MINOR: stconn: Use a dedicated function to get the opposite sedesc

se_opposite() function is added to let an endpoint retrieve the opposite
endpoint descriptor. Muxes supportng the zero-copy forwarding can now use
it. The se_shutdown() function too. This will be use by the SPOP multiplexer
to be able to retrieve the SPOE agent configuration attached to the applet
on client side.

The related issue is #2502.

include/haproxy/stconn.h

@@ -27,6 +27,7 @@
 #include <haproxy/htx-t.h>
 #include <haproxy/obj_type.h>
 #include <haproxy/stconn-t.h>
+#include <haproxy/xref.h>
 
 struct buffer;
 struct session;
@@ -134,6 +135,19 @@ static inline size_t se_ff_data(struct sedesc *se)
 	return (se->iobuf.data + (se->iobuf.pipe ? se->iobuf.pipe->data : 0));
 }
 
+
+static inline struct sedesc *se_opposite(struct sedesc *se)
+{
+	struct xref *peer = xref_get_peer_and_lock(&se->xref);
+	struct sedesc *seo = NULL;;
+
+	if (peer) {
+		seo = container_of(peer, struct sedesc, xref);
+		xref_unlock(&se->xref, peer);
+	}
+	return seo;
+}
+
 /* stream connector version */
 static forceinline void sc_ep_zero(struct stconn *sc)
 {

src/applet.c

@@ -25,7 +25,6 @@
 #include <haproxy/task.h>
 #include <haproxy/trace.h>
 #include <haproxy/vecpair.h>
-#include <haproxy/xref.h>
 
 unsigned int nb_applets = 0;
 
@@ -646,7 +645,6 @@ size_t appctx_snd_buf(struct stconn *sc, struct buffer *buf, size_t count, unsig
 int appctx_fastfwd(struct stconn *sc, unsigned int count, unsigned int flags)
 {
 	struct appctx *appctx = __sc_appctx(sc);
-	struct xref *peer;
 	struct sedesc *sdo = NULL;
 	unsigned int len, nego_flags = NEGO_FF_FL_NONE;
 	int ret = 0;
@@ -661,13 +659,11 @@ int appctx_fastfwd(struct stconn *sc, unsigned int count, unsigned int flags)
 		return -1;
 	}
 
-	peer = xref_get_peer_and_lock(&appctx->sedesc->xref);
+	sdo = se_opposite(appctx->sedesc);
-	if (!peer) {
+	if (!sdo) {
 		TRACE_STATE("Opposite endpoint not available yet", APPLET_EV_RECV, appctx);
 		goto end;
 	}
-	sdo = container_of(peer, struct sedesc, xref);
-	xref_unlock(&appctx->sedesc->xref, peer);
 
 	if (appctx->to_forward && count > appctx->to_forward) {
 		count = appctx->to_forward;

src/mux_h1.c

@@ -31,7 +31,6 @@
 #include <haproxy/stconn.h>
 #include <haproxy/stream.h>
 #include <haproxy/trace.h>
-#include <haproxy/xref.h>
 
 /* H1 connection descriptor */
 struct h1c {
@@ -4603,16 +4602,7 @@ static size_t h1_snd_buf(struct stconn *sc, struct buffer *buf, size_t count, in
 
 static inline struct sedesc *h1s_opposite_sd(struct h1s *h1s)
 {
-	struct xref *peer;
+	return se_opposite(h1s->sd);
-	struct sedesc *sdo;
-
-	peer = xref_get_peer_and_lock(&h1s->sd->xref);
-	if (!peer)
-		return NULL;
-
-	sdo = container_of(peer, struct sedesc, xref);
-	xref_unlock(&h1s->sd->xref, peer);
-	return sdo;
 }
 
 static size_t h1_nego_ff(struct stconn *sc, struct buffer *input, size_t count, unsigned int flags)

src/mux_pt.c

@@ -19,7 +19,6 @@
 #include <haproxy/stream.h>
 #include <haproxy/task.h>
 #include <haproxy/trace.h>
-#include <haproxy/xref.h>
 
 struct mux_pt_ctx {
 	struct sedesc *sd;
@@ -561,16 +560,7 @@ static size_t mux_pt_snd_buf(struct stconn *sc, struct buffer *buf, size_t count
 
 static inline struct sedesc *mux_pt_opposite_sd(struct mux_pt_ctx *ctx)
 {
-	struct xref *peer;
+	return se_opposite(ctx->sd);
-	struct sedesc *sdo;
-
-	peer = xref_get_peer_and_lock(&ctx->sd->xref);
-	if (!peer)
-		return NULL;
-
-	sdo = container_of(peer, struct sedesc, xref);
-	xref_unlock(&ctx->sd->xref, peer);
-	return sdo;
 }
 
 static size_t mux_pt_nego_ff(struct stconn *sc, struct buffer *input, size_t count, unsigned int flags)

src/stconn.c

@@ -141,6 +141,8 @@ void sedesc_free(struct sedesc *sedesc)
  */
 void se_shutdown(struct sedesc *sedesc, enum se_shut_mode mode)
 {
+	struct sedesc *sdo;
+	struct se_abort_info *reason = NULL;
 	unsigned int flags = 0;
 
 	if ((mode & (SE_SHW_SILENT|SE_SHW_NORMAL)) && !se_fl_test(sedesc, SE_FL_SHW))
@@ -153,16 +155,9 @@ void se_shutdown(struct sedesc *sedesc, enum se_shut_mode mode)
 
 		if (flags) {
 			if (mux && mux->shut) {
-				struct se_abort_info *reason = NULL;
+				sdo = se_opposite(sedesc);
-				struct xref *peer = xref_get_peer_and_lock(&sedesc->xref);
+				if (sdo)
-
-				if (peer) {
-					struct sedesc *sdo = container_of(peer, struct sedesc, xref);
-
 					reason = &sdo->abort_info;
-					xref_unlock(&sedesc->xref, peer);
-				}
-
 				mux->shut(sedesc->sc, mode, reason);
 			}
 			se_fl_set(sedesc, flags);
@@ -173,16 +168,9 @@ void se_shutdown(struct sedesc *sedesc, enum se_shut_mode mode)
 
 		if (flags) {
 			if (appctx->applet->shut) {
-				struct se_abort_info *reason = NULL;
+				sdo = se_opposite(sedesc);
-				struct xref *peer = xref_get_peer_and_lock(&sedesc->xref);
+				if (sdo)
-
-				if (peer) {
-					struct sedesc *sdo = container_of(peer, struct sedesc, xref);
-
 					reason = &sdo->abort_info;
-					xref_unlock(&sedesc->xref, peer);
-				}
-
 				appctx->applet->shut(appctx, mode, reason);
 			}
 			se_fl_set(sedesc, flags);