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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CAIF Interface registration.
4 * Copyright (C) ST-Ericsson AB 2010
5 * Author: Sjur Brendeland
6 *
7 * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
8 * and Sakari Ailus <sakari.ailus@nokia.com>
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
12
13#include <linux/kernel.h>
14#include <linux/if_arp.h>
15#include <linux/net.h>
16#include <linux/netdevice.h>
17#include <linux/mutex.h>
18#include <linux/module.h>
19#include <linux/spinlock.h>
20#include <net/netns/generic.h>
21#include <net/net_namespace.h>
22#include <net/pkt_sched.h>
23#include <net/caif/caif_device.h>
24#include <net/caif/caif_layer.h>
25#include <net/caif/caif_dev.h>
26#include <net/caif/cfpkt.h>
27#include <net/caif/cfcnfg.h>
28#include <net/caif/cfserl.h>
29
30MODULE_LICENSE("GPL");
31
32/* Used for local tracking of the CAIF net devices */
33struct caif_device_entry {
34 struct cflayer layer;
35 struct list_head list;
36 struct net_device *netdev;
37 int __percpu *pcpu_refcnt;
38 spinlock_t flow_lock;
39 struct sk_buff *xoff_skb;
40 void (*xoff_skb_dtor)(struct sk_buff *skb);
41 bool xoff;
42};
43
44struct caif_device_entry_list {
45 struct list_head list;
46 /* Protects simulanous deletes in list */
47 struct mutex lock;
48};
49
50struct caif_net {
51 struct cfcnfg *cfg;
52 struct caif_device_entry_list caifdevs;
53};
54
55static unsigned int caif_net_id;
56static int q_high = 50; /* Percent */
57
58struct cfcnfg *get_cfcnfg(struct net *net)
59{
60 struct caif_net *caifn;
61 caifn = net_generic(net, caif_net_id);
62 return caifn->cfg;
63}
64EXPORT_SYMBOL(get_cfcnfg);
65
66static struct caif_device_entry_list *caif_device_list(struct net *net)
67{
68 struct caif_net *caifn;
69 caifn = net_generic(net, caif_net_id);
70 return &caifn->caifdevs;
71}
72
73static void caifd_put(struct caif_device_entry *e)
74{
75 this_cpu_dec(*e->pcpu_refcnt);
76}
77
78static void caifd_hold(struct caif_device_entry *e)
79{
80 this_cpu_inc(*e->pcpu_refcnt);
81}
82
83static int caifd_refcnt_read(struct caif_device_entry *e)
84{
85 int i, refcnt = 0;
86 for_each_possible_cpu(i)
87 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
88 return refcnt;
89}
90
91/* Allocate new CAIF device. */
92static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
93{
94 struct caif_device_entry *caifd;
95
96 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
97 if (!caifd)
98 return NULL;
99 caifd->pcpu_refcnt = alloc_percpu(int);
100 if (!caifd->pcpu_refcnt) {
101 kfree(caifd);
102 return NULL;
103 }
104 caifd->netdev = dev;
105 dev_hold(dev);
106 return caifd;
107}
108
109static struct caif_device_entry *caif_get(struct net_device *dev)
110{
111 struct caif_device_entry_list *caifdevs =
112 caif_device_list(dev_net(dev));
113 struct caif_device_entry *caifd;
114
115 list_for_each_entry_rcu(caifd, &caifdevs->list, list,
116 lockdep_rtnl_is_held()) {
117 if (caifd->netdev == dev)
118 return caifd;
119 }
120 return NULL;
121}
122
123static void caif_flow_cb(struct sk_buff *skb)
124{
125 struct caif_device_entry *caifd;
126 void (*dtor)(struct sk_buff *skb) = NULL;
127 bool send_xoff;
128
129 WARN_ON(skb->dev == NULL);
130
131 rcu_read_lock();
132 caifd = caif_get(skb->dev);
133
134 WARN_ON(caifd == NULL);
135 if (!caifd) {
136 rcu_read_unlock();
137 return;
138 }
139
140 caifd_hold(caifd);
141 rcu_read_unlock();
142
143 spin_lock_bh(&caifd->flow_lock);
144 send_xoff = caifd->xoff;
145 caifd->xoff = false;
146 dtor = caifd->xoff_skb_dtor;
147
148 if (WARN_ON(caifd->xoff_skb != skb))
149 skb = NULL;
150
151 caifd->xoff_skb = NULL;
152 caifd->xoff_skb_dtor = NULL;
153
154 spin_unlock_bh(&caifd->flow_lock);
155
156 if (dtor && skb)
157 dtor(skb);
158
159 if (send_xoff)
160 caifd->layer.up->
161 ctrlcmd(caifd->layer.up,
162 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
163 caifd->layer.id);
164 caifd_put(caifd);
165}
166
167static int transmit(struct cflayer *layer, struct cfpkt *pkt)
168{
169 int err, high = 0, qlen = 0;
170 struct caif_device_entry *caifd =
171 container_of(layer, struct caif_device_entry, layer);
172 struct sk_buff *skb;
173 struct netdev_queue *txq;
174
175 rcu_read_lock_bh();
176
177 skb = cfpkt_tonative(pkt);
178 skb->dev = caifd->netdev;
179 skb_reset_network_header(skb);
180 skb->protocol = htons(ETH_P_CAIF);
181
182 /* Check if we need to handle xoff */
183 if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
184 goto noxoff;
185
186 if (unlikely(caifd->xoff))
187 goto noxoff;
188
189 if (likely(!netif_queue_stopped(caifd->netdev))) {
190 struct Qdisc *sch;
191
192 /* If we run with a TX queue, check if the queue is too long*/
193 txq = netdev_get_tx_queue(skb->dev, 0);
194 sch = rcu_dereference_bh(txq->qdisc);
195 if (likely(qdisc_is_empty(sch)))
196 goto noxoff;
197
198 /* can check for explicit qdisc len value only !NOLOCK,
199 * always set flow off otherwise
200 */
201 high = (caifd->netdev->tx_queue_len * q_high) / 100;
202 if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
203 goto noxoff;
204 }
205
206 /* Hold lock while accessing xoff */
207 spin_lock_bh(&caifd->flow_lock);
208 if (caifd->xoff) {
209 spin_unlock_bh(&caifd->flow_lock);
210 goto noxoff;
211 }
212
213 /*
214 * Handle flow off, we do this by temporary hi-jacking this
215 * skb's destructor function, and replace it with our own
216 * flow-on callback. The callback will set flow-on and call
217 * the original destructor.
218 */
219
220 pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
221 netif_queue_stopped(caifd->netdev),
222 qlen, high);
223 caifd->xoff = true;
224 caifd->xoff_skb = skb;
225 caifd->xoff_skb_dtor = skb->destructor;
226 skb->destructor = caif_flow_cb;
227 spin_unlock_bh(&caifd->flow_lock);
228
229 caifd->layer.up->ctrlcmd(caifd->layer.up,
230 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
231 caifd->layer.id);
232noxoff:
233 rcu_read_unlock_bh();
234
235 err = dev_queue_xmit(skb);
236 if (err > 0)
237 err = -EIO;
238
239 return err;
240}
241
242/*
243 * Stuff received packets into the CAIF stack.
244 * On error, returns non-zero and releases the skb.
245 */
246static int receive(struct sk_buff *skb, struct net_device *dev,
247 struct packet_type *pkttype, struct net_device *orig_dev)
248{
249 struct cfpkt *pkt;
250 struct caif_device_entry *caifd;
251 int err;
252
253 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
254
255 rcu_read_lock();
256 caifd = caif_get(dev);
257
258 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
259 !netif_oper_up(caifd->netdev)) {
260 rcu_read_unlock();
261 kfree_skb(skb);
262 return NET_RX_DROP;
263 }
264
265 /* Hold reference to netdevice while using CAIF stack */
266 caifd_hold(caifd);
267 rcu_read_unlock();
268
269 err = caifd->layer.up->receive(caifd->layer.up, pkt);
270
271 /* For -EILSEQ the packet is not freed so free it now */
272 if (err == -EILSEQ)
273 cfpkt_destroy(pkt);
274
275 /* Release reference to stack upwards */
276 caifd_put(caifd);
277
278 if (err != 0)
279 err = NET_RX_DROP;
280 return err;
281}
282
283static struct packet_type caif_packet_type __read_mostly = {
284 .type = cpu_to_be16(ETH_P_CAIF),
285 .func = receive,
286};
287
288static void dev_flowctrl(struct net_device *dev, int on)
289{
290 struct caif_device_entry *caifd;
291
292 rcu_read_lock();
293
294 caifd = caif_get(dev);
295 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
296 rcu_read_unlock();
297 return;
298 }
299
300 caifd_hold(caifd);
301 rcu_read_unlock();
302
303 caifd->layer.up->ctrlcmd(caifd->layer.up,
304 on ?
305 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
306 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
307 caifd->layer.id);
308 caifd_put(caifd);
309}
310
311int caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
312 struct cflayer *link_support, int head_room,
313 struct cflayer **layer,
314 int (**rcv_func)(struct sk_buff *, struct net_device *,
315 struct packet_type *,
316 struct net_device *))
317{
318 struct caif_device_entry *caifd;
319 enum cfcnfg_phy_preference pref;
320 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
321 struct caif_device_entry_list *caifdevs;
322 int res;
323
324 caifdevs = caif_device_list(dev_net(dev));
325 caifd = caif_device_alloc(dev);
326 if (!caifd)
327 return -ENOMEM;
328 *layer = &caifd->layer;
329 spin_lock_init(&caifd->flow_lock);
330
331 switch (caifdev->link_select) {
332 case CAIF_LINK_HIGH_BANDW:
333 pref = CFPHYPREF_HIGH_BW;
334 break;
335 case CAIF_LINK_LOW_LATENCY:
336 pref = CFPHYPREF_LOW_LAT;
337 break;
338 default:
339 pref = CFPHYPREF_HIGH_BW;
340 break;
341 }
342 mutex_lock(&caifdevs->lock);
343 list_add_rcu(&caifd->list, &caifdevs->list);
344
345 strscpy(caifd->layer.name, dev->name,
346 sizeof(caifd->layer.name));
347 caifd->layer.transmit = transmit;
348 res = cfcnfg_add_phy_layer(cfg,
349 dev,
350 &caifd->layer,
351 pref,
352 link_support,
353 caifdev->use_fcs,
354 head_room);
355 mutex_unlock(&caifdevs->lock);
356 if (rcv_func)
357 *rcv_func = receive;
358 return res;
359}
360EXPORT_SYMBOL(caif_enroll_dev);
361
362/* notify Caif of device events */
363static int caif_device_notify(struct notifier_block *me, unsigned long what,
364 void *ptr)
365{
366 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
367 struct caif_device_entry *caifd = NULL;
368 struct caif_dev_common *caifdev;
369 struct cfcnfg *cfg;
370 struct cflayer *layer, *link_support;
371 int head_room = 0;
372 struct caif_device_entry_list *caifdevs;
373 int res;
374
375 cfg = get_cfcnfg(dev_net(dev));
376 caifdevs = caif_device_list(dev_net(dev));
377
378 caifd = caif_get(dev);
379 if (caifd == NULL && dev->type != ARPHRD_CAIF)
380 return 0;
381
382 switch (what) {
383 case NETDEV_REGISTER:
384 if (caifd != NULL)
385 break;
386
387 caifdev = netdev_priv(dev);
388
389 link_support = NULL;
390 if (caifdev->use_frag) {
391 head_room = 1;
392 link_support = cfserl_create(dev->ifindex,
393 caifdev->use_stx);
394 if (!link_support) {
395 pr_warn("Out of memory\n");
396 break;
397 }
398 }
399 res = caif_enroll_dev(dev, caifdev, link_support, head_room,
400 &layer, NULL);
401 if (res)
402 cfserl_release(link_support);
403 caifdev->flowctrl = dev_flowctrl;
404 break;
405
406 case NETDEV_UP:
407 rcu_read_lock();
408
409 caifd = caif_get(dev);
410 if (caifd == NULL) {
411 rcu_read_unlock();
412 break;
413 }
414
415 caifd->xoff = false;
416 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
417 rcu_read_unlock();
418
419 break;
420
421 case NETDEV_DOWN:
422 rcu_read_lock();
423
424 caifd = caif_get(dev);
425 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
426 rcu_read_unlock();
427 return -EINVAL;
428 }
429
430 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
431 caifd_hold(caifd);
432 rcu_read_unlock();
433
434 caifd->layer.up->ctrlcmd(caifd->layer.up,
435 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
436 caifd->layer.id);
437
438 spin_lock_bh(&caifd->flow_lock);
439
440 /*
441 * Replace our xoff-destructor with original destructor.
442 * We trust that skb->destructor *always* is called before
443 * the skb reference is invalid. The hijacked SKB destructor
444 * takes the flow_lock so manipulating the skb->destructor here
445 * should be safe.
446 */
447 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
448 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
449
450 caifd->xoff = false;
451 caifd->xoff_skb_dtor = NULL;
452 caifd->xoff_skb = NULL;
453
454 spin_unlock_bh(&caifd->flow_lock);
455 caifd_put(caifd);
456 break;
457
458 case NETDEV_UNREGISTER:
459 mutex_lock(&caifdevs->lock);
460
461 caifd = caif_get(dev);
462 if (caifd == NULL) {
463 mutex_unlock(&caifdevs->lock);
464 break;
465 }
466 list_del_rcu(&caifd->list);
467
468 /*
469 * NETDEV_UNREGISTER is called repeatedly until all reference
470 * counts for the net-device are released. If references to
471 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
472 * the next call to NETDEV_UNREGISTER.
473 *
474 * If any packets are in flight down the CAIF Stack,
475 * cfcnfg_del_phy_layer will return nonzero.
476 * If no packets are in flight, the CAIF Stack associated
477 * with the net-device un-registering is freed.
478 */
479
480 if (caifd_refcnt_read(caifd) != 0 ||
481 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
482
483 pr_info("Wait for device inuse\n");
484 /* Enrole device if CAIF Stack is still in use */
485 list_add_rcu(&caifd->list, &caifdevs->list);
486 mutex_unlock(&caifdevs->lock);
487 break;
488 }
489
490 synchronize_rcu();
491 dev_put(caifd->netdev);
492 free_percpu(caifd->pcpu_refcnt);
493 kfree(caifd);
494
495 mutex_unlock(&caifdevs->lock);
496 break;
497 }
498 return 0;
499}
500
501static struct notifier_block caif_device_notifier = {
502 .notifier_call = caif_device_notify,
503 .priority = 0,
504};
505
506/* Per-namespace Caif devices handling */
507static int caif_init_net(struct net *net)
508{
509 struct caif_net *caifn = net_generic(net, caif_net_id);
510 INIT_LIST_HEAD(&caifn->caifdevs.list);
511 mutex_init(&caifn->caifdevs.lock);
512
513 caifn->cfg = cfcnfg_create();
514 if (!caifn->cfg)
515 return -ENOMEM;
516
517 return 0;
518}
519
520static void caif_exit_net(struct net *net)
521{
522 struct caif_device_entry *caifd, *tmp;
523 struct caif_device_entry_list *caifdevs =
524 caif_device_list(net);
525 struct cfcnfg *cfg = get_cfcnfg(net);
526
527 rtnl_lock();
528 mutex_lock(&caifdevs->lock);
529
530 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
531 int i = 0;
532 list_del_rcu(&caifd->list);
533 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
534
535 while (i < 10 &&
536 (caifd_refcnt_read(caifd) != 0 ||
537 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
538
539 pr_info("Wait for device inuse\n");
540 msleep(250);
541 i++;
542 }
543 synchronize_rcu();
544 dev_put(caifd->netdev);
545 free_percpu(caifd->pcpu_refcnt);
546 kfree(caifd);
547 }
548 cfcnfg_remove(cfg);
549
550 mutex_unlock(&caifdevs->lock);
551 rtnl_unlock();
552}
553
554static struct pernet_operations caif_net_ops = {
555 .init = caif_init_net,
556 .exit = caif_exit_net,
557 .id = &caif_net_id,
558 .size = sizeof(struct caif_net),
559};
560
561/* Initialize Caif devices list */
562static int __init caif_device_init(void)
563{
564 int result;
565
566 result = register_pernet_subsys(&caif_net_ops);
567
568 if (result)
569 return result;
570
571 register_netdevice_notifier(&caif_device_notifier);
572 dev_add_pack(&caif_packet_type);
573
574 return result;
575}
576
577static void __exit caif_device_exit(void)
578{
579 unregister_netdevice_notifier(&caif_device_notifier);
580 dev_remove_pack(&caif_packet_type);
581 unregister_pernet_subsys(&caif_net_ops);
582}
583
584module_init(caif_device_init);
585module_exit(caif_device_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CAIF Interface registration.
4 * Copyright (C) ST-Ericsson AB 2010
5 * Author: Sjur Brendeland
6 *
7 * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
8 * and Sakari Ailus <sakari.ailus@nokia.com>
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
12
13#include <linux/kernel.h>
14#include <linux/if_arp.h>
15#include <linux/net.h>
16#include <linux/netdevice.h>
17#include <linux/mutex.h>
18#include <linux/module.h>
19#include <linux/spinlock.h>
20#include <net/netns/generic.h>
21#include <net/net_namespace.h>
22#include <net/pkt_sched.h>
23#include <net/caif/caif_device.h>
24#include <net/caif/caif_layer.h>
25#include <net/caif/caif_dev.h>
26#include <net/caif/cfpkt.h>
27#include <net/caif/cfcnfg.h>
28#include <net/caif/cfserl.h>
29
30MODULE_LICENSE("GPL");
31
32/* Used for local tracking of the CAIF net devices */
33struct caif_device_entry {
34 struct cflayer layer;
35 struct list_head list;
36 struct net_device *netdev;
37 int __percpu *pcpu_refcnt;
38 spinlock_t flow_lock;
39 struct sk_buff *xoff_skb;
40 void (*xoff_skb_dtor)(struct sk_buff *skb);
41 bool xoff;
42};
43
44struct caif_device_entry_list {
45 struct list_head list;
46 /* Protects simulanous deletes in list */
47 struct mutex lock;
48};
49
50struct caif_net {
51 struct cfcnfg *cfg;
52 struct caif_device_entry_list caifdevs;
53};
54
55static unsigned int caif_net_id;
56static int q_high = 50; /* Percent */
57
58struct cfcnfg *get_cfcnfg(struct net *net)
59{
60 struct caif_net *caifn;
61 caifn = net_generic(net, caif_net_id);
62 return caifn->cfg;
63}
64EXPORT_SYMBOL(get_cfcnfg);
65
66static struct caif_device_entry_list *caif_device_list(struct net *net)
67{
68 struct caif_net *caifn;
69 caifn = net_generic(net, caif_net_id);
70 return &caifn->caifdevs;
71}
72
73static void caifd_put(struct caif_device_entry *e)
74{
75 this_cpu_dec(*e->pcpu_refcnt);
76}
77
78static void caifd_hold(struct caif_device_entry *e)
79{
80 this_cpu_inc(*e->pcpu_refcnt);
81}
82
83static int caifd_refcnt_read(struct caif_device_entry *e)
84{
85 int i, refcnt = 0;
86 for_each_possible_cpu(i)
87 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
88 return refcnt;
89}
90
91/* Allocate new CAIF device. */
92static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
93{
94 struct caif_device_entry *caifd;
95
96 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
97 if (!caifd)
98 return NULL;
99 caifd->pcpu_refcnt = alloc_percpu(int);
100 if (!caifd->pcpu_refcnt) {
101 kfree(caifd);
102 return NULL;
103 }
104 caifd->netdev = dev;
105 dev_hold(dev);
106 return caifd;
107}
108
109static struct caif_device_entry *caif_get(struct net_device *dev)
110{
111 struct caif_device_entry_list *caifdevs =
112 caif_device_list(dev_net(dev));
113 struct caif_device_entry *caifd;
114
115 list_for_each_entry_rcu(caifd, &caifdevs->list, list,
116 lockdep_rtnl_is_held()) {
117 if (caifd->netdev == dev)
118 return caifd;
119 }
120 return NULL;
121}
122
123static void caif_flow_cb(struct sk_buff *skb)
124{
125 struct caif_device_entry *caifd;
126 void (*dtor)(struct sk_buff *skb) = NULL;
127 bool send_xoff;
128
129 WARN_ON(skb->dev == NULL);
130
131 rcu_read_lock();
132 caifd = caif_get(skb->dev);
133
134 WARN_ON(caifd == NULL);
135 if (!caifd) {
136 rcu_read_unlock();
137 return;
138 }
139
140 caifd_hold(caifd);
141 rcu_read_unlock();
142
143 spin_lock_bh(&caifd->flow_lock);
144 send_xoff = caifd->xoff;
145 caifd->xoff = false;
146 dtor = caifd->xoff_skb_dtor;
147
148 if (WARN_ON(caifd->xoff_skb != skb))
149 skb = NULL;
150
151 caifd->xoff_skb = NULL;
152 caifd->xoff_skb_dtor = NULL;
153
154 spin_unlock_bh(&caifd->flow_lock);
155
156 if (dtor && skb)
157 dtor(skb);
158
159 if (send_xoff)
160 caifd->layer.up->
161 ctrlcmd(caifd->layer.up,
162 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
163 caifd->layer.id);
164 caifd_put(caifd);
165}
166
167static int transmit(struct cflayer *layer, struct cfpkt *pkt)
168{
169 int err, high = 0, qlen = 0;
170 struct caif_device_entry *caifd =
171 container_of(layer, struct caif_device_entry, layer);
172 struct sk_buff *skb;
173 struct netdev_queue *txq;
174
175 rcu_read_lock_bh();
176
177 skb = cfpkt_tonative(pkt);
178 skb->dev = caifd->netdev;
179 skb_reset_network_header(skb);
180 skb->protocol = htons(ETH_P_CAIF);
181
182 /* Check if we need to handle xoff */
183 if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
184 goto noxoff;
185
186 if (unlikely(caifd->xoff))
187 goto noxoff;
188
189 if (likely(!netif_queue_stopped(caifd->netdev))) {
190 struct Qdisc *sch;
191
192 /* If we run with a TX queue, check if the queue is too long*/
193 txq = netdev_get_tx_queue(skb->dev, 0);
194 sch = rcu_dereference_bh(txq->qdisc);
195 if (likely(qdisc_is_empty(sch)))
196 goto noxoff;
197
198 /* can check for explicit qdisc len value only !NOLOCK,
199 * always set flow off otherwise
200 */
201 high = (caifd->netdev->tx_queue_len * q_high) / 100;
202 if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high))
203 goto noxoff;
204 }
205
206 /* Hold lock while accessing xoff */
207 spin_lock_bh(&caifd->flow_lock);
208 if (caifd->xoff) {
209 spin_unlock_bh(&caifd->flow_lock);
210 goto noxoff;
211 }
212
213 /*
214 * Handle flow off, we do this by temporary hi-jacking this
215 * skb's destructor function, and replace it with our own
216 * flow-on callback. The callback will set flow-on and call
217 * the original destructor.
218 */
219
220 pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
221 netif_queue_stopped(caifd->netdev),
222 qlen, high);
223 caifd->xoff = true;
224 caifd->xoff_skb = skb;
225 caifd->xoff_skb_dtor = skb->destructor;
226 skb->destructor = caif_flow_cb;
227 spin_unlock_bh(&caifd->flow_lock);
228
229 caifd->layer.up->ctrlcmd(caifd->layer.up,
230 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
231 caifd->layer.id);
232noxoff:
233 rcu_read_unlock_bh();
234
235 err = dev_queue_xmit(skb);
236 if (err > 0)
237 err = -EIO;
238
239 return err;
240}
241
242/*
243 * Stuff received packets into the CAIF stack.
244 * On error, returns non-zero and releases the skb.
245 */
246static int receive(struct sk_buff *skb, struct net_device *dev,
247 struct packet_type *pkttype, struct net_device *orig_dev)
248{
249 struct cfpkt *pkt;
250 struct caif_device_entry *caifd;
251 int err;
252
253 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
254
255 rcu_read_lock();
256 caifd = caif_get(dev);
257
258 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
259 !netif_oper_up(caifd->netdev)) {
260 rcu_read_unlock();
261 kfree_skb(skb);
262 return NET_RX_DROP;
263 }
264
265 /* Hold reference to netdevice while using CAIF stack */
266 caifd_hold(caifd);
267 rcu_read_unlock();
268
269 err = caifd->layer.up->receive(caifd->layer.up, pkt);
270
271 /* For -EILSEQ the packet is not freed so so it now */
272 if (err == -EILSEQ)
273 cfpkt_destroy(pkt);
274
275 /* Release reference to stack upwards */
276 caifd_put(caifd);
277
278 if (err != 0)
279 err = NET_RX_DROP;
280 return err;
281}
282
283static struct packet_type caif_packet_type __read_mostly = {
284 .type = cpu_to_be16(ETH_P_CAIF),
285 .func = receive,
286};
287
288static void dev_flowctrl(struct net_device *dev, int on)
289{
290 struct caif_device_entry *caifd;
291
292 rcu_read_lock();
293
294 caifd = caif_get(dev);
295 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
296 rcu_read_unlock();
297 return;
298 }
299
300 caifd_hold(caifd);
301 rcu_read_unlock();
302
303 caifd->layer.up->ctrlcmd(caifd->layer.up,
304 on ?
305 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
306 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
307 caifd->layer.id);
308 caifd_put(caifd);
309}
310
311void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
312 struct cflayer *link_support, int head_room,
313 struct cflayer **layer,
314 int (**rcv_func)(struct sk_buff *, struct net_device *,
315 struct packet_type *,
316 struct net_device *))
317{
318 struct caif_device_entry *caifd;
319 enum cfcnfg_phy_preference pref;
320 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
321 struct caif_device_entry_list *caifdevs;
322
323 caifdevs = caif_device_list(dev_net(dev));
324 caifd = caif_device_alloc(dev);
325 if (!caifd)
326 return;
327 *layer = &caifd->layer;
328 spin_lock_init(&caifd->flow_lock);
329
330 switch (caifdev->link_select) {
331 case CAIF_LINK_HIGH_BANDW:
332 pref = CFPHYPREF_HIGH_BW;
333 break;
334 case CAIF_LINK_LOW_LATENCY:
335 pref = CFPHYPREF_LOW_LAT;
336 break;
337 default:
338 pref = CFPHYPREF_HIGH_BW;
339 break;
340 }
341 mutex_lock(&caifdevs->lock);
342 list_add_rcu(&caifd->list, &caifdevs->list);
343
344 strlcpy(caifd->layer.name, dev->name,
345 sizeof(caifd->layer.name));
346 caifd->layer.transmit = transmit;
347 cfcnfg_add_phy_layer(cfg,
348 dev,
349 &caifd->layer,
350 pref,
351 link_support,
352 caifdev->use_fcs,
353 head_room);
354 mutex_unlock(&caifdevs->lock);
355 if (rcv_func)
356 *rcv_func = receive;
357}
358EXPORT_SYMBOL(caif_enroll_dev);
359
360/* notify Caif of device events */
361static int caif_device_notify(struct notifier_block *me, unsigned long what,
362 void *ptr)
363{
364 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
365 struct caif_device_entry *caifd = NULL;
366 struct caif_dev_common *caifdev;
367 struct cfcnfg *cfg;
368 struct cflayer *layer, *link_support;
369 int head_room = 0;
370 struct caif_device_entry_list *caifdevs;
371
372 cfg = get_cfcnfg(dev_net(dev));
373 caifdevs = caif_device_list(dev_net(dev));
374
375 caifd = caif_get(dev);
376 if (caifd == NULL && dev->type != ARPHRD_CAIF)
377 return 0;
378
379 switch (what) {
380 case NETDEV_REGISTER:
381 if (caifd != NULL)
382 break;
383
384 caifdev = netdev_priv(dev);
385
386 link_support = NULL;
387 if (caifdev->use_frag) {
388 head_room = 1;
389 link_support = cfserl_create(dev->ifindex,
390 caifdev->use_stx);
391 if (!link_support) {
392 pr_warn("Out of memory\n");
393 break;
394 }
395 }
396 caif_enroll_dev(dev, caifdev, link_support, head_room,
397 &layer, NULL);
398 caifdev->flowctrl = dev_flowctrl;
399 break;
400
401 case NETDEV_UP:
402 rcu_read_lock();
403
404 caifd = caif_get(dev);
405 if (caifd == NULL) {
406 rcu_read_unlock();
407 break;
408 }
409
410 caifd->xoff = false;
411 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
412 rcu_read_unlock();
413
414 break;
415
416 case NETDEV_DOWN:
417 rcu_read_lock();
418
419 caifd = caif_get(dev);
420 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
421 rcu_read_unlock();
422 return -EINVAL;
423 }
424
425 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
426 caifd_hold(caifd);
427 rcu_read_unlock();
428
429 caifd->layer.up->ctrlcmd(caifd->layer.up,
430 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
431 caifd->layer.id);
432
433 spin_lock_bh(&caifd->flow_lock);
434
435 /*
436 * Replace our xoff-destructor with original destructor.
437 * We trust that skb->destructor *always* is called before
438 * the skb reference is invalid. The hijacked SKB destructor
439 * takes the flow_lock so manipulating the skb->destructor here
440 * should be safe.
441 */
442 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
443 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
444
445 caifd->xoff = false;
446 caifd->xoff_skb_dtor = NULL;
447 caifd->xoff_skb = NULL;
448
449 spin_unlock_bh(&caifd->flow_lock);
450 caifd_put(caifd);
451 break;
452
453 case NETDEV_UNREGISTER:
454 mutex_lock(&caifdevs->lock);
455
456 caifd = caif_get(dev);
457 if (caifd == NULL) {
458 mutex_unlock(&caifdevs->lock);
459 break;
460 }
461 list_del_rcu(&caifd->list);
462
463 /*
464 * NETDEV_UNREGISTER is called repeatedly until all reference
465 * counts for the net-device are released. If references to
466 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
467 * the next call to NETDEV_UNREGISTER.
468 *
469 * If any packets are in flight down the CAIF Stack,
470 * cfcnfg_del_phy_layer will return nonzero.
471 * If no packets are in flight, the CAIF Stack associated
472 * with the net-device un-registering is freed.
473 */
474
475 if (caifd_refcnt_read(caifd) != 0 ||
476 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
477
478 pr_info("Wait for device inuse\n");
479 /* Enrole device if CAIF Stack is still in use */
480 list_add_rcu(&caifd->list, &caifdevs->list);
481 mutex_unlock(&caifdevs->lock);
482 break;
483 }
484
485 synchronize_rcu();
486 dev_put(caifd->netdev);
487 free_percpu(caifd->pcpu_refcnt);
488 kfree(caifd);
489
490 mutex_unlock(&caifdevs->lock);
491 break;
492 }
493 return 0;
494}
495
496static struct notifier_block caif_device_notifier = {
497 .notifier_call = caif_device_notify,
498 .priority = 0,
499};
500
501/* Per-namespace Caif devices handling */
502static int caif_init_net(struct net *net)
503{
504 struct caif_net *caifn = net_generic(net, caif_net_id);
505 INIT_LIST_HEAD(&caifn->caifdevs.list);
506 mutex_init(&caifn->caifdevs.lock);
507
508 caifn->cfg = cfcnfg_create();
509 if (!caifn->cfg)
510 return -ENOMEM;
511
512 return 0;
513}
514
515static void caif_exit_net(struct net *net)
516{
517 struct caif_device_entry *caifd, *tmp;
518 struct caif_device_entry_list *caifdevs =
519 caif_device_list(net);
520 struct cfcnfg *cfg = get_cfcnfg(net);
521
522 rtnl_lock();
523 mutex_lock(&caifdevs->lock);
524
525 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
526 int i = 0;
527 list_del_rcu(&caifd->list);
528 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
529
530 while (i < 10 &&
531 (caifd_refcnt_read(caifd) != 0 ||
532 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
533
534 pr_info("Wait for device inuse\n");
535 msleep(250);
536 i++;
537 }
538 synchronize_rcu();
539 dev_put(caifd->netdev);
540 free_percpu(caifd->pcpu_refcnt);
541 kfree(caifd);
542 }
543 cfcnfg_remove(cfg);
544
545 mutex_unlock(&caifdevs->lock);
546 rtnl_unlock();
547}
548
549static struct pernet_operations caif_net_ops = {
550 .init = caif_init_net,
551 .exit = caif_exit_net,
552 .id = &caif_net_id,
553 .size = sizeof(struct caif_net),
554};
555
556/* Initialize Caif devices list */
557static int __init caif_device_init(void)
558{
559 int result;
560
561 result = register_pernet_subsys(&caif_net_ops);
562
563 if (result)
564 return result;
565
566 register_netdevice_notifier(&caif_device_notifier);
567 dev_add_pack(&caif_packet_type);
568
569 return result;
570}
571
572static void __exit caif_device_exit(void)
573{
574 unregister_netdevice_notifier(&caif_device_notifier);
575 dev_remove_pack(&caif_packet_type);
576 unregister_pernet_subsys(&caif_net_ops);
577}
578
579module_init(caif_device_init);
580module_exit(caif_device_exit);