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_free(struct sctp_stream *stream) 98 { 99 sctp_sched_rr_unsched_all(stream); 100 } 101 102 static void sctp_sched_rr_enqueue(struct sctp_outq *q, 103 struct sctp_datamsg *msg) 104 { 105 struct sctp_stream *stream; 106 struct sctp_chunk *ch; 107 __u16 sid; 108 109 ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list); 110 sid = sctp_chunk_stream_no(ch); 111 stream = &q->asoc->stream; 112 sctp_sched_rr_sched(stream, SCTP_SO(stream, sid)->ext); 113 } 114 115 static struct sctp_chunk *sctp_sched_rr_dequeue(struct sctp_outq *q) 116 { 117 struct sctp_stream *stream = &q->asoc->stream; 118 struct sctp_stream_out_ext *soute; 119 struct sctp_chunk *ch = NULL; 120 121 /* Bail out quickly if queue is empty */ 122 if (list_empty(&q->out_chunk_list)) 123 goto out; 124 125 /* Find which chunk is next */ 126 if (stream->out_curr) 127 soute = stream->out_curr->ext; 128 else 129 soute = stream->rr_next; 130 ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list); 131 132 sctp_sched_dequeue_common(q, ch); 133 134 out: 135 return ch; 136 } 137 138 static void sctp_sched_rr_dequeue_done(struct sctp_outq *q, 139 struct sctp_chunk *ch) 140 { 141 struct sctp_stream_out_ext *soute; 142 __u16 sid; 143 144 /* Last chunk on that msg, move to the next stream */ 145 sid = sctp_chunk_stream_no(ch); 146 soute = SCTP_SO(&q->asoc->stream, sid)->ext; 147 148 sctp_sched_rr_next_stream(&q->asoc->stream); 149 150 if (list_empty(&soute->outq)) 151 sctp_sched_rr_unsched(&q->asoc->stream, soute); 152 } 153 154 static void sctp_sched_rr_sched_all(struct sctp_stream *stream) 155 { 156 struct sctp_association *asoc; 157 struct sctp_stream_out_ext *soute; 158 struct sctp_chunk *ch; 159 160 asoc = container_of(stream, struct sctp_association, stream); 161 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) { 162 __u16 sid; 163 164 sid = sctp_chunk_stream_no(ch); 165 soute = SCTP_SO(stream, sid)->ext; 166 if (soute) 167 sctp_sched_rr_sched(stream, soute); 168 } 169 } 170 171 static void sctp_sched_rr_unsched_all(struct sctp_stream *stream) 172 { 173 struct sctp_stream_out_ext *soute, *tmp; 174 175 list_for_each_entry_safe(soute, tmp, &stream->rr_list, rr_list) 176 sctp_sched_rr_unsched(stream, soute); 177 } 178 179 static struct sctp_sched_ops sctp_sched_rr = { 180 .set = sctp_sched_rr_set, 181 .get = sctp_sched_rr_get, 182 .init = sctp_sched_rr_init, 183 .init_sid = sctp_sched_rr_init_sid, 184 .free_sid = sctp_sched_rr_free_sid, 185 .free = sctp_sched_rr_free, 186 .enqueue = sctp_sched_rr_enqueue, 187 .dequeue = sctp_sched_rr_dequeue, 188 .dequeue_done = sctp_sched_rr_dequeue_done, 189 .sched_all = sctp_sched_rr_sched_all, 190 .unsched_all = sctp_sched_rr_unsched_all, 191 }; 192 193 void sctp_sched_ops_rr_init(void) 194 { 195 sctp_sched_ops_register(SCTP_SS_RR, &sctp_sched_rr); 196 } 197