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io_uring/net: wire up IORING_CQE_F_SOCK_NONEMPTY for accept

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If the given protocol supports passing back whether or not we had more
pending accept post this one, pass back this information to userspace.
This is done by setting IORING_CQE_F_SOCK_NONEMPTY in the CQE flags,
just like we do for recv/recvmsg if there's more data available post
a receive operation.

We can also use this information to be smarter about multishot retry,
as we don't need to do a pointless retry if we know for a fact that
there aren't any more connections to accept.

Suggested-by: Norman Maurer <norman_maurer@apple.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2024-05-09 09:41:10 -06:00
parent 7951e36ac6
commit ac287da2e0
1 changed files with 16 additions and 4 deletions
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20
io_uring/net.c
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@ -1533,6 +1533,7 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
.flags = force_nonblock ? O_NONBLOCK : 0,
};
struct file *file;
unsigned cflags;
int ret, fd;
if (!(req->flags & REQ_F_POLLED) &&
@ -1545,6 +1546,8 @@ retry:
if (unlikely(fd < 0))
return fd;
}
arg.err = 0;
arg.is_empty = -1;
file = do_accept(req->file, &arg, accept->addr, accept->addr_len,
accept->flags);
if (IS_ERR(file)) {
@ -1573,17 +1576,26 @@ retry:
accept->file_slot);
}
cflags = 0;
if (!arg.is_empty)
cflags |= IORING_CQE_F_SOCK_NONEMPTY;
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
io_req_set_res(req, ret, 0);
io_req_set_res(req, ret, cflags);
return IOU_OK;
}
if (ret < 0)
return ret;
if (io_req_post_cqe(req, ret, IORING_CQE_F_MORE))
goto retry;
if (io_req_post_cqe(req, ret, cflags | IORING_CQE_F_MORE)) {
if (cflags & IORING_CQE_F_SOCK_NONEMPTY || arg.is_empty == -1)
goto retry;
if (issue_flags & IO_URING_F_MULTISHOT)
return IOU_ISSUE_SKIP_COMPLETE;
return -EAGAIN;
}
io_req_set_res(req, ret, 0);
io_req_set_res(req, ret, cflags);
return IOU_STOP_MULTISHOT;
}