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From: Jens Axboe <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], Jens Axboe <[email protected]>,
	Norman Maurer <[email protected]>
Subject: [PATCH 4/4] io_uring/net: wire up IORING_CQE_F_SOCK_NONEMPTY for accept
Date: Thu,  9 May 2024 12:00:29 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

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 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 io_uring/net.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/io_uring/net.c b/io_uring/net.c
index d4d1fc93635c..0a48596429d9 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -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 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
 		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 @@ int io_accept(struct io_kiocb *req, unsigned int issue_flags)
 						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;
 }
 
-- 
2.43.0


  parent reply	other threads:[~2024-05-09 18:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-09 18:00 [PATCHSET RFC 0/4] Propagate back queue status on accept Jens Axboe
2024-05-09 18:00 ` [PATCH 1/4] net: change proto and proto_ops accept type Jens Axboe
2024-05-09 18:00 ` [PATCH 2/4] net: have do_accept() take a struct proto_accept_arg argument Jens Axboe
2024-05-09 18:00 ` [PATCH 3/4] net: pass back whether socket was empty post accept Jens Axboe
2024-05-09 18:00 ` Jens Axboe [this message]
2024-05-14  0:13 ` [PATCHSET RFC 0/4] Propagate back queue status on accept Jakub Kicinski
2024-05-14  0:24   ` Jens Axboe

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