MINOR: mux-h1: Add a flag to disable reads on the connection

H1C_F_DONT_READ must be set on the H1 conenction to don't read more data. This
flag replaces the H1C_F_IN_BUSY flag. Its name is a bit explicit. It is
automatically set on the backend side when the mux is created. It is safe to do
so because at this stage, the request has not yet been sent to the server. This
way, in h1_recv_allowed(), a test on this flag is enough to block the reads
instead of testing the H1 stream state on the backend side.

1 files changed, 28 insertions, 21 deletions

diff --git a/src/mux_h1.c b/src/mux_h1.c
index 3586a0aab..09d459b15 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -41,7 +41,6 @@
 /* Flags indicating why reading input data are blocked. */
 #define H1C_F_IN_ALLOC       0x00000010 /* mux is blocked on lack of input buffer */
 #define H1C_F_IN_FULL        0x00000020 /* mux is blocked on input buffer full */
-#define H1C_F_IN_BUSY        0x00000040 /* mux is blocked on input waiting the other side */
 /* 0x00000040 - 0x00000800 unused */
 
 /* Flags indicating the connection state */
@@ -57,6 +56,7 @@
 #define H1C_F_CO_MSG_MORE    0x00040000 /* set if CO_SFL_MSG_MORE must be set when calling xprt->snd_buf() */
 #define H1C_F_CO_STREAMER    0x00080000 /* set if CO_SFL_STREAMER must be set when calling xprt->snd_buf() */
 
+#define H1C_F_DONT_READ      0x00100000 /* Don't read more data for now */
 /*
  * H1 Stream flags (32 bits)
  */
@@ -367,12 +367,12 @@ static inline int h1_recv_allowed(const struct h1c *h1c)
 		return 0;
 	}
 
-	if (conn_is_back(h1c->conn) && h1c->h1s && h1c->h1s->req.state == H1_MSG_RQBEFORE) {
-		TRACE_DEVEL("recv not allowed because back and request not sent yet", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
+	if (h1c->flags & H1C_F_DONT_READ) {
+		TRACE_DEVEL("recv not allowed because dont_read", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
 		return 0;
 	}
 
-	if (!(h1c->flags & (H1C_F_IN_ALLOC|H1C_F_IN_FULL|H1C_F_IN_BUSY)))
+	if (!(h1c->flags & (H1C_F_IN_ALLOC|H1C_F_IN_FULL)))
 		return 1;
 
 	TRACE_DEVEL("recv not allowed because input is blocked", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
@@ -609,7 +609,7 @@ static void h1s_destroy(struct h1s *h1s)
 		if (h1s->subs)
 			h1s->subs->events = 0;
 
-		h1c->flags &= ~H1C_F_IN_BUSY;
+		h1c->flags &= ~H1C_F_DONT_READ;
 		if (h1s->flags & (H1S_F_REQ_ERROR|H1S_F_RES_ERROR)) {
 			h1c->flags |= H1C_F_CS_ERROR;
 			TRACE_STATE("h1s on error, set error on h1c", H1_EV_H1C_ERR, h1c->conn, h1s);
@@ -664,6 +664,7 @@ static int h1_init(struct connection *conn, struct proxy *proxy, struct session
 	h1c->wait_event.events   = 0;
 
 	if (conn_is_back(conn)) {
+		h1c->flags |= H1C_F_DONT_READ;
 		h1c->shut_timeout = h1c->timeout = proxy->timeout.server;
 		if (tick_isset(proxy->timeout.serverfin))
 			h1c->shut_timeout = proxy->timeout.serverfin;
@@ -693,7 +694,8 @@ static int h1_init(struct connection *conn, struct proxy *proxy, struct session
 		task_queue(t);
 
 	/* Try to read, if nothing is available yet we'll just subscribe */
-	h1c->conn->xprt->subscribe(h1c->conn, h1c->conn->xprt_ctx, SUB_RETRY_RECV, &h1c->wait_event);
+	if (!h1_recv_allowed(h1c))
+		h1c->conn->xprt->subscribe(h1c->conn, h1c->conn->xprt_ctx, SUB_RETRY_RECV, &h1c->wait_event);
 
 	/* mux->wake will be called soon to complete the operation */
 	TRACE_LEAVE(H1_EV_H1C_NEW, conn, h1c->h1s);
@@ -1121,14 +1123,14 @@ static void h1_set_req_tunnel_mode(struct h1s *h1s)
 	if (!conn_is_back(h1s->h1c->conn)) {
 		h1s->flags &= ~H1S_F_PARSING_DONE;
 		if (h1s->res.state < H1_MSG_DONE) {
-			h1s->h1c->flags |= H1C_F_IN_BUSY;
-			TRACE_STATE("switch h1c in busy mode", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1s->h1c->conn, h1s);
+			h1s->h1c->flags |= H1C_F_DONT_READ;
+			TRACE_STATE("Disable read on h1c", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1s->h1c->conn, h1s);
 		}
 	}
-	else if (h1s->h1c->flags & H1C_F_IN_BUSY) {
-		h1s->h1c->flags &= ~H1C_F_IN_BUSY;
+	else if (h1s->h1c->flags & H1C_F_DONT_READ) {
+		h1s->h1c->flags &= ~H1C_F_DONT_READ;
 		tasklet_wakeup(h1s->h1c->wait_event.tasklet);
-		TRACE_STATE("h1c no more busy", H1_EV_RX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1s->h1c->conn, h1s);
+		TRACE_STATE("Enable read on h1c", H1_EV_RX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1s->h1c->conn, h1s);
 	}
 }
 
@@ -1153,8 +1155,8 @@ static void h1_set_res_tunnel_mode(struct h1s *h1s)
 		 * it in tunnel mode.
 		 */
 		if (h1s->req.state < H1_MSG_DONE) {
-			h1s->h1c->flags |= H1C_F_IN_BUSY;
-			TRACE_STATE("switch h1c in busy mode", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1s->h1c->conn, h1s);
+			h1s->h1c->flags |= H1C_F_DONT_READ;
+			TRACE_STATE("Disable read on h1c", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1s->h1c->conn, h1s);
 		}
 		else if (h1s->status == 101 && h1s->req.state == H1_MSG_DONE) {
 			h1s->req.flags &= ~(H1_MF_XFER_LEN|H1_MF_CLEN|H1_MF_CHNK);
@@ -1162,10 +1164,10 @@ static void h1_set_res_tunnel_mode(struct h1s *h1s)
 			TRACE_STATE("switch H1 request in tunnel mode", H1_EV_TX_DATA|H1_EV_TX_HDRS, h1s->h1c->conn, h1s);
 		}
 	}
-	else if (h1s->h1c->flags & H1C_F_IN_BUSY) {
-		h1s->h1c->flags &= ~H1C_F_IN_BUSY;
+	else if (h1s->h1c->flags & H1C_F_DONT_READ) {
+		h1s->h1c->flags &= ~H1C_F_DONT_READ;
 		tasklet_wakeup(h1s->h1c->wait_event.tasklet);
-		TRACE_STATE("h1c no more busy", H1_EV_RX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1s->h1c->conn, h1s);
+		TRACE_STATE("Enable read on h1c", H1_EV_RX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1s->h1c->conn, h1s);
 	}
 }
 
@@ -1453,8 +1455,8 @@ static size_t h1_process_input(struct h1c *h1c, struct buffer *buf, size_t count
 			if (!(h1m->flags & H1_MF_RESP) && h1s->status == 101)
 				h1_set_req_tunnel_mode(h1s);
 			else if (h1s->req.state < H1_MSG_DONE || h1s->res.state < H1_MSG_DONE) {
-				h1c->flags |= H1C_F_IN_BUSY;
-				TRACE_STATE("switch h1c in busy mode", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1c->conn, h1s);
+				h1c->flags |= H1C_F_DONT_READ;
+				TRACE_STATE("Disable read on h1c", H1_EV_RX_DATA|H1_EV_H1C_BLK, h1c->conn, h1s);
 				break;
 			}
 			else
@@ -1648,6 +1650,11 @@ static size_t h1_process_output(struct h1c *h1c, struct buffer *buf, size_t coun
 				if (sl->flags & HTX_SL_F_BODYLESS)
 					h1m->flags |= H1_MF_CLEN;
 				h1m->state = H1_MSG_HDR_FIRST;
+				if (h1c->flags & H1C_F_DONT_READ) {
+					h1c->flags &= ~H1C_F_DONT_READ;
+					h1c->conn->xprt->subscribe(h1c->conn, h1c->conn->xprt_ctx, SUB_RETRY_RECV, &h1c->wait_event);
+					TRACE_STATE("Enable read on h1c", H1_EV_TX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1c->conn, h1s);
+				}
 				break;
 
 			case H1_MSG_RPBEFORE:
@@ -1903,10 +1910,10 @@ static size_t h1_process_output(struct h1c *h1c, struct buffer *buf, size_t coun
 					h1_set_req_tunnel_mode(h1s);
 					TRACE_STATE("switch H1 request in tunnel mode", H1_EV_TX_DATA|H1_EV_TX_HDRS, h1c->conn, h1s);
 				}
-				else if (h1s->h1c->flags & H1C_F_IN_BUSY) {
-					h1s->h1c->flags &= ~H1C_F_IN_BUSY;
+				else if (h1s->h1c->flags & H1C_F_DONT_READ) {
+					h1s->h1c->flags &= ~H1C_F_DONT_READ;
 					h1c->conn->xprt->subscribe(h1c->conn, h1c->conn->xprt_ctx, SUB_RETRY_RECV, &h1c->wait_event);
-					TRACE_STATE("h1c no more busy", H1_EV_TX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1c->conn, h1s);
+					TRACE_STATE("Enable read on h1c", H1_EV_TX_DATA|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1c->conn, h1s);
 				}
 
 				TRACE_USER((!(h1m->flags & H1_MF_RESP) ? "H1 request fully xferred" : "H1 response fully xferred"),