aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/hw/ipath/ipath_verbs_mcast.c
blob: 10b31d2c4f20977b82988cdab304b250b317abf6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
/*
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/list.h>
#include <linux/rcupdate.h>

#include "ipath_verbs.h"

/*
 * Global table of GID to attached QPs.
 * The table is global to all ipath devices since a send from one QP/device
 * needs to be locally routed to any locally attached QPs on the same
 * or different device.
 */
static struct rb_root mcast_tree;
static DEFINE_SPINLOCK(mcast_lock);

/**
 * ipath_mcast_qp_alloc - alloc a struct to link a QP to mcast GID struct
 * @qp: the QP to link
 */
static struct ipath_mcast_qp *ipath_mcast_qp_alloc(struct ipath_qp *qp)
{
	struct ipath_mcast_qp *mqp;

	mqp = kmalloc(sizeof *mqp, GFP_KERNEL);
	if (!mqp)
		goto bail;

	mqp->qp = qp;
	atomic_inc(&qp->refcount);

bail:
	return mqp;
}

static void ipath_mcast_qp_free(struct ipath_mcast_qp *mqp)
{
	struct ipath_qp *qp = mqp->qp;

	/* Notify ipath_destroy_qp() if it is waiting. */
	if (atomic_dec_and_test(&qp->refcount))
		wake_up(&qp->wait);

	kfree(mqp);
}

/**
 * ipath_mcast_alloc - allocate the multicast GID structure
 * @mgid: the multicast GID
 *
 * A list of QPs will be attached to this structure.
 */
static struct ipath_mcast *ipath_mcast_alloc(union ib_gid *mgid)
{
	struct ipath_mcast *mcast;

	mcast = kmalloc(sizeof *mcast, GFP_KERNEL);
	if (!mcast)
		goto bail;

	mcast->mgid = *mgid;
	INIT_LIST_HEAD(&mcast->qp_list);
	init_waitqueue_head(&mcast->wait);
	atomic_set(&mcast->refcount, 0);

bail:
	return mcast;
}

static void ipath_mcast_free(struct ipath_mcast *mcast)
{
	struct ipath_mcast_qp *p, *tmp;

	list_for_each_entry_safe(p, tmp, &mcast->qp_list, list)
		ipath_mcast_qp_free(p);

	kfree(mcast);
}

/**
 * ipath_mcast_find - search the global table for the given multicast GID
 * @mgid: the multicast GID to search for
 *
 * Returns NULL if not found.
 *
 * The caller is responsible for decrementing the reference count if found.
 */
struct ipath_mcast *ipath_mcast_find(union ib_gid *mgid)
{
	struct rb_node *n;
	unsigned long flags;
	struct ipath_mcast *mcast;

	spin_lock_irqsave(&mcast_lock, flags);
	n = mcast_tree.rb_node;
	while (n) {
		int ret;

		mcast = rb_entry(n, struct ipath_mcast, rb_node);

		ret = memcmp(mgid->raw, mcast->mgid.raw,
			     sizeof(union ib_gid));
		if (ret < 0)
			n = n->rb_left;
		else if (ret > 0)
			n = n->rb_right;
		else {
			atomic_inc(&mcast->refcount);
			spin_unlock_irqrestore(&mcast_lock, flags);
			goto bail;
		}
	}
	spin_unlock_irqrestore(&mcast_lock, flags);

	mcast = NULL;

bail:
	return mcast;
}

/**
 * ipath_mcast_add - insert mcast GID into table and attach QP struct
 * @mcast: the mcast GID table
 * @mqp: the QP to attach
 *
 * Return zero if both were added.  Return EEXIST if the GID was already in
 * the table but the QP was added.  Return ESRCH if the QP was already
 * attached and neither structure was added.
 */
static int ipath_mcast_add(struct ipath_mcast *mcast,
			   struct ipath_mcast_qp *mqp)
{
	struct rb_node **n = &mcast_tree.rb_node;
	struct rb_node *pn = NULL;
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&mcast_lock, flags);

	while (*n) {
		struct ipath_mcast *tmcast;
		struct ipath_mcast_qp *p;

		pn = *n;
		tmcast = rb_entry(pn, struct ipath_mcast, rb_node);

		ret = memcmp(mcast->mgid.raw, tmcast->mgid.raw,
			     sizeof(union ib_gid));
		if (ret < 0) {
			n = &pn->rb_left;
			continue;
		}
		if (ret > 0) {
			n = &pn->rb_right;
			continue;
		}

		/* Search the QP list to see if this is already there. */
		list_for_each_entry_rcu(p, &tmcast->qp_list, list) {
			if (p->qp == mqp->qp) {
				spin_unlock_irqrestore(&mcast_lock, flags);
				ret = ESRCH;
				goto bail;
			}
		}
		list_add_tail_rcu(&mqp->list, &tmcast->qp_list);
		spin_unlock_irqrestore(&mcast_lock, flags);
		ret = EEXIST;
		goto bail;
	}

	list_add_tail_rcu(&mqp->list, &mcast->qp_list);

	atomic_inc(&mcast->refcount);
	rb_link_node(&mcast->rb_node, pn, n);
	rb_insert_color(&mcast->rb_node, &mcast_tree);

	spin_unlock_irqrestore(&mcast_lock, flags);

	ret = 0;

bail:
	return ret;
}

int ipath_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
{
	struct ipath_qp *qp = to_iqp(ibqp);
	struct ipath_mcast *mcast;
	struct ipath_mcast_qp *mqp;
	int ret;

	/*
	 * Allocate data structures since its better to do this outside of
	 * spin locks and it will most likely be needed.
	 */
	mcast = ipath_mcast_alloc(gid);
	if (mcast == NULL) {
		ret = -ENOMEM;
		goto bail;
	}
	mqp = ipath_mcast_qp_alloc(qp);
	if (mqp == NULL) {
		ipath_mcast_free(mcast);
		ret = -ENOMEM;
		goto bail;
	}
	switch (ipath_mcast_add(mcast, mqp)) {
	case ESRCH:
		/* Neither was used: can't attach the same QP twice. */
		ipath_mcast_qp_free(mqp);
		ipath_mcast_free(mcast);
		ret = -EINVAL;
		goto bail;
	case EEXIST:		/* The mcast wasn't used */
		ipath_mcast_free(mcast);
		break;
	default:
		break;
	}

	ret = 0;

bail:
	return ret;
}

int ipath_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
{
	struct ipath_qp *qp = to_iqp(ibqp);
	struct ipath_mcast *mcast = NULL;
	struct ipath_mcast_qp *p, *tmp;
	struct rb_node *n;
	unsigned long flags;
	int last = 0;
	int ret;

	spin_lock_irqsave(&mcast_lock, flags);

	/* Find the GID in the mcast table. */
	n = mcast_tree.rb_node;
	while (1) {
		if (n == NULL) {
			spin_unlock_irqrestore(&mcast_lock, flags);
			ret = 0;
			goto bail;
		}

		mcast = rb_entry(n, struct ipath_mcast, rb_node);
		ret = memcmp(gid->raw, mcast->mgid.raw,
			     sizeof(union ib_gid));
		if (ret < 0)
			n = n->rb_left;
		else if (ret > 0)
			n = n->rb_right;
		else
			break;
	}

	/* Search the QP list. */
	list_for_each_entry_safe(p, tmp, &mcast->qp_list, list) {
		if (p->qp != qp)
			continue;
		/*
		 * We found it, so remove it, but don't poison the forward
		 * link until we are sure there are no list walkers.
		 */
		list_del_rcu(&p->list);

		/* If this was the last attached QP, remove the GID too. */
		if (list_empty(&mcast->qp_list)) {
			rb_erase(&mcast->rb_node, &mcast_tree);
			last = 1;
		}
		break;
	}

	spin_unlock_irqrestore(&mcast_lock, flags);

	if (p) {
		/*
		 * Wait for any list walkers to finish before freeing the
		 * list element.
		 */
		wait_event(mcast->wait, atomic_read(&mcast->refcount) <= 1);
		ipath_mcast_qp_free(p);
	}
	if (last) {
		atomic_dec(&mcast->refcount);
		wait_event(mcast->wait, !atomic_read(&mcast->refcount));
		ipath_mcast_free(mcast);
	}

	ret = 0;

bail:
	return ret;
}

int ipath_mcast_tree_empty(void)
{
	return mcast_tree.rb_node == NULL;
}