From: Willy Tarreau <w@1wt.eu>
Date: Fri, 11 Oct 2024 12:49:45 +0000 (+0200)
Subject: MINOR: mux-h2: simplify the wake up code in h2_rcv_buf()
X-Git-Tag: v3.1-dev10~83
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b74bedf1579be48ddec1ed5e28b22647e790d991;p=thirdparty%2Fhaproxy.git

MINOR: mux-h2: simplify the wake up code in h2_rcv_buf()

The code used to decide when to restart reading is far from being trivial
and will cause trouble after the forthcoming changes: it checks if the
current stream is the same that is being demuxed, and only if so, wakes
the demux to restart reading. Once streams will start to use multiple
buffers, this condition will make no sense anymore. Actually the real
reason is split into two steps:
  - detect if the demux is currently blocked on the current stream, and
    if so remove SFULL
  - detect if any demux blocking flags were removed during the operations,
    and if so, wake demuxing.

For now this doesn't change anything.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 2ee5e270d0..0167dd9e9b 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -7193,6 +7193,7 @@ static size_t h2_rcv_buf(struct stconn *sc, struct buffer *buf, size_t count, in
 	struct htx *h2s_htx = NULL;
 	struct htx *buf_htx = NULL;
 	size_t ret = 0;
+	uint prev_h2c_flags = h2c->flags;
 
 	TRACE_ENTER(H2_EV_STRM_RECV, h2c->conn, h2s);
 
@@ -7255,11 +7256,13 @@ static size_t h2_rcv_buf(struct stconn *sc, struct buffer *buf, size_t count, in
 		h2s_propagate_term_flags(h2c, h2s);
 	}
 
-	if (ret && h2c->dsi == h2s->id) {
-		/* demux is blocking on this stream's buffer */
+	/* the demux might have been blocking on this stream's buffer */
+	if (ret && h2c->dsi == h2s->id)
 		h2c->flags &= ~H2_CF_DEM_SFULL;
+
+	/* wake up processing if we've unblocked something */
+	if ((prev_h2c_flags & ~h2c->flags) & H2_CF_DEM_SFULL)
 		h2c_restart_reading(h2c, 1);
-	}
 
 	TRACE_LEAVE(H2_EV_STRM_RECV, h2c->conn, h2s);
 	return ret;