Merge tag 'arc-5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[sfrench/cifs-2.6.git] / net / sctp / stream_sched_rr.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 /* Priority handling
23  * RFC DRAFT ndata section 3.2
24  */
25 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream);
26
27 static void sctp_sched_rr_next_stream(struct sctp_stream *stream)
28 {
29         struct list_head *pos;
30
31         pos = stream->rr_next->rr_list.next;
32         if (pos == &stream->rr_list)
33                 pos = pos->next;
34         stream->rr_next = list_entry(pos, struct sctp_stream_out_ext, rr_list);
35 }
36
37 static void sctp_sched_rr_unsched(struct sctp_stream *stream,
38                                   struct sctp_stream_out_ext *soute)
39 {
40         if (stream->rr_next == soute)
41                 /* Try to move to the next stream */
42                 sctp_sched_rr_next_stream(stream);
43
44         list_del_init(&soute->rr_list);
45
46         /* If we have no other stream queued, clear next */
47         if (list_empty(&stream->rr_list))
48                 stream->rr_next = NULL;
49 }
50
51 static void sctp_sched_rr_sched(struct sctp_stream *stream,
52                                 struct sctp_stream_out_ext *soute)
53 {
54         if (!list_empty(&soute->rr_list))
55                 /* Already scheduled. */
56                 return;
57
58         /* Schedule the stream */
59         list_add_tail(&soute->rr_list, &stream->rr_list);
60
61         if (!stream->rr_next)
62                 stream->rr_next = soute;
63 }
64
65 static int sctp_sched_rr_set(struct sctp_stream *stream, __u16 sid,
66                              __u16 prio, gfp_t gfp)
67 {
68         return 0;
69 }
70
71 static int sctp_sched_rr_get(struct sctp_stream *stream, __u16 sid,
72                              __u16 *value)
73 {
74         return 0;
75 }
76
77 static int sctp_sched_rr_init(struct sctp_stream *stream)
78 {
79         INIT_LIST_HEAD(&stream->rr_list);
80         stream->rr_next = NULL;
81
82         return 0;
83 }
84
85 static int sctp_sched_rr_init_sid(struct sctp_stream *stream, __u16 sid,
86                                   gfp_t gfp)
87 {
88         INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->rr_list);
89
90         return 0;
91 }
92
93 static void sctp_sched_rr_free(struct sctp_stream *stream)
94 {
95         sctp_sched_rr_unsched_all(stream);
96 }
97
98 static void sctp_sched_rr_enqueue(struct sctp_outq *q,
99                                   struct sctp_datamsg *msg)
100 {
101         struct sctp_stream *stream;
102         struct sctp_chunk *ch;
103         __u16 sid;
104
105         ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
106         sid = sctp_chunk_stream_no(ch);
107         stream = &q->asoc->stream;
108         sctp_sched_rr_sched(stream, SCTP_SO(stream, sid)->ext);
109 }
110
111 static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q)
112 {
113         struct sctp_stream *stream = &q->asoc->stream;
114         struct sctp_stream_out_ext *soute;
115         struct sctp_chunk *ch = NULL;
116
117         /* Bail out quickly if queue is empty */
118         if (list_empty(&q->out_chunk_list))
119                 goto out;
120
121         /* Find which chunk is next */
122         if (stream->out_curr)
123                 soute = stream->out_curr->ext;
124         else
125                 soute = stream->rr_next;
126         ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
127
128         sctp_sched_dequeue_common(q, ch);
129
130 out:
131         return ch;
132 }
133
134 static void sctp_sched_rr_dequeue_done(struct sctp_outq *q,
135                                        struct sctp_chunk *ch)
136 {
137         struct sctp_stream_out_ext *soute;
138         __u16 sid;
139
140         /* Last chunk on that msg, move to the next stream */
141         sid = sctp_chunk_stream_no(ch);
142         soute = SCTP_SO(&q->asoc->stream, sid)->ext;
143
144         sctp_sched_rr_next_stream(&q->asoc->stream);
145
146         if (list_empty(&soute->outq))
147                 sctp_sched_rr_unsched(&q->asoc->stream, soute);
148 }
149
150 static void sctp_sched_rr_sched_all(struct sctp_stream *stream)
151 {
152         struct sctp_association *asoc;
153         struct sctp_stream_out_ext *soute;
154         struct sctp_chunk *ch;
155
156         asoc = container_of(stream, struct sctp_association, stream);
157         list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
158                 __u16 sid;
159
160                 sid = sctp_chunk_stream_no(ch);
161                 soute = SCTP_SO(stream, sid)->ext;
162                 if (soute)
163                         sctp_sched_rr_sched(stream, soute);
164         }
165 }
166
167 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream)
168 {
169         struct sctp_stream_out_ext *soute, *tmp;
170
171         list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list)
172                 sctp_sched_rr_unsched(stream, soute);
173 }
174
175 static struct sctp_sched_ops sctp_sched_rr = {
176         .set = sctp_sched_rr_set,
177         .get = sctp_sched_rr_get,
178         .init = sctp_sched_rr_init,
179         .init_sid = sctp_sched_rr_init_sid,
180         .free = sctp_sched_rr_free,
181         .enqueue = sctp_sched_rr_enqueue,
182         .dequeue = sctp_sched_rr_dequeue,
183         .dequeue_done = sctp_sched_rr_dequeue_done,
184         .sched_all = sctp_sched_rr_sched_all,
185         .unsched_all = sctp_sched_rr_unsched_all,
186 };
187
188 void sctp_sched_ops_rr_init(void)
189 {
190         sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr);
191 }