[PATCH 2/2] io_uring: add support for IORING_OP_CONNECT

[Jens Axboe <axboe@kernel.dk>]

This allows an application to call connect() in an async fashion. Like
other opcodes, we first try a non-blocking accept, then punt to async
context if we have to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c                 | 37 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/io_uring.h |  1 +
 2 files changed, 38 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0c66cd6ed0b0..5ceec1a4faad 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1968,6 +1968,40 @@ static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 #endif
 }
 
+static int io_connect(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+		      struct io_kiocb **nxt, bool force_nonblock)
+{
+#if defined(CONFIG_NET)
+	struct sockaddr __user *addr;
+	unsigned file_flags;
+	int addr_len, ret;
+
+	if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || sqe->flags)
+		return -EINVAL;
+
+	addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
+	addr_len = READ_ONCE(sqe->addr2);
+	file_flags = force_nonblock ? O_NONBLOCK : 0;
+
+	ret = __sys_connect_file(req->file, addr, addr_len, file_flags);
+	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
+		req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
+		return -EAGAIN;
+	}
+	if (ret == -ERESTARTSYS)
+		ret = -EINTR;
+	if (ret < 0 && (req->flags & REQ_F_LINK))
+		req->flags |= REQ_F_FAIL_LINK;
+	io_cqring_add_event(req, ret);
+	io_put_req_find_next(req, nxt);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
 static inline void io_poll_remove_req(struct io_kiocb *req)
 {
 	if (!RB_EMPTY_NODE(&req->rb_node)) {
@@ -2622,6 +2656,9 @@ static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt,
 	case IORING_OP_ACCEPT:
 		ret = io_accept(req, s->sqe, nxt, force_nonblock);
 		break;
+	case IORING_OP_CONNECT:
+		ret = io_connect(req, s->sqe, nxt, force_nonblock);
+		break;
 	case IORING_OP_ASYNC_CANCEL:
 		ret = io_async_cancel(req, s->sqe, nxt);
 		break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 2a1569211d87..4637ed1d9949 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -73,6 +73,7 @@ struct io_uring_sqe {
 #define IORING_OP_ACCEPT	13
 #define IORING_OP_ASYNC_CANCEL	14
 #define IORING_OP_LINK_TIMEOUT	15
+#define IORING_OP_CONNECT	16
 
 /*
  * sqe->fsync_flags
-- 
2.24.0