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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-28 19:43:44 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-28 20:40:47 +0300
commita11e1d432b51f63ba698d044441284a661f01144 (patch)
tree9f3c5a10bf0d7f9a342d5fb39c0c35ea14170124 /net/dccp/dccp.h
parentf57494321cbf5b1e7769b6135407d2995a369e28 (diff)
downloadlinux-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/dccp/dccp.h')
-rw-r--r--net/dccp/dccp.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 0ea2ee56ac1b..f91e3816806b 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -316,7 +316,8 @@ int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
int flags, int *addr_len);
void dccp_shutdown(struct sock *sk, int how);
int inet_dccp_listen(struct socket *sock, int backlog);
-__poll_t dccp_poll_mask(struct socket *sock, __poll_t events);
+__poll_t dccp_poll(struct file *file, struct socket *sock,
+ poll_table *wait);
int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
void dccp_req_err(struct sock *sk, u64 seq);