From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v2 05/11] tcp_splice: Avoid awkward temporaries in tcp_splice_epoll_ctl()
Date: Tue, 7 Nov 2023 13:42:44 +1100 [thread overview]
Message-ID: <20231107024250.2290959-6-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20231107024250.2290959-1-david@gibson.dropbear.id.au>
We initialise the events_a and events_b variables with
tcp_splice_conn_epoll_events() function, then immediately copy the values
into ev_a.events and ev_b.events. We can't simply pass &ev_[ab].events to
tcp_splice_conn_epoll_events(), because struct epoll_event is packed,
leading to 'pointer may be unaligned' warnings if we attempt that.
We can, however, make tcp_splice_conn_epoll_events() take struct
epoll_event pointers rather than raw u32 pointers, avoiding the awkward
temporaries.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp_splice.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/tcp_splice.c b/tcp_splice.c
index 44d1e4a..a706ebb 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -95,25 +95,26 @@ static int tcp_sock_refill_ns(void *arg);
/**
* tcp_splice_conn_epoll_events() - epoll events masks for given state
* @events: Connection event flags
- * @a: Event mask for socket with accepted connection, set on return
- * @b: Event mask for connection target socket, set on return
+ * @a: Event for socket with accepted connection, set on return
+ * @b: Event for connection target socket, set on return
*/
static void tcp_splice_conn_epoll_events(uint16_t events,
- uint32_t *a, uint32_t *b)
+ struct epoll_event *a,
+ struct epoll_event *b)
{
- *a = *b = 0;
+ a->events = b->events = 0;
if (events & SPLICE_ESTABLISHED) {
if (!(events & B_FIN_SENT))
- *a = EPOLLIN | EPOLLRDHUP;
+ a->events = EPOLLIN | EPOLLRDHUP;
if (!(events & A_FIN_SENT))
- *b = EPOLLIN | EPOLLRDHUP;
+ b->events = EPOLLIN | EPOLLRDHUP;
} else if (events & SPLICE_CONNECT) {
- *b = EPOLLOUT;
+ b->events = EPOLLOUT;
}
- *a |= (events & A_OUT_WAIT) ? EPOLLOUT : 0;
- *b |= (events & B_OUT_WAIT) ? EPOLLOUT : 0;
+ a->events |= (events & A_OUT_WAIT) ? EPOLLOUT : 0;
+ b->events |= (events & B_OUT_WAIT) ? EPOLLOUT : 0;
}
/**
@@ -133,11 +134,8 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,
.tcp.index = CONN_IDX(conn) };
struct epoll_event ev_a = { .data.u64 = ref_a.u64 };
struct epoll_event ev_b = { .data.u64 = ref_b.u64 };
- uint32_t events_a, events_b;
- tcp_splice_conn_epoll_events(conn->events, &events_a, &events_b);
- ev_a.events = events_a;
- ev_b.events = events_b;
+ tcp_splice_conn_epoll_events(conn->events, &ev_a, &ev_b);
if (epoll_ctl(c->epollfd, m, conn->a, &ev_a) ||
epoll_ctl(c->epollfd, m, conn->b, &ev_b)) {
--
@@ -95,25 +95,26 @@ static int tcp_sock_refill_ns(void *arg);
/**
* tcp_splice_conn_epoll_events() - epoll events masks for given state
* @events: Connection event flags
- * @a: Event mask for socket with accepted connection, set on return
- * @b: Event mask for connection target socket, set on return
+ * @a: Event for socket with accepted connection, set on return
+ * @b: Event for connection target socket, set on return
*/
static void tcp_splice_conn_epoll_events(uint16_t events,
- uint32_t *a, uint32_t *b)
+ struct epoll_event *a,
+ struct epoll_event *b)
{
- *a = *b = 0;
+ a->events = b->events = 0;
if (events & SPLICE_ESTABLISHED) {
if (!(events & B_FIN_SENT))
- *a = EPOLLIN | EPOLLRDHUP;
+ a->events = EPOLLIN | EPOLLRDHUP;
if (!(events & A_FIN_SENT))
- *b = EPOLLIN | EPOLLRDHUP;
+ b->events = EPOLLIN | EPOLLRDHUP;
} else if (events & SPLICE_CONNECT) {
- *b = EPOLLOUT;
+ b->events = EPOLLOUT;
}
- *a |= (events & A_OUT_WAIT) ? EPOLLOUT : 0;
- *b |= (events & B_OUT_WAIT) ? EPOLLOUT : 0;
+ a->events |= (events & A_OUT_WAIT) ? EPOLLOUT : 0;
+ b->events |= (events & B_OUT_WAIT) ? EPOLLOUT : 0;
}
/**
@@ -133,11 +134,8 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,
.tcp.index = CONN_IDX(conn) };
struct epoll_event ev_a = { .data.u64 = ref_a.u64 };
struct epoll_event ev_b = { .data.u64 = ref_b.u64 };
- uint32_t events_a, events_b;
- tcp_splice_conn_epoll_events(conn->events, &events_a, &events_b);
- ev_a.events = events_a;
- ev_b.events = events_b;
+ tcp_splice_conn_epoll_events(conn->events, &ev_a, &ev_b);
if (epoll_ctl(c->epollfd, m, conn->a, &ev_a) ||
epoll_ctl(c->epollfd, m, conn->b, &ev_b)) {
--
2.41.0
next prev parent reply other threads:[~2023-11-07 2:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 2:42 [PATCH v2 00/11] tcp_splice: Better exploit symmetry between sides of connection David Gibson
2023-11-07 2:42 ` [PATCH v2 01/11] tcp_splice: Remove redundant tcp_splice_epoll_ctl() David Gibson
2023-11-07 2:42 ` [PATCH v2 02/11] tcp_splice: Correct error handling in tcp_splice_epoll_ctl() David Gibson
2023-11-07 2:42 ` [PATCH v2 03/11] tcp_splice: Don't handle EPOLL_CTL_DEL as part of tcp_splice_epoll_ctl() David Gibson
2023-11-07 2:42 ` [PATCH v2 04/11] tcp_splice: Remove unnecessary forward declaration David Gibson
2023-11-07 2:42 ` David Gibson [this message]
2023-11-07 2:42 ` [PATCH v2 06/11] tcp_splice: Don't pool pipes in pairs David Gibson
2023-11-07 2:42 ` [PATCH v2 07/11] tcp_splice: Rename sides of connection from a/b to 0/1 David Gibson
2023-11-07 2:42 ` [PATCH v2 08/11] tcp_splice: Exploit side symmetry in tcp_splice_timer() David Gibson
2023-11-07 2:42 ` [PATCH v2 09/11] tcp_splice: Exploit side symmetry in tcp_splice_connect_finish() David Gibson
2023-11-07 2:42 ` [PATCH v2 10/11] tcp_splice: Exploit side symmetry in tcp_splice_destroy() David Gibson
2023-11-07 2:42 ` [PATCH v2 11/11] tcp_splice: Simplify selection of socket and pipe sides in socket handler David Gibson
2023-11-07 12:45 ` [PATCH v2 00/11] tcp_splice: Better exploit symmetry between sides of connection Stefano Brivio
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231107024250.2290959-6-david@gibson.dropbear.id.au \
--to=david@gibson.dropbear.id.au \
--cc=passt-dev@passt.top \
--cc=sbrivio@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://passt.top/passt
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for IMAP folder(s).