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From: David Gibson <david@gibson.dropbear.id.au>
To: Stefano Brivio <sbrivio@redhat.com>, passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v2 05/18] tcp: Improve interface to tcp_l2_buf_flush()
Date: Fri,  9 Dec 2022 16:42:15 +1100	[thread overview]
Message-ID: <20221209054228.4085990-6-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221209054228.4085990-1-david@gibson.dropbear.id.au>

Currently this takes a msghdr, but the only thing we actually care about
in there in is the io vector.  Make it take an io vector directly.  We also
have a weird side effect of zeroing @buf_used.  Just pass this by value
and zero it in the caller instead.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tcp.c | 59 ++++++++++++++++++++++++-----------------------------------
 1 file changed, 24 insertions(+), 35 deletions(-)

diff --git a/tcp.c b/tcp.c
index 4050ea6..d96122d 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1413,22 +1413,27 @@ static int tcp_l2_buf_write_one(struct ctx *c, const struct iovec *iov)
 /**
  * tcp_l2_buf_flush_passt() - Send a message on the passt tap interface
  * @c:		Execution context
- * @mh:		Message header that was partially sent by sendmsg()
+ * @iov:	Pointer to array of buffers, one per frame
+ * @n:		Number of buffers/frames to flush
  */
-static void tcp_l2_buf_flush_passt(const struct ctx *c, const struct msghdr *mh)
+static void tcp_l2_buf_flush_passt(const struct ctx *c,
+				   const struct iovec *iov, size_t n)
 {
+	struct msghdr mh = {
+		.msg_iov = (void *)iov,
+		.msg_iovlen = n,
+	};
 	size_t end = 0, missing;
-	struct iovec *iov;
 	unsigned int i;
 	ssize_t sent;
 	char *p;
 
-	sent = sendmsg(c->fd_tap, mh, MSG_NOSIGNAL | MSG_DONTWAIT);
+	sent = sendmsg(c->fd_tap, &mh, MSG_NOSIGNAL | MSG_DONTWAIT);
 	if (sent < 0)
 		return;
 
 	/* Ensure a complete last message on partial sendmsg() */
-	for (i = 0, iov = mh->msg_iov; i < mh->msg_iovlen; i++, iov++) {
+	for (i = 0; i < n; i++, iov++) {
 		end += iov->iov_len;
 		if (end >= (size_t)sent)
 			break;
@@ -1446,30 +1451,24 @@ static void tcp_l2_buf_flush_passt(const struct ctx *c, const struct msghdr *mh)
 /**
  * tcp_l2_flags_buf_flush() - Send out buffers for segments with or without data
  * @c:		Execution context
- * @mh:		Message header pointing to buffers, msg_iovlen not set
- * @buf_used:	Pointer to count of used buffers, set to 0 on return
  */
-static void tcp_l2_buf_flush(struct ctx *c, struct msghdr *mh,
-			     unsigned int *buf_used)
+static void tcp_l2_buf_flush(struct ctx *c, const struct iovec *iov, size_t n)
 {
 	size_t i;
 
-	if (!(mh->msg_iovlen = *buf_used))
+	if (!n)
 		return;
 
 	if (c->mode == MODE_PASST) {
-		tcp_l2_buf_flush_passt(c, mh);
+		tcp_l2_buf_flush_passt(c, iov, n);
 	} else {
-		for (i = 0; i < mh->msg_iovlen; i++) {
-			struct iovec *iov = &mh->msg_iov[i];
-
-			if (tcp_l2_buf_write_one(c, iov))
+		for (i = 0; i < n; i++) {
+			if (tcp_l2_buf_write_one(c, iov + i))
 				i--;
 		}
 	}
-	*buf_used = 0;
 
-	pcap_multiple(mh->msg_iov, mh->msg_iovlen, sizeof(uint32_t));
+	pcap_multiple(iov, n, sizeof(uint32_t));
 }
 
 /**
@@ -1478,16 +1477,11 @@ static void tcp_l2_buf_flush(struct ctx *c, struct msghdr *mh,
  */
 static void tcp_l2_flags_buf_flush(struct ctx *c)
 {
-	struct msghdr mh = { 0 };
-	unsigned int *buf_used;
+	tcp_l2_buf_flush(c, tcp6_l2_flags_iov, tcp6_l2_flags_buf_used);
+	tcp6_l2_flags_buf_used = 0;
 
-	mh.msg_iov	= tcp6_l2_flags_iov;
-	buf_used	= &tcp6_l2_flags_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
-
-	mh.msg_iov	= tcp4_l2_flags_iov;
-	buf_used	= &tcp4_l2_flags_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp4_l2_flags_iov, tcp4_l2_flags_buf_used);
+	tcp4_l2_flags_buf_used = 0;
 }
 
 /**
@@ -1496,16 +1490,11 @@ static void tcp_l2_flags_buf_flush(struct ctx *c)
  */
 static void tcp_l2_data_buf_flush(struct ctx *c)
 {
-	struct msghdr mh = { 0 };
-	unsigned int *buf_used;
-
-	mh.msg_iov = tcp6_l2_iov;
-	buf_used	= &tcp6_l2_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp6_l2_iov, tcp6_l2_buf_used);
+	tcp6_l2_buf_used = 0;
 
-	mh.msg_iov = tcp4_l2_iov;
-	buf_used	= &tcp4_l2_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp4_l2_iov, tcp4_l2_buf_used);
+	tcp4_l2_buf_used = 0;
 }
 
 /**
-- 
@@ -1413,22 +1413,27 @@ static int tcp_l2_buf_write_one(struct ctx *c, const struct iovec *iov)
 /**
  * tcp_l2_buf_flush_passt() - Send a message on the passt tap interface
  * @c:		Execution context
- * @mh:		Message header that was partially sent by sendmsg()
+ * @iov:	Pointer to array of buffers, one per frame
+ * @n:		Number of buffers/frames to flush
  */
-static void tcp_l2_buf_flush_passt(const struct ctx *c, const struct msghdr *mh)
+static void tcp_l2_buf_flush_passt(const struct ctx *c,
+				   const struct iovec *iov, size_t n)
 {
+	struct msghdr mh = {
+		.msg_iov = (void *)iov,
+		.msg_iovlen = n,
+	};
 	size_t end = 0, missing;
-	struct iovec *iov;
 	unsigned int i;
 	ssize_t sent;
 	char *p;
 
-	sent = sendmsg(c->fd_tap, mh, MSG_NOSIGNAL | MSG_DONTWAIT);
+	sent = sendmsg(c->fd_tap, &mh, MSG_NOSIGNAL | MSG_DONTWAIT);
 	if (sent < 0)
 		return;
 
 	/* Ensure a complete last message on partial sendmsg() */
-	for (i = 0, iov = mh->msg_iov; i < mh->msg_iovlen; i++, iov++) {
+	for (i = 0; i < n; i++, iov++) {
 		end += iov->iov_len;
 		if (end >= (size_t)sent)
 			break;
@@ -1446,30 +1451,24 @@ static void tcp_l2_buf_flush_passt(const struct ctx *c, const struct msghdr *mh)
 /**
  * tcp_l2_flags_buf_flush() - Send out buffers for segments with or without data
  * @c:		Execution context
- * @mh:		Message header pointing to buffers, msg_iovlen not set
- * @buf_used:	Pointer to count of used buffers, set to 0 on return
  */
-static void tcp_l2_buf_flush(struct ctx *c, struct msghdr *mh,
-			     unsigned int *buf_used)
+static void tcp_l2_buf_flush(struct ctx *c, const struct iovec *iov, size_t n)
 {
 	size_t i;
 
-	if (!(mh->msg_iovlen = *buf_used))
+	if (!n)
 		return;
 
 	if (c->mode == MODE_PASST) {
-		tcp_l2_buf_flush_passt(c, mh);
+		tcp_l2_buf_flush_passt(c, iov, n);
 	} else {
-		for (i = 0; i < mh->msg_iovlen; i++) {
-			struct iovec *iov = &mh->msg_iov[i];
-
-			if (tcp_l2_buf_write_one(c, iov))
+		for (i = 0; i < n; i++) {
+			if (tcp_l2_buf_write_one(c, iov + i))
 				i--;
 		}
 	}
-	*buf_used = 0;
 
-	pcap_multiple(mh->msg_iov, mh->msg_iovlen, sizeof(uint32_t));
+	pcap_multiple(iov, n, sizeof(uint32_t));
 }
 
 /**
@@ -1478,16 +1477,11 @@ static void tcp_l2_buf_flush(struct ctx *c, struct msghdr *mh,
  */
 static void tcp_l2_flags_buf_flush(struct ctx *c)
 {
-	struct msghdr mh = { 0 };
-	unsigned int *buf_used;
+	tcp_l2_buf_flush(c, tcp6_l2_flags_iov, tcp6_l2_flags_buf_used);
+	tcp6_l2_flags_buf_used = 0;
 
-	mh.msg_iov	= tcp6_l2_flags_iov;
-	buf_used	= &tcp6_l2_flags_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
-
-	mh.msg_iov	= tcp4_l2_flags_iov;
-	buf_used	= &tcp4_l2_flags_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp4_l2_flags_iov, tcp4_l2_flags_buf_used);
+	tcp4_l2_flags_buf_used = 0;
 }
 
 /**
@@ -1496,16 +1490,11 @@ static void tcp_l2_flags_buf_flush(struct ctx *c)
  */
 static void tcp_l2_data_buf_flush(struct ctx *c)
 {
-	struct msghdr mh = { 0 };
-	unsigned int *buf_used;
-
-	mh.msg_iov = tcp6_l2_iov;
-	buf_used	= &tcp6_l2_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp6_l2_iov, tcp6_l2_buf_used);
+	tcp6_l2_buf_used = 0;
 
-	mh.msg_iov = tcp4_l2_iov;
-	buf_used	= &tcp4_l2_buf_used;
-	tcp_l2_buf_flush(c, &mh, buf_used);
+	tcp_l2_buf_flush(c, tcp4_l2_iov, tcp4_l2_buf_used);
+	tcp4_l2_buf_used = 0;
 }
 
 /**
-- 
2.38.1


  parent reply	other threads:[~2022-12-09  5:42 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-09  5:42 [PATCH v2 00/18] RFC: Unify and simplify tap send path David Gibson
2022-12-09  5:42 ` [PATCH v2 01/18] pcap: Introduce pcap_frame() helper David Gibson
2023-01-04 17:45   ` Stefano Brivio
2023-01-05  4:47     ` David Gibson
2022-12-09  5:42 ` [PATCH v2 02/18] pcap: Replace pcapm() with pcap_multiple() David Gibson
2022-12-09  5:42 ` [PATCH v2 03/18] tcp: Combine two parts of passt tap send path together David Gibson
2022-12-09  5:42 ` [PATCH v2 04/18] tcp: Don't keep compute total bytes in a message until we need it David Gibson
2023-01-04 17:45   ` Stefano Brivio
2023-01-05  4:48     ` David Gibson
2022-12-09  5:42 ` David Gibson [this message]
2023-01-04 17:45   ` [PATCH v2 05/18] tcp: Improve interface to tcp_l2_buf_flush() Stefano Brivio
2023-01-05  4:53     ` David Gibson
2022-12-09  5:42 ` [PATCH v2 06/18] tcp: Combine two parts of pasta tap send path together David Gibson
2022-12-09  5:42 ` [PATCH v2 07/18] tap, tcp: Move tap send path to tap.c David Gibson
2022-12-09  5:42 ` [PATCH v2 08/18] util: Introduce hton*_constant() in place of #ifdefs David Gibson
2022-12-09  5:42 ` [PATCH v2 09/18] tcp, udp: Use named field initializers in iov_init functions David Gibson
2022-12-09  5:42 ` [PATCH v2 10/18] util: Parameterize ethernet header initializer macro David Gibson
2022-12-09  5:42 ` [PATCH v2 11/18] tcp: Remove redundant and incorrect initialization from *_iov_init() David Gibson
2022-12-09  5:42 ` [PATCH v2 12/18] tcp: Consolidate calculation of total frame size David Gibson
2022-12-09  5:42 ` [PATCH v2 13/18] tap: Add "tap headers" abstraction David Gibson
2022-12-09  5:42 ` [PATCH v2 14/18] tcp: Use abstracted tap header David Gibson
2022-12-09  5:42 ` [PATCH v2 15/18] tap: Use different io vector bases depending on tap type David Gibson
2022-12-09  5:42 ` [PATCH v2 16/18] udp: Use abstracted tap header David Gibson
2022-12-09  5:42 ` [PATCH v2 17/18] udp: Use tap_send_frames() David Gibson
2023-01-04 17:45   ` Stefano Brivio
2023-01-05  4:54     ` David Gibson
2022-12-09  5:42 ` [PATCH v2 18/18] tap: Improve handling of partial frame sends David Gibson
2023-01-04 17:45   ` Stefano Brivio
2023-01-05  4:57     ` David Gibson
2023-01-04 17:45 ` [PATCH v2 00/18] RFC: Unify and simplify tap send path Stefano Brivio

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