xref: /linux/net/sctp/stream_sched_rr.c (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
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 
sctp_sched_rr_next_stream(struct sctp_stream * stream)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 
sctp_sched_rr_unsched(struct sctp_stream * stream,struct sctp_stream_out_ext * soute)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 
sctp_sched_rr_sched(struct sctp_stream * stream,struct sctp_stream_out_ext * soute)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 
sctp_sched_rr_set(struct sctp_stream * stream,__u16 sid,__u16 prio,gfp_t gfp)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 
sctp_sched_rr_get(struct sctp_stream * stream,__u16 sid,__u16 * value)71 static int sctp_sched_rr_get(struct sctp_stream *stream, __u16 sid,
72 			     __u16 *value)
73 {
74 	return 0;
75 }
76 
sctp_sched_rr_init(struct sctp_stream * stream)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 
sctp_sched_rr_init_sid(struct sctp_stream * stream,__u16 sid,gfp_t gfp)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 
sctp_sched_rr_free_sid(struct sctp_stream * stream,__u16 sid)93 static void sctp_sched_rr_free_sid(struct sctp_stream *stream, __u16 sid)
94 {
95 }
96 
sctp_sched_rr_enqueue(struct sctp_outq * q,struct sctp_datamsg * msg)97 static void sctp_sched_rr_enqueue(struct sctp_outq *q,
98 				  struct sctp_datamsg *msg)
99 {
100 	struct sctp_stream *stream;
101 	struct sctp_chunk *ch;
102 	__u16 sid;
103 
104 	ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
105 	sid = sctp_chunk_stream_no(ch);
106 	stream = &q->asoc->stream;
107 	sctp_sched_rr_sched(stream, SCTP_SO(stream, sid)->ext);
108 }
109 
sctp_sched_rr_dequeue(struct sctp_outq * q)110 static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q)
111 {
112 	struct sctp_stream *stream = &q->asoc->stream;
113 	struct sctp_stream_out_ext *soute;
114 	struct sctp_chunk *ch = NULL;
115 
116 	/* Bail out quickly if queue is empty */
117 	if (list_empty(&q->out_chunk_list))
118 		goto out;
119 
120 	/* Find which chunk is next */
121 	if (stream->out_curr)
122 		soute = stream->out_curr->ext;
123 	else
124 		soute = stream->rr_next;
125 	ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
126 
127 	sctp_sched_dequeue_common(q, ch);
128 
129 out:
130 	return ch;
131 }
132 
sctp_sched_rr_dequeue_done(struct sctp_outq * q,struct sctp_chunk * ch)133 static void sctp_sched_rr_dequeue_done(struct sctp_outq *q,
134 				       struct sctp_chunk *ch)
135 {
136 	struct sctp_stream_out_ext *soute;
137 	__u16 sid;
138 
139 	/* Last chunk on that msg, move to the next stream */
140 	sid = sctp_chunk_stream_no(ch);
141 	soute = SCTP_SO(&q->asoc->stream, sid)->ext;
142 
143 	sctp_sched_rr_next_stream(&q->asoc->stream);
144 
145 	if (list_empty(&soute->outq))
146 		sctp_sched_rr_unsched(&q->asoc->stream, soute);
147 }
148 
sctp_sched_rr_sched_all(struct sctp_stream * stream)149 static void sctp_sched_rr_sched_all(struct sctp_stream *stream)
150 {
151 	struct sctp_association *asoc;
152 	struct sctp_stream_out_ext *soute;
153 	struct sctp_chunk *ch;
154 
155 	asoc = container_of(stream, struct sctp_association, stream);
156 	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
157 		__u16 sid;
158 
159 		sid = sctp_chunk_stream_no(ch);
160 		soute = SCTP_SO(stream, sid)->ext;
161 		if (soute)
162 			sctp_sched_rr_sched(stream, soute);
163 	}
164 }
165 
sctp_sched_rr_unsched_all(struct sctp_stream * stream)166 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream)
167 {
168 	struct sctp_stream_out_ext *soute, *tmp;
169 
170 	list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list)
171 		sctp_sched_rr_unsched(stream, soute);
172 }
173 
174 static struct sctp_sched_ops sctp_sched_rr = {
175 	.set = sctp_sched_rr_set,
176 	.get = sctp_sched_rr_get,
177 	.init = sctp_sched_rr_init,
178 	.init_sid = sctp_sched_rr_init_sid,
179 	.free_sid = sctp_sched_rr_free_sid,
180 	.enqueue = sctp_sched_rr_enqueue,
181 	.dequeue = sctp_sched_rr_dequeue,
182 	.dequeue_done = sctp_sched_rr_dequeue_done,
183 	.sched_all = sctp_sched_rr_sched_all,
184 	.unsched_all = sctp_sched_rr_unsched_all,
185 };
186 
sctp_sched_ops_rr_init(void)187 void sctp_sched_ops_rr_init(void)
188 {
189 	sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr);
190 }
191