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 06/18] tcp: Combine two parts of pasta tap send path together
Date: Fri, 9 Dec 2022 16:42:16 +1100 [thread overview]
Message-ID: <20221209054228.4085990-7-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221209054228.4085990-1-david@gibson.dropbear.id.au>
tcp_l2_buf_flush() open codes the loop across each frame in a group, but
but calls tcp_l2_buf_write_one() to send each frame to the pasta tuntap
device. Combine these two pasta-specific operations into
tcp_l2_buf_flush_pasta() which is a little cleaner and will enable further
cleanups.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp.c | 40 ++++++++++++++++++----------------------
1 file changed, 18 insertions(+), 22 deletions(-)
diff --git a/tcp.c b/tcp.c
index d96122d..9960a35 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1391,23 +1391,25 @@ static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
} while (0)
/**
- * tcp_l2_buf_write_one() - Write a single buffer to tap file descriptor
+ * tcp_l2_buf_flush_pasta() - Send frames on the pasta tap interface
* @c: Execution context
- * @iov: struct iovec item pointing to buffer
- * @ts: Current timestamp
- *
- * Return: 0 on success, negative error code on failure (tap reset possible)
+ * @iov: Pointer to array of buffers, one per frame
+ * @n: Number of buffers/frames to flush
*/
-static int tcp_l2_buf_write_one(struct ctx *c, const struct iovec *iov)
+static void tcp_l2_buf_flush_pasta(struct ctx *c,
+ const struct iovec *iov, size_t n)
{
- if (write(c->fd_tap, (char *)iov->iov_base + 4, iov->iov_len - 4) < 0) {
- debug("tap write: %s", strerror(errno));
- if (errno != EAGAIN && errno != EWOULDBLOCK)
- tap_handler(c, c->fd_tap, EPOLLERR, NULL);
- return -errno;
- }
+ size_t i;
- return 0;
+ for (i = 0; i < n; i++) {
+ if (write(c->fd_tap, (char *)iov->iov_base + 4,
+ iov->iov_len - 4) < 0) {
+ debug("tap write: %s", strerror(errno));
+ if (errno != EAGAIN && errno != EWOULDBLOCK)
+ tap_handler(c, c->fd_tap, EPOLLERR, NULL);
+ i--;
+ }
+ }
}
/**
@@ -1454,19 +1456,13 @@ static void tcp_l2_buf_flush_passt(const struct ctx *c,
*/
static void tcp_l2_buf_flush(struct ctx *c, const struct iovec *iov, size_t n)
{
- size_t i;
-
if (!n)
return;
- if (c->mode == MODE_PASST) {
+ if (c->mode == MODE_PASST)
tcp_l2_buf_flush_passt(c, iov, n);
- } else {
- for (i = 0; i < n; i++) {
- if (tcp_l2_buf_write_one(c, iov + i))
- i--;
- }
- }
+ else
+ tcp_l2_buf_flush_pasta(c, iov, n);
pcap_multiple(iov, n, sizeof(uint32_t));
}
--
@@ -1391,23 +1391,25 @@ static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
} while (0)
/**
- * tcp_l2_buf_write_one() - Write a single buffer to tap file descriptor
+ * tcp_l2_buf_flush_pasta() - Send frames on the pasta tap interface
* @c: Execution context
- * @iov: struct iovec item pointing to buffer
- * @ts: Current timestamp
- *
- * Return: 0 on success, negative error code on failure (tap reset possible)
+ * @iov: Pointer to array of buffers, one per frame
+ * @n: Number of buffers/frames to flush
*/
-static int tcp_l2_buf_write_one(struct ctx *c, const struct iovec *iov)
+static void tcp_l2_buf_flush_pasta(struct ctx *c,
+ const struct iovec *iov, size_t n)
{
- if (write(c->fd_tap, (char *)iov->iov_base + 4, iov->iov_len - 4) < 0) {
- debug("tap write: %s", strerror(errno));
- if (errno != EAGAIN && errno != EWOULDBLOCK)
- tap_handler(c, c->fd_tap, EPOLLERR, NULL);
- return -errno;
- }
+ size_t i;
- return 0;
+ for (i = 0; i < n; i++) {
+ if (write(c->fd_tap, (char *)iov->iov_base + 4,
+ iov->iov_len - 4) < 0) {
+ debug("tap write: %s", strerror(errno));
+ if (errno != EAGAIN && errno != EWOULDBLOCK)
+ tap_handler(c, c->fd_tap, EPOLLERR, NULL);
+ i--;
+ }
+ }
}
/**
@@ -1454,19 +1456,13 @@ static void tcp_l2_buf_flush_passt(const struct ctx *c,
*/
static void tcp_l2_buf_flush(struct ctx *c, const struct iovec *iov, size_t n)
{
- size_t i;
-
if (!n)
return;
- if (c->mode == MODE_PASST) {
+ if (c->mode == MODE_PASST)
tcp_l2_buf_flush_passt(c, iov, n);
- } else {
- for (i = 0; i < n; i++) {
- if (tcp_l2_buf_write_one(c, iov + i))
- i--;
- }
- }
+ else
+ tcp_l2_buf_flush_pasta(c, iov, n);
pcap_multiple(iov, n, sizeof(uint32_t));
}
--
2.38.1
next prev 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 ` [PATCH v2 05/18] tcp: Improve interface to tcp_l2_buf_flush() David Gibson
2023-01-04 17:45 ` Stefano Brivio
2023-01-05 4:53 ` David Gibson
2022-12-09 5:42 ` David Gibson [this message]
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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