summaryrefslogtreecommitdiff
path: root/net/sctp/stream_sched_prio.c
blob: 4d4d9da331f4c3b06e45b767376ce8bb63c60cb5 (plain)
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
// SPDX-License-Identifier: GPL-2.0-or-later
/* SCTP kernel implementation
 * (C) Copyright Red Hat Inc. 2017
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions manipulate sctp stream queue/scheduling.
 *
 * Please send any bug reports or fixes you make to the
 * email addresched(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
 */

#include <linux/list.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/stream_sched.h>

/* Priority handling
 * RFC DRAFT ndata section 3.4
 */

static void sctp_sched_prio_unsched_all(struct sctp_stream *stream);

static struct sctp_stream_priorities *sctp_sched_prio_head_get(struct sctp_stream_priorities *p)
{
	p->users++;
	return p;
}

static void sctp_sched_prio_head_put(struct sctp_stream_priorities *p)
{
	if (p && --p->users == 0)
		kfree(p);
}

static struct sctp_stream_priorities *sctp_sched_prio_new_head(
			struct sctp_stream *stream, int prio, gfp_t gfp)
{
	struct sctp_stream_priorities *p;

	p = kmalloc(sizeof(*p), gfp);
	if (!p)
		return NULL;

	INIT_LIST_HEAD(&p->prio_sched);
	INIT_LIST_HEAD(&p->active);
	p->next = NULL;
	p->prio = prio;
	p->users = 1;

	return p;
}

static struct sctp_stream_priorities *sctp_sched_prio_get_head(
			struct sctp_stream *stream, int prio, gfp_t gfp)
{
	struct sctp_stream_priorities *p;
	int i;

	/* Look into scheduled priorities first, as they are sorted and
	 * we can find it fast IF it's scheduled.
	 */
	list_for_each_entry(p, &stream->prio_list, prio_sched) {
		if (p->prio == prio)
			return sctp_sched_prio_head_get(p);
		if (p->prio > prio)
			break;
	}

	/* No luck. So we search on all streams now. */
	for (i = 0; i < stream->outcnt; i++) {
		if (!SCTP_SO(stream, i)->ext)
			continue;

		p = SCTP_SO(stream, i)->ext->prio_head;
		if (!p)
			/* Means all other streams won't be initialized
			 * as well.
			 */
			break;
		if (p->prio == prio)
			return sctp_sched_prio_head_get(p);
	}

	/* If not even there, allocate a new one. */
	return sctp_sched_prio_new_head(stream, prio, gfp);
}

static void sctp_sched_prio_next_stream(struct sctp_stream_priorities *p)
{
	struct list_head *pos;

	pos = p->next->prio_list.next;
	if (pos == &p->active)
		pos = pos->next;
	p->next = list_entry(pos, struct sctp_stream_out_ext, prio_list);
}

static bool sctp_sched_prio_unsched(struct sctp_stream_out_ext *soute)
{
	bool scheduled = false;

	if (!list_empty(&soute->prio_list)) {
		struct sctp_stream_priorities *prio_head = soute->prio_head;

		/* Scheduled */
		scheduled = true;

		if (prio_head->next == soute)
			/* Try to move to the next stream */
			sctp_sched_prio_next_stream(prio_head);

		list_del_init(&soute->prio_list);

		/* Also unsched the priority if this was the last stream */
		if (list_empty(&prio_head->active)) {
			list_del_init(&prio_head->prio_sched);
			/* If there is no stream left, clear next */
			prio_head->next = NULL;
		}
	}

	return scheduled;
}

static void sctp_sched_prio_sched(struct sctp_stream *stream,
				  struct sctp_stream_out_ext *soute)
{
	struct sctp_stream_priorities *prio, *prio_head;

	prio_head = soute->prio_head;

	/* Nothing to do if already scheduled */
	if (!list_empty(&soute->prio_list))
		return;

	/* Schedule the stream. If there is a next, we schedule the new
	 * one before it, so it's the last in round robin order.
	 * If there isn't, we also have to schedule the priority.
	 */
	if (prio_head->next) {
		list_add(&soute->prio_list, prio_head->next->prio_list.prev);
		return;
	}

	list_add(&soute->prio_list, &prio_head->active);
	prio_head->next = soute;

	list_for_each_entry(prio, &stream->prio_list, prio_sched) {
		if (prio->prio > prio_head->prio) {
			list_add(&prio_head->prio_sched, prio->prio_sched.prev);
			return;
		}
	}

	list_add_tail(&prio_head->prio_sched, &stream->prio_list);
}

static int sctp_sched_prio_set(struct sctp_stream *stream, __u16 sid,
			       __u16 prio, gfp_t gfp)
{
	struct sctp_stream_out *sout = SCTP_SO(stream, sid);
	struct sctp_stream_out_ext *soute = sout->ext;
	struct sctp_stream_priorities *prio_head, *old;
	bool reschedule = false;

	old = soute->prio_head;
	if (old && old->prio == prio)
		return 0;

	prio_head = sctp_sched_prio_get_head(stream, prio, gfp);
	if (!prio_head)
		return -ENOMEM;

	reschedule = sctp_sched_prio_unsched(soute);
	soute->prio_head = prio_head;
	if (reschedule)
		sctp_sched_prio_sched(stream, soute);

	sctp_sched_prio_head_put(old);
	return 0;
}

static int sctp_sched_prio_get(struct sctp_stream *stream, __u16 sid,
			       __u16 *value)
{
	*value = SCTP_SO(stream, sid)->ext->prio_head->prio;
	return 0;
}

static int sctp_sched_prio_init(struct sctp_stream *stream)
{
	INIT_LIST_HEAD(&stream->prio_list);

	return 0;
}

static int sctp_sched_prio_init_sid(struct sctp_stream *stream, __u16 sid,
				    gfp_t gfp)
{
	INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->prio_list);
	return sctp_sched_prio_set(stream, sid, 0, gfp);
}

static void sctp_sched_prio_free_sid(struct sctp_stream *stream, __u16 sid)
{
	sctp_sched_prio_head_put(SCTP_SO(stream, sid)->ext->prio_head);
	SCTP_SO(stream, sid)->ext->prio_head = NULL;
}

static void sctp_sched_prio_enqueue(struct sctp_outq *q,
				    struct sctp_datamsg *msg)
{
	struct sctp_stream *stream;
	struct sctp_chunk *ch;
	__u16 sid;

	ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
	sid = sctp_chunk_stream_no(ch);
	stream = &q->asoc->stream;
	sctp_sched_prio_sched(stream, SCTP_SO(stream, sid)->ext);
}

static struct sctp_chunk *sctp_sched_prio_dequeue(struct sctp_outq *q)
{
	struct sctp_stream *stream = &q->asoc->stream;
	struct sctp_stream_priorities *prio;
	struct sctp_stream_out_ext *soute;
	struct sctp_chunk *ch = NULL;

	/* Bail out quickly if queue is empty */
	if (list_empty(&q->out_chunk_list))
		goto out;

	/* Find which chunk is next. It's easy, it's either the current
	 * one or the first chunk on the next active stream.
	 */
	if (stream->out_curr) {
		soute = stream->out_curr->ext;
	} else {
		prio = list_entry(stream->prio_list.next,
				  struct sctp_stream_priorities, prio_sched);
		soute = prio->next;
	}
	ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
	sctp_sched_dequeue_common(q, ch);

out:
	return ch;
}

static void sctp_sched_prio_dequeue_done(struct sctp_outq *q,
					 struct sctp_chunk *ch)
{
	struct sctp_stream_priorities *prio;
	struct sctp_stream_out_ext *soute;
	__u16 sid;

	/* Last chunk on that msg, move to the next stream on
	 * this priority.
	 */
	sid = sctp_chunk_stream_no(ch);
	soute = SCTP_SO(&q->asoc->stream, sid)->ext;
	prio = soute->prio_head;

	sctp_sched_prio_next_stream(prio);

	if (list_empty(&soute->outq))
		sctp_sched_prio_unsched(soute);
}

static void sctp_sched_prio_sched_all(struct sctp_stream *stream)
{
	struct sctp_association *asoc;
	struct sctp_stream_out *sout;
	struct sctp_chunk *ch;

	asoc = container_of(stream, struct sctp_association, stream);
	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
		__u16 sid;

		sid = sctp_chunk_stream_no(ch);
		sout = SCTP_SO(stream, sid);
		if (sout->ext)
			sctp_sched_prio_sched(stream, sout->ext);
	}
}

static void sctp_sched_prio_unsched_all(struct sctp_stream *stream)
{
	struct sctp_stream_priorities *p, *tmp;
	struct sctp_stream_out_ext *soute, *souttmp;

	list_for_each_entry_safe(p, tmp, &stream->prio_list, prio_sched)
		list_for_each_entry_safe(soute, souttmp, &p->active, prio_list)
			sctp_sched_prio_unsched(soute);
}

static struct sctp_sched_ops sctp_sched_prio = {
	.set = sctp_sched_prio_set,
	.get = sctp_sched_prio_get,
	.init = sctp_sched_prio_init,
	.init_sid = sctp_sched_prio_init_sid,
	.free_sid = sctp_sched_prio_free_sid,
	.enqueue = sctp_sched_prio_enqueue,
	.dequeue = sctp_sched_prio_dequeue,
	.dequeue_done = sctp_sched_prio_dequeue_done,
	.sched_all = sctp_sched_prio_sched_all,
	.unsched_all = sctp_sched_prio_unsched_all,
};

void sctp_sched_ops_prio_init(void)
{
	sctp_sched_ops_register(SCTP_SS_PRIO, &sctp_sched_prio);
}