net/sctp/stream_sched_prio.c - third_party/linux - Git at Google

 /* 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.
  *
  * This SCTP implementation is free software;
  * you can redistribute it and/or modify it under the terms of
  * the GNU General Public License as published by
  * the Free Software Foundation; either version 2, or (at your option)
  * any later version.
  *
  * This SCTP implementation is distributed in the hope that it
  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  *                 ************************
  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  * See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with GNU CC; see the file COPYING.  If not, see
  * <http://www.gnu.org/licenses/>.
  *
  * 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 (!stream->out[i].ext)
 			continue;

 		p = stream->out[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 = &stream->out[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 = stream->out[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 = stream->out[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(&stream->out[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 (!stream->out[i].ext)
 			continue;
 		prio = stream->out[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, stream->out[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 = q->asoc->stream.out[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 = &stream->out[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);
 }
	/* 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.
	*
	* This SCTP implementation is free software;
	* you can redistribute it and/or modify it under the terms of
	* the GNU General Public License as published by
	* the Free Software Foundation; either version 2, or (at your option)
	* any later version.
	*
	* This SCTP implementation is distributed in the hope that it
	* will be useful, but WITHOUT ANY WARRANTY; without even the implied
	* ************************
	* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	* See the GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with GNU CC; see the file COPYING. If not, see
	* <http://www.gnu.org/licenses/>.
	*
	* 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 (!stream->out[i].ext)
	continue;

	p = stream->out[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 = &stream->out[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 = stream->out[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 = stream->out[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(&stream->out[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 (!stream->out[i].ext)
	continue;
	prio = stream->out[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, stream->out[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 = q->asoc->stream.out[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 = &stream->out[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);
	}