io_uring/net: wire up IORING_CQE_F_SOCK_NONEMPTY for accept

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

View File

@ -1533,6 +1533,7 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
.flags = force_nonblock ? O_NONBLOCK : 0, .flags = force_nonblock ? O_NONBLOCK : 0,
}; };
struct file *file; struct file *file;
unsigned cflags;
int ret, fd; int ret, fd;
if (!(req->flags & REQ_F_POLLED) && if (!(req->flags & REQ_F_POLLED) &&
@ -1545,6 +1546,8 @@ retry:
if (unlikely(fd < 0)) if (unlikely(fd < 0))
return fd; return fd;
} }
arg.err = 0;
arg.is_empty = -1;
file = do_accept(req->file, &arg, accept->addr, accept->addr_len, file = do_accept(req->file, &arg, accept->addr, accept->addr_len,
accept->flags); accept->flags);
if (IS_ERR(file)) { if (IS_ERR(file)) {
@ -1573,17 +1576,26 @@ retry:
accept->file_slot); accept->file_slot);
} }
cflags = 0;
if (!arg.is_empty)
cflags |= IORING_CQE_F_SOCK_NONEMPTY;
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
io_req_set_res(req, ret, 0); io_req_set_res(req, ret, cflags);
return IOU_OK; return IOU_OK;
} }
if (ret < 0) if (ret < 0)
return ret; return ret;
if (io_req_post_cqe(req, ret, IORING_CQE_F_MORE)) 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; 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; return IOU_STOP_MULTISHOT;
} }