// SPDX-License-Identifier: GPL-2.0-or-later /* SCTP kernel implementation * (C) Copyright Red Hat Inc. 2017 * * This file is part of the SCTP kernel implementation * * These functions manipulate sctp stream queue/scheduling. * * Please send any bug reports or fixes you make to the * email addresched(es): * lksctp developers <linux-sctp@vger.kernel.org> * * Written or modified by: * Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> */ #include <linux/list.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> #include <net/sctp/stream_sched.h> /* Priority handling * RFC DRAFT ndata section 3.4 */ static void sctp_sched_prio_unsched_all(struct sctp_stream *stream); static struct sctp_stream_priorities *sctp_sched_prio_new_head( struct sctp_stream *stream, int prio, gfp_t gfp) { struct sctp_stream_priorities *p; p = kmalloc(sizeof(*p), gfp); if (!p) return NULL; INIT_LIST_HEAD(&p->prio_sched); INIT_LIST_HEAD(&p->active); p->next = NULL; p->prio = prio; return p; } static struct sctp_stream_priorities *sctp_sched_prio_get_head( struct sctp_stream *stream, int prio, gfp_t gfp) { struct sctp_stream_priorities *p; int i; /* Look into scheduled priorities first, as they are sorted and * we can find it fast IF it's scheduled. */ list_for_each_entry(p, &stream->prio_list, prio_sched) { if (p->prio == prio) return p; if (p->prio > prio) break; } /* No luck. So we search on all streams now. */ for (i = 0; i < stream->outcnt; i++) { if (!SCTP_SO(stream, i)->ext) continue; p = SCTP_SO(stream, i)->ext->prio_head; if (!p) /* Means all other streams won't be initialized * as well. */ break; if (p->prio == prio) return p; } /* If not even there, allocate a new one. */ return sctp_sched_prio_new_head(stream, prio, gfp); } static void sctp_sched_prio_next_stream(struct sctp_stream_priorities *p) { struct list_head *pos; pos = p->next->prio_list.next; if (pos == &p->active) pos = pos->next; p->next = list_entry(pos, struct sctp_stream_out_ext, prio_list); } static bool sctp_sched_prio_unsched(struct sctp_stream_out_ext *soute) { bool scheduled = false; if (!list_empty(&soute->prio_list)) { struct sctp_stream_priorities *prio_head = soute->prio_head; /* Scheduled */ scheduled = true; if (prio_head->next == soute) /* Try to move to the next stream */ sctp_sched_prio_next_stream(prio_head); list_del_init(&soute->prio_list); /* Also unsched the priority if this was the last stream */ if (list_empty(&prio_head->active)) { list_del_init(&prio_head->prio_sched); /* If there is no stream left, clear next */ prio_head->next = NULL; } } return scheduled; } static void sctp_sched_prio_sched(struct sctp_stream *stream, struct sctp_stream_out_ext *soute) { struct sctp_stream_priorities *prio, *prio_head; prio_head = soute->prio_head; /* Nothing to do if already scheduled */ if (!list_empty(&soute->prio_list)) return; /* Schedule the stream. If there is a next, we schedule the new * one before it, so it's the last in round robin order. * If there isn't, we also have to schedule the priority. */ if (prio_head->next) { list_add(&soute->prio_list, prio_head->next->prio_list.prev); return; } list_add(&soute->prio_list, &prio_head->active); prio_head->next = soute; list_for_each_entry(prio, &stream->prio_list, prio_sched) { if (prio->prio > prio_head->prio) { list_add(&prio_head->prio_sched, prio->prio_sched.prev); return; } } list_add_tail(&prio_head->prio_sched, &stream->prio_list); } static int sctp_sched_prio_set(struct sctp_stream *stream, __u16 sid, __u16 prio, gfp_t gfp) { struct sctp_stream_out *sout = SCTP_SO(stream, sid); struct sctp_stream_out_ext *soute = sout->ext; struct sctp_stream_priorities *prio_head, *old; bool reschedule = false; int i; prio_head = sctp_sched_prio_get_head(stream, prio, gfp); if (!prio_head) return -ENOMEM; reschedule = sctp_sched_prio_unsched(soute); old = soute->prio_head; soute->prio_head = prio_head; if (reschedule) sctp_sched_prio_sched(stream, soute); if (!old) /* Happens when we set the priority for the first time */ return 0; for (i = 0; i < stream->outcnt; i++) { soute = SCTP_SO(stream, i)->ext; if (soute && soute->prio_head == old) /* It's still in use, nothing else to do here. */ return 0; } /* No hits, we are good to free it. */ kfree(old); return 0; } static int sctp_sched_prio_get(struct sctp_stream *stream, __u16 sid, __u16 *value) { *value = SCTP_SO(stream, sid)->ext->prio_head->prio; return 0; } static int sctp_sched_prio_init(struct sctp_stream *stream) { INIT_LIST_HEAD(&stream->prio_list); return 0; } static int sctp_sched_prio_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp) { INIT_LIST_HEAD(&SCTP_SO(stream, sid)->ext->prio_list); return sctp_sched_prio_set(stream, sid, 0, gfp); } static void sctp_sched_prio_free(struct sctp_stream *stream) { struct sctp_stream_priorities *prio, *n; LIST_HEAD(list); int i; /* As we don't keep a list of priorities, to avoid multiple * frees we have to do it in 3 steps: * 1. unsched everyone, so the lists are free to use in 2. * 2. build the list of the priorities * 3. free the list */ sctp_sched_prio_unsched_all(stream); for (i = 0; i < stream->outcnt; i++) { if (!SCTP_SO(stream, i)->ext) continue; prio = SCTP_SO(stream, i)->ext->prio_head; if (prio && list_empty(&prio->prio_sched)) list_add(&prio->prio_sched, &list); } list_for_each_entry_safe(prio, n, &list, prio_sched) { list_del_init(&prio->prio_sched); kfree(prio); } } static void sctp_sched_prio_enqueue(struct sctp_outq *q, struct sctp_datamsg *msg) { struct sctp_stream *stream; struct sctp_chunk *ch; __u16 sid; ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list); sid = sctp_chunk_stream_no(ch); stream = &q->asoc->stream; sctp_sched_prio_sched(stream, SCTP_SO(stream, sid)->ext); } static struct sctp_chunk *sctp_sched_prio_dequeue(struct sctp_outq *q) { struct sctp_stream *stream = &q->asoc->stream; struct sctp_stream_priorities *prio; struct sctp_stream_out_ext *soute; struct sctp_chunk *ch = NULL; /* Bail out quickly if queue is empty */ if (list_empty(&q->out_chunk_list)) goto out; /* Find which chunk is next. It's easy, it's either the current * one or the first chunk on the next active stream. */ if (stream->out_curr) { soute = stream->out_curr->ext; } else { prio = list_entry(stream->prio_list.next, struct sctp_stream_priorities, prio_sched); soute = prio->next; } ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list); sctp_sched_dequeue_common(q, ch); out: return ch; } static void sctp_sched_prio_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch) { struct sctp_stream_priorities *prio; struct sctp_stream_out_ext *soute; __u16 sid; /* Last chunk on that msg, move to the next stream on * this priority. */ sid = sctp_chunk_stream_no(ch); soute = SCTP_SO(&q->asoc->stream, sid)->ext; prio = soute->prio_head; sctp_sched_prio_next_stream(prio); if (list_empty(&soute->outq)) sctp_sched_prio_unsched(soute); } static void sctp_sched_prio_sched_all(struct sctp_stream *stream) { struct sctp_association *asoc; struct sctp_stream_out *sout; struct sctp_chunk *ch; asoc = container_of(stream, struct sctp_association, stream); list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) { __u16 sid; sid = sctp_chunk_stream_no(ch); sout = SCTP_SO(stream, sid); if (sout->ext) sctp_sched_prio_sched(stream, sout->ext); } } static void sctp_sched_prio_unsched_all(struct sctp_stream *stream) { struct sctp_stream_priorities *p, *tmp; struct sctp_stream_out_ext *soute, *souttmp; list_for_each_entry_safe(p, tmp, &stream->prio_list, prio_sched) list_for_each_entry_safe(soute, souttmp, &p->active, prio_list) sctp_sched_prio_unsched(soute); } static struct sctp_sched_ops sctp_sched_prio = { .set = sctp_sched_prio_set, .get = sctp_sched_prio_get, .init = sctp_sched_prio_init, .init_sid = sctp_sched_prio_init_sid, .free = sctp_sched_prio_free, .enqueue = sctp_sched_prio_enqueue, .dequeue = sctp_sched_prio_dequeue, .dequeue_done = sctp_sched_prio_dequeue_done, .sched_all = sctp_sched_prio_sched_all, .unsched_all = sctp_sched_prio_unsched_all, }; void sctp_sched_ops_prio_init(void) { sctp_sched_ops_register(SCTP_SS_PRIO, &sctp_sched_prio); }