
52 /*
53 * msg->seq and msg->ack are used to determine message genealogy.
54 * When someone sends message it puts there locally unique sequence
55 * and random acknowledge numbers. Sequence number may be copied into
56 * nlmsghdr->nlmsg_seq too.
57 *
58 * Sequence number is incremented with each message to be sent.
59 *
60 * If we expect reply to our message then the sequence number in
61 * received message MUST be the same as in original message, and
62 * acknowledge number MUST be the same + 1.
63 *
64 * If we receive a message and its sequence number is not equal to the
65 * one we are expecting then it is a new message.
66 *
67 * If we receive a message and its sequence number is the same as one
68 * we are expecting but it's acknowledgement number is not equal to
69 * the acknowledgement number in the original message + 1, then it is
70 * a new message.
71 *
72 */
73 int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
74 {
75 struct cn_callback_entry *__cbq;
76 unsigned int size;
77 struct sk_buff *skb;
78 struct nlmsghdr *nlh;
79 struct cn_msg *data;
80 struct cn_dev *dev = &cdev;
81 u32 group = 0;
82 int found = 0;
84 if (!__group) {
85 spin_lock_bh(&dev->cbdev->queue_lock);
86 list_for_each_entry(__cbq, &dev->cbdev->queue_list,
87 callback_entry) {
88 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
89 found = 1;
90 group = __cbq->group;
91 }
92 }
93 spin_unlock_bh(&dev->cbdev->queue_lock);
95 if (!found)
96 return -ENODEV;
97 } else {
98 group = __group;
99 }
101 if (!netlink_has_listeners(dev->nls, group))
102 return -ESRCH;
104 size = NLMSG_SPACE(sizeof(*msg) + msg->len);
106 skb = alloc_skb(size, gfp_mask);
107 if (!skb)
108 return -ENOMEM;
110 nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
112 data = NLMSG_DATA(nlh);
114 memcpy(data, msg, sizeof(*data) + msg->len);
116 NETLINK_CB(skb).dst_group = group;
118 return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
120 nlmsg_failure:
121 kfree_skb(skb);
122 return -EINVAL;
123 }
124 EXPORT_SYMBOL_GPL(cn_netlink_send);
126 /*
127 * Callback helper - queues work and setup destructor for given data.
128 */
129 static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
130 {
131 struct cn_callback_entry *__cbq;
132 struct cn_dev *dev = &cdev;
133 int err = -ENODEV;
135 spin_lock_bh(&dev->cbdev->queue_lock);
136 list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
137 if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
138 if (likely(!test_bit(0, &__cbq->work.pending) &&
139 __cbq->data.ddata == NULL)) {
140 __cbq->data.callback_priv = msg;
142 __cbq->data.ddata = data;
143 __cbq->data.destruct_data = destruct_data;
145 if (queue_work(dev->cbdev->cn_queue,
146 &__cbq->work))
147 err = 0;
148 } else {
149 struct work_struct *w;
150 struct cn_callback_data *d;
152 w = kzalloc(sizeof(*w) + sizeof(*d), GFP_ATOMIC);
153 if (w) {
154 d = (struct cn_callback_data *)(w+1);
156 d->callback_priv = msg;
157 d->callback = __cbq->data.callback;
158 d->ddata = data;
159 d->destruct_data = destruct_data;
160 d->free = w;
162 INIT_LIST_HEAD(&w->entry);
163 w->pending = 0;
164 w->func = &cn_queue_wrapper;
165 w->data = d;
166 init_timer(&w->timer);
168 if (queue_work(dev->cbdev->cn_queue, w))
169 err = 0;
170 else {
171 kfree(w);
172 err = -EINVAL;
173 }
174 } else
175 err = -ENOMEM;
176 }
177 break;
178 }
179 }
180 spin_unlock_bh(&dev->cbdev->queue_lock);
182 return err;
183 }
185 /*
186 * Skb receive helper - checks skb and msg size and calls callback
187 * helper.
188 */
189 static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
190 {
191 u32 pid, uid, seq, group;
192 struct cn_msg *msg;
194 pid = NETLINK_CREDS(skb)->pid;
195 uid = NETLINK_CREDS(skb)->uid;
196 seq = nlh->nlmsg_seq;
197 group = NETLINK_CB((skb)).dst_group;
198 msg = NLMSG_DATA(nlh);
200 return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
201 }
203 /*
204 * Main netlink receiving function.
205 *
206 * It checks skb and netlink header sizes and calls the skb receive
207 * helper with a shared skb.
208 */
209 static void cn_rx_skb(struct sk_buff *__skb)
210 {
211 struct nlmsghdr *nlh;
212 u32 len;
213 int err;
214 struct sk_buff *skb;
216 skb = skb_get(__skb);
218 if (skb->len >= NLMSG_SPACE(0)) {
219 nlh = (struct nlmsghdr *)skb->data;
221 if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
222 skb->len < nlh->nlmsg_len ||
223 nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
224 kfree_skb(skb);
225 goto out;
226 }
228 len = NLMSG_ALIGN(nlh->nlmsg_len);
229 if (len > skb->len)
230 len = skb->len;
232 err = __cn_rx_skb(skb, nlh);
233 if (err < 0)
234 kfree_skb(skb);
235 }
237 out:
238 kfree_skb(__skb);
239 }
241 /*
242 * Netlink socket input callback - dequeues the skbs and calls the
243 * main netlink receiving function.
244 */
245 static void cn_input(struct sock *sk, int len)
246 {
247 struct sk_buff *skb;
249 while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
250 cn_rx_skb(skb);
251 }
253 /*
254 * Notification routing.
255 *
256 * Gets id and checks if there are notification request for it's idx
257 * and val. If there are such requests notify the listeners with the
258 * given notify event.
259 *
260 */
261 static void cn_notify(struct cb_id *id, u32 notify_event)
262 {
263 struct cn_ctl_entry *ent;
265 mutex_lock(&notify_lock);
266 list_for_each_entry(ent, &notify_list, notify_entry) {
267 int i;
268 struct cn_notify_req *req;
269 struct cn_ctl_msg *ctl = ent->msg;
270 int idx_found, val_found;
272 idx_found = val_found = 0;
274 req = (struct cn_notify_req *)ctl->data;
275 for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
276 if (id->idx >= req->first &&
277 id->idx < req->first + req->range) {
278 idx_found = 1;
279 break;
280 }
281 }
283 for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
284 if (id->val >= req->first &&
285 id->val < req->first + req->range) {
286 val_found = 1;
287 break;
288 }
289 }
291 if (idx_found && val_found) {
292 struct cn_msg m = { .ack = notify_event, };
294 memcpy(&m.id, id, sizeof(m.id));
295 cn_netlink_send(&m, ctl->group, GFP_KERNEL);
296 }
297 }
298 mutex_unlock(&notify_lock);
299 }
301 /*
302 * Callback add routing - adds callback with given ID and name.
303 * If there is registered callback with the same ID it will not be added.
304 *
305 * May sleep.
306 */
307 int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
308 {
309 int err;
310 struct cn_dev *dev = &cdev;
312 if (!cn_already_initialized)
313 return -EAGAIN;
315 err = cn_queue_add_callback(dev->cbdev, name, id, callback);
316 if (err)
317 return err;
319 cn_notify(id, 0);
321 return 0;
322 }
323 EXPORT_SYMBOL_GPL(cn_add_callback);
325 /*
326 * Callback remove routing - removes callback
327 * with given ID.
328 * If there is no registered callback with given
329 * ID nothing happens.
330 *
331 * May sleep while waiting for reference counter to become zero.
332 */
333 void cn_del_callback(struct cb_id *id)
334 {
335 struct cn_dev *dev = &cdev;
337 cn_queue_del_callback(dev->cbdev, id);
338 cn_notify(id, 1);
339 }
340 EXPORT_SYMBOL_GPL(cn_del_callback);
342 /*
343 * Checks two connector's control messages to be the same.
344 * Returns 1 if they are the same or if the first one is corrupted.
345 */
346 static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
347 {
348 int i;
349 struct cn_notify_req *req1, *req2;
351 if (m1->idx_notify_num != m2->idx_notify_num)
352 return 0;
354 if (m1->val_notify_num != m2->val_notify_num)
355 return 0;
357 if (m1->len != m2->len)
358 return 0;
360 if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
361 m1->len)
362 return 1;
364 req1 = (struct cn_notify_req *)m1->data;
365 req2 = (struct cn_notify_req *)m2->data;
367 for (i = 0; i < m1->idx_notify_num; ++i) {
368 if (req1->first != req2->first || req1->range != req2->range)
369 return 0;
370 req1++;
371 req2++;
372 }
374 for (i = 0; i < m1->val_notify_num; ++i) {
375 if (req1->first != req2->first || req1->range != req2->range)
376 return 0;
377 req1++;
378 req2++;
379 }
381 return 1;
382 }
384 /*
385 * Main connector device's callback.
386 *
387 * Used for notification of a request's processing.
388 */
389 static void cn_callback(void *data)
390 {
391 struct cn_msg *msg = data;
392 struct cn_ctl_msg *ctl;
393 struct cn_ctl_entry *ent;
394 u32 size;
396 if (msg->len < sizeof(*ctl))
397 return;
399 ctl = (struct cn_ctl_msg *)msg->data;
401 size = (sizeof(*ctl) + ((ctl->idx_notify_num +
402 ctl->val_notify_num) *
403 sizeof(struct cn_notify_req)));
405 if (msg->len != size)
406 return;
408 if (ctl->len + sizeof(*ctl) != msg->len)
409 return;
411 /*
412 * Remove notification.
413 */
414 if (ctl->group == 0) {
415 struct cn_ctl_entry *n;
417 mutex_lock(&notify_lock);
418 list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
419 if (cn_ctl_msg_equals(ent->msg, ctl)) {
420 list_del(&ent->notify_entry);
421 kfree(ent);
422 }
423 }
424 mutex_unlock(&notify_lock);
426 return;
427 }
429 size += sizeof(*ent);
431 ent = kzalloc(size, GFP_KERNEL);
432 if (!ent)
433 return;
435 ent->msg = (struct cn_ctl_msg *)(ent + 1);
437 memcpy(ent->msg, ctl, size - sizeof(*ent));
439 mutex_lock(&notify_lock);
440 list_add(&ent->notify_entry, &notify_list);
441 mutex_unlock(&notify_lock);
442 }
444 static int __devinit cn_init(void)
445 {
446 struct cn_dev *dev = &cdev;
447 int err;
449 dev->input = cn_input;
450 dev->id.idx = cn_idx;
451 dev->id.val = cn_val;
453 dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
454 CN_NETLINK_USERS + 0xf,
455 dev->input, THIS_MODULE);
456 if (!dev->nls)
457 return -EIO;
459 dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
460 if (!dev->cbdev) {
461 if (dev->nls->sk_socket)
462 sock_release(dev->nls->sk_socket);
463 return -EINVAL;
464 }
466 cn_already_initialized = 1;
468 err = cn_add_callback(&dev->id, "connector", &cn_callback);
469 if (err) {
470 cn_already_initialized = 0;
471 cn_queue_free_dev(dev->cbdev);
472 if (dev->nls->sk_socket)
473 sock_release(dev->nls->sk_socket);
474 return -EINVAL;
475 }
477 return 0;
478 }
480 static void __devexit cn_fini(void)
481 {
482 struct cn_dev *dev = &cdev;
484 cn_already_initialized = 0;
486 cn_del_callback(&dev->id);
487 cn_queue_free_dev(dev->cbdev);
488 if (dev->nls->sk_socket)
489 sock_release(dev->nls->sk_socket);
490 }
492 subsys_initcall(cn_init);
493 module_exit(cn_fini);