From: Felix Fietkau <nbd@openwrt.org>
Date: Sun, 30 Dec 2012 18:21:03 +0000 (+0100)
Subject: ustream: avoid calling s->poll from a write path to avoid looping back through the... 
X-Git-Url: http://git.archive.openwrt.org/?p=project%2Flibubox.git;a=commitdiff_plain;h=29c066cfd60cc9101201a2c31a9aa66288288719

ustream: avoid calling s->poll from a write path to avoid looping back through the notify_write cb

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---

diff --git a/ustream-fd.c b/ustream-fd.c
index 0cd2eb3..93fd501 100644
--- a/ustream-fd.c
+++ b/ustream-fd.c
@@ -21,7 +21,7 @@
 #include <stdio.h>
 #include "ustream.h"
 
-static void ustream_fd_set_uloop(struct ustream *s)
+static void ustream_fd_set_uloop(struct ustream *s, bool write)
 {
 	struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 	struct ustream_buf *buf;
@@ -31,7 +31,7 @@ static void ustream_fd_set_uloop(struct ustream *s)
 		flags |= ULOOP_READ;
 
 	buf = s->w.head;
-	if (buf && s->w.data_bytes && !s->write_error)
+	if (write || (buf && s->w.data_bytes && !s->write_error))
 		flags |= ULOOP_WRITE;
 
 	uloop_fd_add(&sf->fd, flags);
@@ -40,6 +40,11 @@ static void ustream_fd_set_uloop(struct ustream *s)
 		sf->fd.cb(&sf->fd, ULOOP_READ);
 }
 
+static void ustream_fd_set_read_blocked(struct ustream *s)
+{
+	ustream_fd_set_uloop(s, false);
+}
+
 static void ustream_fd_read_pending(struct ustream_fd *sf, bool *more)
 {
 	struct ustream *s = &sf->stream;
@@ -89,9 +94,12 @@ retry:
 			goto retry;
 
 		if (errno == EAGAIN || errno == EWOULDBLOCK)
-			return 0;
+			len = 0;
 	}
 
+	if (len >= 0 && len < buflen)
+		ustream_fd_set_uloop(s, true);
+
 	return len;
 }
 
@@ -106,12 +114,12 @@ static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events)
 
 	if (events & ULOOP_WRITE) {
 		if (!ustream_write_pending(s))
-			ustream_fd_set_uloop(s);
+			ustream_fd_set_uloop(s, false);
 	}
 
 	if (!s->eof && fd->eof) {
 		s->eof = true;
-		ustream_fd_set_uloop(s);
+		ustream_fd_set_uloop(s, false);
 		ustream_state_change(s);
 	}
 
@@ -147,9 +155,9 @@ void ustream_fd_init(struct ustream_fd *sf, int fd)
 
 	sf->fd.fd = fd;
 	sf->fd.cb = ustream_uloop_cb;
-	s->set_read_blocked = ustream_fd_set_uloop;
+	s->set_read_blocked = ustream_fd_set_read_blocked;
 	s->write = ustream_fd_write;
 	s->free = ustream_fd_free;
 	s->poll = ustream_fd_poll;
-	ustream_fd_set_uloop(s);
+	ustream_fd_set_uloop(s, false);
 }
diff --git a/ustream.c b/ustream.c
index 37fbaf7..9c61806 100644
--- a/ustream.c
+++ b/ustream.c
@@ -379,7 +379,6 @@ static int ustream_write_buffered(struct ustream *s, const char *data, int len,
 	struct ustream_buf_list *l = &s->w;
 	struct ustream_buf *buf;
 	int maxlen;
-	bool has_data = !!s->w.data_bytes;
 
 	while (len) {
 		if (!ustream_prepare_buf(s, &s->w, len))
@@ -399,9 +398,6 @@ static int ustream_write_buffered(struct ustream *s, const char *data, int len,
 		l->data_bytes += maxlen;
 	}
 
-	if (s->poll && !has_data)
-		s->poll(s);
-
 	return wr;
 }