diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-28 19:43:44 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-28 20:40:47 +0300 |
| commit | a11e1d432b51f63ba698d044441284a661f01144 (patch) | |
| tree | 9f3c5a10bf0d7f9a342d5fb39c0c35ea14170124 /net/tipc | |
| parent | f57494321cbf5b1e7769b6135407d2995a369e28 (diff) | |
| download | linux-a11e1d432b51f63ba698d044441284a661f01144.tar.xz | |
Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL
The poll() changes were not well thought out, and completely
unexplained. They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.
Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead. That gets rid of one of the new indirections.
But that doesn't fix the new complexity that is completely unwarranted
for the regular case. The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.
[ This revert is a revert of about 30 different commits, not reverted
individually because that would just be unnecessarily messy - Linus ]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/tipc')
| -rw-r--r-- | net/tipc/socket.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 14a5d055717d..930852c54d7a 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -692,9 +692,10 @@ static int tipc_getname(struct socket *sock, struct sockaddr *uaddr, } /** - * tipc_poll - read pollmask + * tipc_poll - read and possibly block on pollmask * @file: file structure associated with the socket * @sock: socket for which to calculate the poll bits + * @wait: ??? * * Returns pollmask value * @@ -708,12 +709,15 @@ static int tipc_getname(struct socket *sock, struct sockaddr *uaddr, * imply that the operation will succeed, merely that it should be performed * and will not block. */ -static __poll_t tipc_poll_mask(struct socket *sock, __poll_t events) +static __poll_t tipc_poll(struct file *file, struct socket *sock, + poll_table *wait) { struct sock *sk = sock->sk; struct tipc_sock *tsk = tipc_sk(sk); __poll_t revents = 0; + sock_poll_wait(file, sk_sleep(sk), wait); + if (sk->sk_shutdown & RCV_SHUTDOWN) revents |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; if (sk->sk_shutdown == SHUTDOWN_MASK) @@ -3033,7 +3037,7 @@ static const struct proto_ops msg_ops = { .socketpair = tipc_socketpair, .accept = sock_no_accept, .getname = tipc_getname, - .poll_mask = tipc_poll_mask, + .poll = tipc_poll, .ioctl = tipc_ioctl, .listen = sock_no_listen, .shutdown = tipc_shutdown, @@ -3054,7 +3058,7 @@ static const struct proto_ops packet_ops = { .socketpair = tipc_socketpair, .accept = tipc_accept, .getname = tipc_getname, - .poll_mask = tipc_poll_mask, + .poll = tipc_poll, .ioctl = tipc_ioctl, .listen = tipc_listen, .shutdown = tipc_shutdown, @@ -3075,7 +3079,7 @@ static const struct proto_ops stream_ops = { .socketpair = tipc_socketpair, .accept = tipc_accept, .getname = tipc_getname, - .poll_mask = tipc_poll_mask, + .poll = tipc_poll, .ioctl = tipc_ioctl, .listen = tipc_listen, .shutdown = tipc_shutdown, |