1 /*
2  * Copyright(c) 2016 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 #include <linux/slab.h>
49 #include <linux/sched.h>
50 #include <linux/rculist.h>
51 #include <rdma/rdma_vt.h>
52 #include <rdma/rdmavt_qp.h>
53 
54 #include "mcast.h"
55 
56 /**
57  * rvt_driver_mcast - init resources for multicast
58  * @rdi: rvt dev struct
59  *
60  * This is per device that registers with rdmavt
61  */
62 void rvt_driver_mcast_init(struct rvt_dev_info *rdi)
63 {
64 	/*
65 	 * Anything that needs setup for multicast on a per driver or per rdi
66 	 * basis should be done in here.
67 	 */
68 	spin_lock_init(&rdi->n_mcast_grps_lock);
69 }
70 
71 /**
72  * mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
73  * @qp: the QP to link
74  */
75 static struct rvt_mcast_qp *rvt_mcast_qp_alloc(struct rvt_qp *qp)
76 {
77 	struct rvt_mcast_qp *mqp;
78 
79 	mqp = kmalloc(sizeof(*mqp), GFP_KERNEL);
80 	if (!mqp)
81 		goto bail;
82 
83 	mqp->qp = qp;
84 	rvt_get_qp(qp);
85 
86 bail:
87 	return mqp;
88 }
89 
90 static void rvt_mcast_qp_free(struct rvt_mcast_qp *mqp)
91 {
92 	struct rvt_qp *qp = mqp->qp;
93 
94 	/* Notify hfi1_destroy_qp() if it is waiting. */
95 	rvt_put_qp(qp);
96 
97 	kfree(mqp);
98 }
99 
100 /**
101  * mcast_alloc - allocate the multicast GID structure
102  * @mgid: the multicast GID
103  * @lid: the muilticast LID (host order)
104  *
105  * A list of QPs will be attached to this structure.
106  */
107 static struct rvt_mcast *rvt_mcast_alloc(union ib_gid *mgid, u16 lid)
108 {
109 	struct rvt_mcast *mcast;
110 
111 	mcast = kzalloc(sizeof(*mcast), GFP_KERNEL);
112 	if (!mcast)
113 		goto bail;
114 
115 	mcast->mcast_addr.mgid = *mgid;
116 	mcast->mcast_addr.lid = lid;
117 
118 	INIT_LIST_HEAD(&mcast->qp_list);
119 	init_waitqueue_head(&mcast->wait);
120 	atomic_set(&mcast->refcount, 0);
121 
122 bail:
123 	return mcast;
124 }
125 
126 static void rvt_mcast_free(struct rvt_mcast *mcast)
127 {
128 	struct rvt_mcast_qp *p, *tmp;
129 
130 	list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
131 		rvt_mcast_qp_free(p);
132 
133 	kfree(mcast);
134 }
135 
136 /**
137  * rvt_mcast_find - search the global table for the given multicast GID/LID
138  * NOTE: It is valid to have 1 MLID with multiple MGIDs.  It is not valid
139  * to have 1 MGID with multiple MLIDs.
140  * @ibp: the IB port structure
141  * @mgid: the multicast GID to search for
142  * @lid: the multicast LID portion of the multicast address (host order)
143  *
144  * The caller is responsible for decrementing the reference count if found.
145  *
146  * Return: NULL if not found.
147  */
148 struct rvt_mcast *rvt_mcast_find(struct rvt_ibport *ibp, union ib_gid *mgid,
149 				 u16 lid)
150 {
151 	struct rb_node *n;
152 	unsigned long flags;
153 	struct rvt_mcast *found = NULL;
154 
155 	spin_lock_irqsave(&ibp->lock, flags);
156 	n = ibp->mcast_tree.rb_node;
157 	while (n) {
158 		int ret;
159 		struct rvt_mcast *mcast;
160 
161 		mcast = rb_entry(n, struct rvt_mcast, rb_node);
162 
163 		ret = memcmp(mgid->raw, mcast->mcast_addr.mgid.raw,
164 			     sizeof(*mgid));
165 		if (ret < 0) {
166 			n = n->rb_left;
167 		} else if (ret > 0) {
168 			n = n->rb_right;
169 		} else {
170 			/* MGID/MLID must match */
171 			if (mcast->mcast_addr.lid == lid) {
172 				atomic_inc(&mcast->refcount);
173 				found = mcast;
174 			}
175 			break;
176 		}
177 	}
178 	spin_unlock_irqrestore(&ibp->lock, flags);
179 	return found;
180 }
181 EXPORT_SYMBOL(rvt_mcast_find);
182 
183 /**
184  * mcast_add - insert mcast GID into table and attach QP struct
185  * @mcast: the mcast GID table
186  * @mqp: the QP to attach
187  *
188  * Return: zero if both were added.  Return EEXIST if the GID was already in
189  * the table but the QP was added.  Return ESRCH if the QP was already
190  * attached and neither structure was added. Return EINVAL if the MGID was
191  * found, but the MLID did NOT match.
192  */
193 static int rvt_mcast_add(struct rvt_dev_info *rdi, struct rvt_ibport *ibp,
194 			 struct rvt_mcast *mcast, struct rvt_mcast_qp *mqp)
195 {
196 	struct rb_node **n = &ibp->mcast_tree.rb_node;
197 	struct rb_node *pn = NULL;
198 	int ret;
199 
200 	spin_lock_irq(&ibp->lock);
201 
202 	while (*n) {
203 		struct rvt_mcast *tmcast;
204 		struct rvt_mcast_qp *p;
205 
206 		pn = *n;
207 		tmcast = rb_entry(pn, struct rvt_mcast, rb_node);
208 
209 		ret = memcmp(mcast->mcast_addr.mgid.raw,
210 			     tmcast->mcast_addr.mgid.raw,
211 			     sizeof(mcast->mcast_addr.mgid));
212 		if (ret < 0) {
213 			n = &pn->rb_left;
214 			continue;
215 		}
216 		if (ret > 0) {
217 			n = &pn->rb_right;
218 			continue;
219 		}
220 
221 		if (tmcast->mcast_addr.lid != mcast->mcast_addr.lid) {
222 			ret = EINVAL;
223 			goto bail;
224 		}
225 
226 		/* Search the QP list to see if this is already there. */
227 		list_for_each_entry_rcu(p, &tmcast->qp_list, list) {
228 			if (p->qp == mqp->qp) {
229 				ret = ESRCH;
230 				goto bail;
231 			}
232 		}
233 		if (tmcast->n_attached ==
234 		    rdi->dparms.props.max_mcast_qp_attach) {
235 			ret = ENOMEM;
236 			goto bail;
237 		}
238 
239 		tmcast->n_attached++;
240 
241 		list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
242 		ret = EEXIST;
243 		goto bail;
244 	}
245 
246 	spin_lock(&rdi->n_mcast_grps_lock);
247 	if (rdi->n_mcast_grps_allocated == rdi->dparms.props.max_mcast_grp) {
248 		spin_unlock(&rdi->n_mcast_grps_lock);
249 		ret = ENOMEM;
250 		goto bail;
251 	}
252 
253 	rdi->n_mcast_grps_allocated++;
254 	spin_unlock(&rdi->n_mcast_grps_lock);
255 
256 	mcast->n_attached++;
257 
258 	list_add_tail_rcu(&mqp->list, &mcast->qp_list);
259 
260 	atomic_inc(&mcast->refcount);
261 	rb_link_node(&mcast->rb_node, pn, n);
262 	rb_insert_color(&mcast->rb_node, &ibp->mcast_tree);
263 
264 	ret = 0;
265 
266 bail:
267 	spin_unlock_irq(&ibp->lock);
268 
269 	return ret;
270 }
271 
272 /**
273  * rvt_attach_mcast - attach a qp to a multicast group
274  * @ibqp: Infiniband qp
275  * @gid: multicast guid
276  * @lid: multicast lid
277  *
278  * Return: 0 on success
279  */
280 int rvt_attach_mcast(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
281 {
282 	struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
283 	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
284 	struct rvt_ibport *ibp = rdi->ports[qp->port_num - 1];
285 	struct rvt_mcast *mcast;
286 	struct rvt_mcast_qp *mqp;
287 	int ret = -ENOMEM;
288 
289 	if (ibqp->qp_num <= 1 || qp->state == IB_QPS_RESET)
290 		return -EINVAL;
291 
292 	/*
293 	 * Allocate data structures since its better to do this outside of
294 	 * spin locks and it will most likely be needed.
295 	 */
296 	mcast = rvt_mcast_alloc(gid, lid);
297 	if (!mcast)
298 		return -ENOMEM;
299 
300 	mqp = rvt_mcast_qp_alloc(qp);
301 	if (!mqp)
302 		goto bail_mcast;
303 
304 	switch (rvt_mcast_add(rdi, ibp, mcast, mqp)) {
305 	case ESRCH:
306 		/* Neither was used: OK to attach the same QP twice. */
307 		ret = 0;
308 		goto bail_mqp;
309 	case EEXIST: /* The mcast wasn't used */
310 		ret = 0;
311 		goto bail_mcast;
312 	case ENOMEM:
313 		/* Exceeded the maximum number of mcast groups. */
314 		ret = -ENOMEM;
315 		goto bail_mqp;
316 	case EINVAL:
317 		/* Invalid MGID/MLID pair */
318 		ret = -EINVAL;
319 		goto bail_mqp;
320 	default:
321 		break;
322 	}
323 
324 	return 0;
325 
326 bail_mqp:
327 	rvt_mcast_qp_free(mqp);
328 
329 bail_mcast:
330 	rvt_mcast_free(mcast);
331 
332 	return ret;
333 }
334 
335 /**
336  * rvt_detach_mcast - remove a qp from a multicast group
337  * @ibqp: Infiniband qp
338  * @gid: multicast guid
339  * @lid: multicast lid
340  *
341  * Return: 0 on success
342  */
343 int rvt_detach_mcast(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
344 {
345 	struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
346 	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
347 	struct rvt_ibport *ibp = rdi->ports[qp->port_num - 1];
348 	struct rvt_mcast *mcast = NULL;
349 	struct rvt_mcast_qp *p, *tmp, *delp = NULL;
350 	struct rb_node *n;
351 	int last = 0;
352 	int ret = 0;
353 
354 	if (ibqp->qp_num <= 1)
355 		return -EINVAL;
356 
357 	spin_lock_irq(&ibp->lock);
358 
359 	/* Find the GID in the mcast table. */
360 	n = ibp->mcast_tree.rb_node;
361 	while (1) {
362 		if (!n) {
363 			spin_unlock_irq(&ibp->lock);
364 			return -EINVAL;
365 		}
366 
367 		mcast = rb_entry(n, struct rvt_mcast, rb_node);
368 		ret = memcmp(gid->raw, mcast->mcast_addr.mgid.raw,
369 			     sizeof(*gid));
370 		if (ret < 0) {
371 			n = n->rb_left;
372 		} else if (ret > 0) {
373 			n = n->rb_right;
374 		} else {
375 			/* MGID/MLID must match */
376 			if (mcast->mcast_addr.lid != lid) {
377 				spin_unlock_irq(&ibp->lock);
378 				return -EINVAL;
379 			}
380 			break;
381 		}
382 	}
383 
384 	/* Search the QP list. */
385 	list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
386 		if (p->qp != qp)
387 			continue;
388 		/*
389 		 * We found it, so remove it, but don't poison the forward
390 		 * link until we are sure there are no list walkers.
391 		 */
392 		list_del_rcu(&p->list);
393 		mcast->n_attached--;
394 		delp = p;
395 
396 		/* If this was the last attached QP, remove the GID too. */
397 		if (list_empty(&mcast->qp_list)) {
398 			rb_erase(&mcast->rb_node, &ibp->mcast_tree);
399 			last = 1;
400 		}
401 		break;
402 	}
403 
404 	spin_unlock_irq(&ibp->lock);
405 	/* QP not attached */
406 	if (!delp)
407 		return -EINVAL;
408 
409 	/*
410 	 * Wait for any list walkers to finish before freeing the
411 	 * list element.
412 	 */
413 	wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
414 	rvt_mcast_qp_free(delp);
415 
416 	if (last) {
417 		atomic_dec(&mcast->refcount);
418 		wait_event(mcast->wait, !atomic_read(&mcast->refcount));
419 		rvt_mcast_free(mcast);
420 		spin_lock_irq(&rdi->n_mcast_grps_lock);
421 		rdi->n_mcast_grps_allocated--;
422 		spin_unlock_irq(&rdi->n_mcast_grps_lock);
423 	}
424 
425 	return 0;
426 }
427 
428 /**
429  *rvt_mast_tree_empty - determine if any qps are attached to any mcast group
430  *@rdi: rvt dev struct
431  *
432  * Return: in use count
433  */
434 int rvt_mcast_tree_empty(struct rvt_dev_info *rdi)
435 {
436 	int i;
437 	int in_use = 0;
438 
439 	for (i = 0; i < rdi->dparms.nports; i++)
440 		if (rdi->ports[i]->mcast_tree.rb_node)
441 			in_use++;
442 	return in_use;
443 }
444