treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104
[sfrench/cifs-2.6.git] / net / sctp / stream_sched.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright Red Hat Inc. 2017
4  *
5  * This file is part of the SCTP kernel implementation
6  *
7  * These functions manipulate sctp stream queue/scheduling.
8  *
9  * Please send any bug reports or fixes you make to the
10  * email addresched(es):
11  *    lksctp developers <linux-sctp@vger.kernel.org>
12  *
13  * Written or modified by:
14  *    Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
15  */
16
17 #include <linux/list.h>
18 #include <net/sctp/sctp.h>
19 #include <net/sctp/sm.h>
20 #include <net/sctp/stream_sched.h>
21
22 /* First Come First Serve (a.k.a. FIFO)
23  * RFC DRAFT ndata Section 3.1
24  */
25 static int sctp_sched_fcfs_set(struct sctp_stream *stream, __u16 sid,
26                                __u16 value, gfp_t gfp)
27 {
28         return 0;
29 }
30
31 static int sctp_sched_fcfs_get(struct sctp_stream *stream, __u16 sid,
32                                __u16 *value)
33 {
34         *value = 0;
35         return 0;
36 }
37
38 static int sctp_sched_fcfs_init(struct sctp_stream *stream)
39 {
40         return 0;
41 }
42
43 static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
44                                     gfp_t gfp)
45 {
46         return 0;
47 }
48
49 static void sctp_sched_fcfs_free(struct sctp_stream *stream)
50 {
51 }
52
53 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
54                                     struct sctp_datamsg *msg)
55 {
56 }
57
58 static struct sctp_chunk *sctp_sched_fcfs_dequeue(struct sctp_outq *q)
59 {
60         struct sctp_stream *stream = &q->asoc->stream;
61         struct sctp_chunk *ch = NULL;
62         struct list_head *entry;
63
64         if (list_empty(&q->out_chunk_list))
65                 goto out;
66
67         if (stream->out_curr) {
68                 ch = list_entry(stream->out_curr->ext->outq.next,
69                                 struct sctp_chunk, stream_list);
70         } else {
71                 entry = q->out_chunk_list.next;
72                 ch = list_entry(entry, struct sctp_chunk, list);
73         }
74
75         sctp_sched_dequeue_common(q, ch);
76
77 out:
78         return ch;
79 }
80
81 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
82                                          struct sctp_chunk *chunk)
83 {
84 }
85
86 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
87 {
88 }
89
90 static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
91 {
92 }
93
94 static struct sctp_sched_ops sctp_sched_fcfs = {
95         .set = sctp_sched_fcfs_set,
96         .get = sctp_sched_fcfs_get,
97         .init = sctp_sched_fcfs_init,
98         .init_sid = sctp_sched_fcfs_init_sid,
99         .free = sctp_sched_fcfs_free,
100         .enqueue = sctp_sched_fcfs_enqueue,
101         .dequeue = sctp_sched_fcfs_dequeue,
102         .dequeue_done = sctp_sched_fcfs_dequeue_done,
103         .sched_all = sctp_sched_fcfs_sched_all,
104         .unsched_all = sctp_sched_fcfs_unsched_all,
105 };
106
107 static void sctp_sched_ops_fcfs_init(void)
108 {
109         sctp_sched_ops_register(SCTP_SS_FCFS, &sctp_sched_fcfs);
110 }
111
112 /* API to other parts of the stack */
113
114 static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
115
116 void sctp_sched_ops_register(enum sctp_sched_type sched,
117                              struct sctp_sched_ops *sched_ops)
118 {
119         sctp_sched_ops[sched] = sched_ops;
120 }
121
122 void sctp_sched_ops_init(void)
123 {
124         sctp_sched_ops_fcfs_init();
125         sctp_sched_ops_prio_init();
126         sctp_sched_ops_rr_init();
127 }
128
129 int sctp_sched_set_sched(struct sctp_association *asoc,
130                          enum sctp_sched_type sched)
131 {
132         struct sctp_sched_ops *n = sctp_sched_ops[sched];
133         struct sctp_sched_ops *old = asoc->outqueue.sched;
134         struct sctp_datamsg *msg = NULL;
135         struct sctp_chunk *ch;
136         int i, ret = 0;
137
138         if (old == n)
139                 return ret;
140
141         if (sched > SCTP_SS_MAX)
142                 return -EINVAL;
143
144         if (old) {
145                 old->free(&asoc->stream);
146
147                 /* Give the next scheduler a clean slate. */
148                 for (i = 0; i < asoc->stream.outcnt; i++) {
149                         void *p = SCTP_SO(&asoc->stream, i)->ext;
150
151                         if (!p)
152                                 continue;
153
154                         p += offsetofend(struct sctp_stream_out_ext, outq);
155                         memset(p, 0, sizeof(struct sctp_stream_out_ext) -
156                                      offsetofend(struct sctp_stream_out_ext, outq));
157                 }
158         }
159
160         asoc->outqueue.sched = n;
161         n->init(&asoc->stream);
162         for (i = 0; i < asoc->stream.outcnt; i++) {
163                 if (!SCTP_SO(&asoc->stream, i)->ext)
164                         continue;
165
166                 ret = n->init_sid(&asoc->stream, i, GFP_KERNEL);
167                 if (ret)
168                         goto err;
169         }
170
171         /* We have to requeue all chunks already queued. */
172         list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
173                 if (ch->msg == msg)
174                         continue;
175                 msg = ch->msg;
176                 n->enqueue(&asoc->outqueue, msg);
177         }
178
179         return ret;
180
181 err:
182         n->free(&asoc->stream);
183         asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
184
185         return ret;
186 }
187
188 int sctp_sched_get_sched(struct sctp_association *asoc)
189 {
190         int i;
191
192         for (i = 0; i <= SCTP_SS_MAX; i++)
193                 if (asoc->outqueue.sched == sctp_sched_ops[i])
194                         return i;
195
196         return 0;
197 }
198
199 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
200                          __u16 value, gfp_t gfp)
201 {
202         if (sid >= asoc->stream.outcnt)
203                 return -EINVAL;
204
205         if (!SCTP_SO(&asoc->stream, sid)->ext) {
206                 int ret;
207
208                 ret = sctp_stream_init_ext(&asoc->stream, sid);
209                 if (ret)
210                         return ret;
211         }
212
213         return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
214 }
215
216 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
217                          __u16 *value)
218 {
219         if (sid >= asoc->stream.outcnt)
220                 return -EINVAL;
221
222         if (!SCTP_SO(&asoc->stream, sid)->ext)
223                 return 0;
224
225         return asoc->outqueue.sched->get(&asoc->stream, sid, value);
226 }
227
228 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
229 {
230         if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
231             !q->asoc->intl_enable) {
232                 struct sctp_stream_out *sout;
233                 __u16 sid;
234
235                 /* datamsg is not finish, so save it as current one,
236                  * in case application switch scheduler or a higher
237                  * priority stream comes in.
238                  */
239                 sid = sctp_chunk_stream_no(ch);
240                 sout = SCTP_SO(&q->asoc->stream, sid);
241                 q->asoc->stream.out_curr = sout;
242                 return;
243         }
244
245         q->asoc->stream.out_curr = NULL;
246         q->sched->dequeue_done(q, ch);
247 }
248
249 /* Auxiliary functions for the schedulers */
250 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
251 {
252         list_del_init(&ch->list);
253         list_del_init(&ch->stream_list);
254         q->out_qlen -= ch->skb->len;
255 }
256
257 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
258 {
259         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
260         struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
261
262         INIT_LIST_HEAD(&ext->outq);
263         return sched->init_sid(stream, sid, gfp);
264 }
265
266 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
267 {
268         struct sctp_association *asoc;
269
270         asoc = container_of(stream, struct sctp_association, stream);
271
272         return asoc->outqueue.sched;
273 }