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_sid(struct sctp_stream *stream, __u16 sid) 94 { 95 } 96 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 } 109 110 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 } 132 133 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 } 148 149 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 } 165 166 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 }; 186 187 void sctp_sched_ops_rr_init(void) 188 { 189 sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr); 190 } 191