MEDIUM: mux-h2: merge recv_wait and send_wait event notifications

This is the continuation of the recv+send event notifications merge
that was started. This patch is less trivial than the previous ones
because the existence of a send event subscription is also used to
decide to put a stream back into the send list.

diff --git a/src/mux_h2.c b/src/mux_h2.c
index c4edd406164127116eb77c73f730dd02399e4f47..5a1b22672fbd8da14055785aed44c1f0c94d5b01 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -206,8 +206,7 @@ struct h2s {
        uint16_t status;     /* HTTP response status */
        unsigned long long body_len; /* remaining body length according to content-length if H2_SF_DATA_CLEN */
        struct buffer rxbuf; /* receive buffer, always valid (buf_empty or real buffer) */
-       struct wait_event *recv_wait; /* recv wait_event the conn_stream associated is waiting on (via h2_subscribe) */
-       struct wait_event *send_wait; /* send wait_event the conn_stream associated is waiting on (via h2_subscribe) */
+       struct wait_event *subs;      /* recv wait_event the conn_stream associated is waiting on (via h2_subscribe) */
        struct list list; /* To be used when adding in h2c->send_list or h2c->fctl_lsit */
        struct tasklet *shut_tl;  /* deferred shutdown tasklet, to retry to send an RST after we failed to,
                                   * in case there's no other subscription to do it */
@@ -1037,29 +1036,25 @@ static inline __maybe_unused void h2s_error(struct h2s *h2s, enum h2_err err)
 /* attempt to notify the data layer of recv availability */
 static void __maybe_unused h2s_notify_recv(struct h2s *h2s)
 {
-       struct wait_event *sw;
-
-       if (h2s->recv_wait) {
+       if (h2s->subs && h2s->subs->events & SUB_RETRY_RECV) {
                TRACE_POINT(H2_EV_STRM_WAKE, h2s->h2c->conn, h2s);
-               sw = h2s->recv_wait;
-               sw->events &= ~SUB_RETRY_RECV;
-               tasklet_wakeup(sw->tasklet);
-               h2s->recv_wait = NULL;
+               tasklet_wakeup(h2s->subs->tasklet);
+               h2s->subs->events &= ~SUB_RETRY_RECV;
+               if (!h2s->subs->events)
+                       h2s->subs = NULL;
        }
 }
 
 /* attempt to notify the data layer of send availability */
 static void __maybe_unused h2s_notify_send(struct h2s *h2s)
 {
-       struct wait_event *sw;
-
-       if (h2s->send_wait) {
+       if (h2s->subs && h2s->subs->events & SUB_RETRY_SEND) {
                TRACE_POINT(H2_EV_STRM_WAKE, h2s->h2c->conn, h2s);
-               sw = h2s->send_wait;
-               h2s->send_wait = NULL;
-               sw->events &= ~SUB_RETRY_SEND;
                h2s->flags |= H2_SF_NOTIFIED;
-               tasklet_wakeup(sw->tasklet);
+               tasklet_wakeup(h2s->subs->tasklet);
+               h2s->subs->events &= ~SUB_RETRY_SEND;
+               if (!h2s->subs->events)
+                       h2s->subs = NULL;
        }
        else if (h2s->flags & (H2_SF_WANT_SHUTR | H2_SF_WANT_SHUTW)) {
                TRACE_POINT(H2_EV_STRM_WAKE, h2s->h2c->conn, h2s);
@@ -1079,7 +1074,7 @@ static void __maybe_unused h2s_alert(struct h2s *h2s)
 {
        TRACE_ENTER(H2_EV_H2S_WAKE, h2s->h2c->conn, h2s);
 
-       if (h2s->recv_wait || h2s->send_wait ||
+       if (h2s->subs ||
            (h2s->flags & (H2_SF_WANT_SHUTR | H2_SF_WANT_SHUTW))) {
                h2s_notify_recv(h2s);
                h2s_notify_send(h2s);
@@ -1266,10 +1261,10 @@ static void h2s_destroy(struct h2s *h2s)
                b_free(&h2s->rxbuf);
                offer_buffers(NULL, tasks_run_queue);
        }
-       if (h2s->send_wait != NULL)
-               h2s->send_wait->events &= ~SUB_RETRY_SEND;
-       if (h2s->recv_wait != NULL)
-               h2s->recv_wait->events &= ~SUB_RETRY_RECV;
+
+       if (h2s->subs)
+               h2s->subs->events = 0;
+
        /* There's no need to explicitly call unsubscribe here, the only
         * reference left would be in the h2c send_list/fctl_list, and if
         * we're in it, we're getting out anyway
@@ -1304,8 +1299,7 @@ static struct h2s *h2s_new(struct h2c *h2c, int id)
                pool_free(pool_head_h2s, h2s);
                goto out;
        }
-       h2s->send_wait = NULL;
-       h2s->recv_wait = NULL;
+       h2s->subs = NULL;
        h2s->shut_tl->process = h2_deferred_shut;
        h2s->shut_tl->context = h2s;
        LIST_INIT(&h2s->list);
@@ -1982,7 +1976,8 @@ static void h2c_unblock_sfctl(struct h2c *h2c)
                if (h2s->flags & H2_SF_BLK_SFCTL && h2s_mws(h2s) > 0) {
                        h2s->flags &= ~H2_SF_BLK_SFCTL;
                        LIST_DEL_INIT(&h2s->list);
-                       if (h2s->send_wait || h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW))
+                       if ((h2s->subs && h2s->subs->events & SUB_RETRY_SEND) ||
+                           h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW))
                                LIST_ADDQ(&h2c->send_list, &h2s->list);
                }
                node = eb32_next(node);
@@ -2322,7 +2317,8 @@ static int h2c_handle_window_update(struct h2c *h2c, struct h2s *h2s)
                if (h2s_mws(h2s) > 0 && (h2s->flags & H2_SF_BLK_SFCTL)) {
                        h2s->flags &= ~H2_SF_BLK_SFCTL;
                        LIST_DEL_INIT(&h2s->list);
-                       if (h2s->send_wait || h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW))
+                       if ((h2s->subs && h2s->subs->events & SUB_RETRY_SEND) ||
+                           h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW))
                                LIST_ADDQ(&h2c->send_list, &h2s->list);
                }
        }
@@ -3263,17 +3259,18 @@ static void h2_resume_each_sending_h2s(struct h2c *h2c, struct list *head)
                /* If the sender changed his mind and unsubscribed, let's just
                 * remove the stream from the send_list.
                 */
-               if (!h2s->send_wait &&
-                   !(h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW))) {
+               if (!(h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW)) &&
+                   (!h2s->subs || !(h2s->subs->events & SUB_RETRY_SEND))) {
                        LIST_DEL_INIT(&h2s->list);
                        continue;
                }
 
-               if (h2s->send_wait) {
-                       h2s->send_wait->events &= ~SUB_RETRY_SEND;
+               if (h2s->subs && h2s->subs->events & SUB_RETRY_SEND) {
                        h2s->flags |= H2_SF_NOTIFIED;
-                       tasklet_wakeup(h2s->send_wait->tasklet);
-                       h2s->send_wait = NULL;
+                       tasklet_wakeup(h2s->subs->tasklet);
+                       h2s->subs->events &= ~SUB_RETRY_SEND;
+                       if (!h2s->subs->events)
+                               h2s->subs = NULL;
                }
                else if (h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW)) {
                        tasklet_wakeup(h2s->shut_tl);
@@ -3861,7 +3858,7 @@ static void h2_detach(struct conn_stream *cs)
        if (!(cs->conn->flags & CO_FL_ERROR) &&
            (h2c->st0 < H2_CS_ERROR) &&
            (h2s->flags & (H2_SF_BLK_MBUSY | H2_SF_BLK_MROOM | H2_SF_BLK_MFCTL)) &&
-           ((h2s->flags & (H2_SF_WANT_SHUTR | H2_SF_WANT_SHUTW)) || h2s->send_wait || h2s->recv_wait)) {
+           ((h2s->flags & (H2_SF_WANT_SHUTR | H2_SF_WANT_SHUTW)) || h2s->subs)) {
                TRACE_DEVEL("leaving on stream blocked", H2_EV_STRM_END|H2_EV_H2S_BLK, h2c->conn, h2s);
                return;
        }
@@ -5594,32 +5591,30 @@ static size_t h2s_make_trailers(struct h2s *h2s, struct htx *htx)
 
 /* Called from the upper layer, to subscribe to events, such as being able to send.
  * The <param> argument here is supposed to be a pointer to a wait_event struct
- * which will be passed to h2s->recv_wait or h2s->send_wait depending on the
- * event_type. The event_type must only be a combination of SUB_RETRY_RECV and
- * SUB_RETRY_SEND, other values will lead to -1 being returned. It always
- * returns 0 except for the error above.
+ * which will be passed to h2s->subs. The event_type must only be a
+ * combination of SUB_RETRY_RECV and SUB_RETRY_SEND, other values will lead to -1
+ * being returned. It always returns 0 except for the error above.
  */
 static int h2_subscribe(struct conn_stream *cs, int event_type, void *param)
 {
-       struct wait_event *sw;
+       struct wait_event *sw = param;
        struct h2s *h2s = cs->ctx;
        struct h2c *h2c = h2s->h2c;
 
        TRACE_ENTER(H2_EV_STRM_SEND|H2_EV_STRM_RECV, h2c->conn, h2s);
-       if (event_type & SUB_RETRY_RECV) {
+
+       BUG_ON(event_type & ~(SUB_RETRY_SEND|SUB_RETRY_RECV));
+       BUG_ON(h2s->subs && h2s->subs->events & event_type);
+       BUG_ON(h2s->subs && h2s->subs != sw);
+
+       sw->events |= event_type;
+       h2s->subs = sw;
+
+       if (event_type & SUB_RETRY_RECV)
                TRACE_DEVEL("subscribe(recv)", H2_EV_STRM_RECV, h2c->conn, h2s);
-               sw = param;
-               BUG_ON(h2s->recv_wait != NULL || (sw->events & SUB_RETRY_RECV));
-               sw->events |= SUB_RETRY_RECV;
-               h2s->recv_wait = sw;
-               event_type &= ~SUB_RETRY_RECV;
-       }
+
        if (event_type & SUB_RETRY_SEND) {
                TRACE_DEVEL("subscribe(send)", H2_EV_STRM_SEND, h2c->conn, h2s);
-               sw = param;
-               BUG_ON(h2s->send_wait != NULL || (sw->events & SUB_RETRY_SEND));
-               sw->events |= SUB_RETRY_SEND;
-               h2s->send_wait = sw;
                if (!(h2s->flags & H2_SF_BLK_SFCTL) &&
                    !LIST_ADDED(&h2s->list)) {
                        if (h2s->flags & H2_SF_BLK_MFCTL)
@@ -5627,11 +5622,8 @@ static int h2_subscribe(struct conn_stream *cs, int event_type, void *param)
                        else
                                LIST_ADDQ(&h2c->send_list, &h2s->list);
                }
-               event_type &= ~SUB_RETRY_SEND;
        }
        TRACE_LEAVE(H2_EV_STRM_SEND|H2_EV_STRM_RECV, h2c->conn, h2s);
-       if (event_type != 0)
-               return -1;
        return 0;
 }
 
@@ -5642,28 +5634,28 @@ static int h2_subscribe(struct conn_stream *cs, int event_type, void *param)
  */
 static int h2_unsubscribe(struct conn_stream *cs, int event_type, void *param)
 {
-       struct wait_event *sw;
+       struct wait_event *sw = param;
        struct h2s *h2s = cs->ctx;
 
        TRACE_ENTER(H2_EV_STRM_SEND|H2_EV_STRM_RECV, h2s->h2c->conn, h2s);
-       if (event_type & SUB_RETRY_RECV) {
+
+       BUG_ON(event_type & ~(SUB_RETRY_SEND|SUB_RETRY_RECV));
+       BUG_ON(h2s->subs && h2s->subs != sw);
+
+       sw->events &= ~event_type;
+       if (!sw->events)
+               h2s->subs = NULL;
+
+       if (event_type & SUB_RETRY_RECV)
                TRACE_DEVEL("unsubscribe(recv)", H2_EV_STRM_RECV, h2s->h2c->conn, h2s);
-               sw = param;
-               BUG_ON(h2s->recv_wait != sw);
-               sw->events &= ~SUB_RETRY_RECV;
-               h2s->recv_wait = NULL;
-       }
 
        if (event_type & SUB_RETRY_SEND) {
                TRACE_DEVEL("subscribe(send)", H2_EV_STRM_SEND, h2s->h2c->conn, h2s);
-               sw = param;
-               BUG_ON(h2s->send_wait != sw);
-               if (!(h2s->flags & (H2_SF_WANT_SHUTR|H2_SF_WANT_SHUTW)))
-                       LIST_DEL_INIT(&h2s->list);
-               sw->events &= ~SUB_RETRY_SEND;
                h2s->flags &= ~H2_SF_NOTIFIED;
-               h2s->send_wait = NULL;
+               if (!(h2s->flags & (H2_SF_WANT_SHUTR | H2_SF_WANT_SHUTW)))
+                       LIST_DEL_INIT(&h2s->list);
        }
+
        TRACE_LEAVE(H2_EV_STRM_SEND|H2_EV_STRM_RECV, h2s->h2c->conn, h2s);
        return 0;
 }