Commit a05d1f62 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring/net: support bundles for send 



If IORING_OP_SEND is used with provided buffers, the caller may also
set IORING_RECVSEND_BUNDLE to turn it into a multi-buffer send. The idea
is that an application can fill outgoing buffers in a provided buffer
group, and then arm a single send that will service them all. Once
there are no more buffers to send, or if the requested length has
been sent, the request posts a single completion for all the buffers.

This only enables it for IORING_OP_SEND, IORING_OP_SENDMSG is coming
in a separate patch. However, this patch does do a lot of the prep
work that makes wiring up the sendmsg variant pretty trivial. They
share the prep side.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 35c8711c

include/uapi/linux/io_uring.h

+9 −0
Original line number Diff line number Diff line
@@ -351,11 +351,20 @@ enum io_uring_op { 
 *				0 is reported if zerocopy was actually possible.

 *				IORING_NOTIF_USAGE_ZC_COPIED if data was copied

 *				(at least partially).

 *

 * IORING_RECVSEND_BUNDLE	Used with IOSQE_BUFFER_SELECT. If set, send will

 *				grab as many buffers from the buffer group ID

 *				given and send them all. The completion result

 *				will be the number of buffers send, with the

 *				starting buffer ID in cqe->flags as per usual

 *				for provided buffer usage. The buffers will be

 *				contigious from the starting buffer ID.

 */

#define IORING_RECVSEND_POLL_FIRST	(1U << 0)

#define IORING_RECV_MULTISHOT		(1U << 1)

#define IORING_RECVSEND_FIXED_BUF	(1U << 2)

#define IORING_SEND_ZC_REPORT_USAGE	(1U << 3)

#define IORING_RECVSEND_BUNDLE		(1U << 4)



/*

 * cqe.res for IORING_CQE_F_NOTIF if

io_uring/net.c

+128 −17
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ struct io_sr_msg { 
		struct user_msghdr __user	*umsg;

		void __user			*buf;

	};

	unsigned			len;

	int				len;

	unsigned			done_io;

	unsigned			msg_flags;

	unsigned			nr_multishot_loops;
@@ -389,6 +389,8 @@ static int io_sendmsg_prep_setup(struct io_kiocb *req, int is_msg) 
	return ret;

}



#define SENDMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_BUNDLE)



int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
@@ -407,11 +409,20 @@ int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));

	sr->len = READ_ONCE(sqe->len);

	sr->flags = READ_ONCE(sqe->ioprio);

	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)

	if (sr->flags & ~SENDMSG_FLAGS)

		return -EINVAL;

	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;

	if (sr->msg_flags & MSG_DONTWAIT)

		req->flags |= REQ_F_NOWAIT;

	if (sr->flags & IORING_RECVSEND_BUNDLE) {

		if (req->opcode == IORING_OP_SENDMSG)

			return -EINVAL;

		if (!(req->flags & REQ_F_BUFFER_SELECT))

			return -EINVAL;

		sr->msg_flags |= MSG_WAITALL;

		sr->buf_group = req->buf_index;

		req->buf_list = NULL;

	}



#ifdef CONFIG_COMPAT

	if (req->ctx->compat)
@@ -427,6 +438,79 @@ static void io_req_msg_cleanup(struct io_kiocb *req, 
	io_netmsg_recycle(req, issue_flags);

}



/*

 * For bundle completions, we need to figure out how many segments we consumed.

 * A bundle could be using a single ITER_UBUF if that's all we mapped, or it

 * could be using an ITER_IOVEC. If the latter, then if we consumed all of

 * the segments, then it's a trivial questiont o answer. If we have residual

 * data in the iter, then loop the segments to figure out how much we

 * transferred.

 */

static int io_bundle_nbufs(struct io_async_msghdr *kmsg, int ret)

{

	struct iovec *iov;

	int nbufs;



	/* no data is always zero segments, and a ubuf is always 1 segment */

	if (ret <= 0)

		return 0;

	if (iter_is_ubuf(&kmsg->msg.msg_iter))

		return 1;



	iov = kmsg->free_iov;

	if (!iov)

		iov = &kmsg->fast_iov;



	/* if all data was transferred, it's basic pointer math */

	if (!iov_iter_count(&kmsg->msg.msg_iter))

		return iter_iov(&kmsg->msg.msg_iter) - iov;



	/* short transfer, count segments */

	nbufs = 0;

	do {

		int this_len = min_t(int, iov[nbufs].iov_len, ret);



		nbufs++;

		ret -= this_len;

	} while (ret);



	return nbufs;

}



static inline bool io_send_finish(struct io_kiocb *req, int *ret,

				  struct io_async_msghdr *kmsg,

				  unsigned issue_flags)

{

	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);

	bool bundle_finished = *ret <= 0;

	unsigned int cflags;



	if (!(sr->flags & IORING_RECVSEND_BUNDLE)) {

		cflags = io_put_kbuf(req, issue_flags);

		goto finish;

	}



	cflags = io_put_kbufs(req, io_bundle_nbufs(kmsg, *ret), issue_flags);



	if (bundle_finished || req->flags & REQ_F_BL_EMPTY)

		goto finish;



	/*

	 * Fill CQE for this receive and see if we should keep trying to

	 * receive from this socket.

	 */

	if (io_req_post_cqe(req, *ret, cflags | IORING_CQE_F_MORE)) {

		io_mshot_prep_retry(req, kmsg);

		return false;

	}



	/* Otherwise stop bundle and use the current result. */

finish:

	io_req_set_res(req, *ret, cflags);

	*ret = IOU_OK;

	return true;

}



int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)

{

	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
@@ -482,7 +566,6 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags) 
	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);

	struct io_async_msghdr *kmsg = req->async_data;

	struct socket *sock;

	unsigned int cflags;

	unsigned flags;

	int min_ret = 0;

	int ret;
@@ -495,21 +578,47 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags) 
	    (sr->flags & IORING_RECVSEND_POLL_FIRST))

		return -EAGAIN;



	flags = sr->msg_flags;

	if (issue_flags & IO_URING_F_NONBLOCK)

		flags |= MSG_DONTWAIT;



retry_bundle:

	if (io_do_buffer_select(req)) {

		size_t len = sr->len;

		void __user *buf;

		struct buf_sel_arg arg = {

			.iovs = &kmsg->fast_iov,

			.max_len = min_not_zero(sr->len, INT_MAX),

			.nr_iovs = 1,

			.mode = KBUF_MODE_EXPAND,

		};



		buf = io_buffer_select(req, &len, issue_flags);

		if (unlikely(!buf))

			return -ENOBUFS;

		sr->buf = buf;

		sr->len = len;

		if (kmsg->free_iov) {

			arg.nr_iovs = kmsg->free_iov_nr;

			arg.iovs = kmsg->free_iov;

			arg.mode |= KBUF_MODE_FREE;

		}



	flags = sr->msg_flags;

	if (issue_flags & IO_URING_F_NONBLOCK)

		flags |= MSG_DONTWAIT;

	if (flags & MSG_WAITALL)

		if (!(sr->flags & IORING_RECVSEND_BUNDLE))

			arg.nr_iovs = 1;



		ret = io_buffers_select(req, &arg, issue_flags);

		if (unlikely(ret < 0))

			return ret;



		sr->len = arg.out_len;

		iov_iter_init(&kmsg->msg.msg_iter, ITER_SOURCE, arg.iovs, ret,

				arg.out_len);

		if (arg.iovs != &kmsg->fast_iov && arg.iovs != kmsg->free_iov) {

			kmsg->free_iov_nr = ret;

			kmsg->free_iov = arg.iovs;

		}

	}



	/*

	 * If MSG_WAITALL is set, or this is a bundle send, then we need

	 * the full amount. If just bundle is set, if we do a short send

	 * then we complete the bundle sequence rather than continue on.

	 */

	if (flags & MSG_WAITALL || sr->flags & IORING_RECVSEND_BUNDLE)

		min_ret = iov_iter_count(&kmsg->msg.msg_iter);



	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
@@ -534,10 +643,12 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags) 
		ret += sr->done_io;

	else if (sr->done_io)

		ret = sr->done_io;



	if (!io_send_finish(req, &ret, kmsg, issue_flags))

		goto retry_bundle;



	io_req_msg_cleanup(req, issue_flags);

	cflags = io_put_kbuf(req, issue_flags);

	io_req_set_res(req, ret, cflags);

	return IOU_OK;

	return ret;

}



static int io_recvmsg_mshot_prep(struct io_kiocb *req,