Commit 77698878 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

nvme-tcp: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage 



When transmitting data, call down into TCP using a sendmsg with
MSG_SPLICE_PAGES instead of sendpage.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarSagi Grimberg <sagi@grimberg.me>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
cc: Keith Busch <kbusch@kernel.org>
cc: Jens Axboe <axboe@fb.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Chaitanya Kulkarni <kch@nvidia.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: linux-nvme@lists.infradead.org
Link: https://lore.kernel.org/r/20230623225513.2732256-8-dhowells@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a1a5e875

drivers/nvme/host/tcp.c

+27 −22
Original line number Diff line number Diff line
@@ -997,25 +997,28 @@ static int nvme_tcp_try_send_data(struct nvme_tcp_request *req) 
	u32 h2cdata_left = req->h2cdata_left;



	while (true) {

		struct bio_vec bvec;

		struct msghdr msg = {

			.msg_flags = MSG_DONTWAIT | MSG_SPLICE_PAGES,

		};

		struct page *page = nvme_tcp_req_cur_page(req);

		size_t offset = nvme_tcp_req_cur_offset(req);

		size_t len = nvme_tcp_req_cur_length(req);

		bool last = nvme_tcp_pdu_last_send(req, len);

		int req_data_sent = req->data_sent;

		int ret, flags = MSG_DONTWAIT;

		int ret;



		if (last && !queue->data_digest && !nvme_tcp_queue_more(queue))

			flags |= MSG_EOR;

			msg.msg_flags |= MSG_EOR;

		else

			flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;

			msg.msg_flags |= MSG_MORE;



		if (sendpage_ok(page)) {

			ret = kernel_sendpage(queue->sock, page, offset, len,

					flags);

		} else {

			ret = sock_no_sendpage(queue->sock, page, offset, len,

					flags);

		}

		if (!sendpage_ok(page))

			msg.msg_flags &= ~MSG_SPLICE_PAGES,



		bvec_set_page(&bvec, page, len, offset);

		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len);

		ret = sock_sendmsg(queue->sock, &msg);

		if (ret <= 0)

			return ret;
@@ -1054,22 +1057,24 @@ static int nvme_tcp_try_send_cmd_pdu(struct nvme_tcp_request *req) 
{

	struct nvme_tcp_queue *queue = req->queue;

	struct nvme_tcp_cmd_pdu *pdu = nvme_tcp_req_cmd_pdu(req);

	struct bio_vec bvec;

	struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_SPLICE_PAGES, };

	bool inline_data = nvme_tcp_has_inline_data(req);

	u8 hdgst = nvme_tcp_hdgst_len(queue);

	int len = sizeof(*pdu) + hdgst - req->offset;

	int flags = MSG_DONTWAIT;

	int ret;



	if (inline_data || nvme_tcp_queue_more(queue))

		flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;

		msg.msg_flags |= MSG_MORE;

	else

		flags |= MSG_EOR;

		msg.msg_flags |= MSG_EOR;



	if (queue->hdr_digest && !req->offset)

		nvme_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));



	ret = kernel_sendpage(queue->sock, virt_to_page(pdu),

			offset_in_page(pdu) + req->offset, len,  flags);

	bvec_set_virt(&bvec, (void *)pdu + req->offset, len);

	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len);

	ret = sock_sendmsg(queue->sock, &msg);

	if (unlikely(ret <= 0))

		return ret;
@@ -1093,6 +1098,8 @@ static int nvme_tcp_try_send_data_pdu(struct nvme_tcp_request *req) 
{

	struct nvme_tcp_queue *queue = req->queue;

	struct nvme_tcp_data_pdu *pdu = nvme_tcp_req_data_pdu(req);

	struct bio_vec bvec;

	struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_MORE, };

	u8 hdgst = nvme_tcp_hdgst_len(queue);

	int len = sizeof(*pdu) - req->offset + hdgst;

	int ret;
@@ -1101,13 +1108,11 @@ static int nvme_tcp_try_send_data_pdu(struct nvme_tcp_request *req) 
		nvme_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));



	if (!req->h2cdata_left)

		ret = kernel_sendpage(queue->sock, virt_to_page(pdu),

				offset_in_page(pdu) + req->offset, len,

				MSG_DONTWAIT | MSG_MORE | MSG_SENDPAGE_NOTLAST);

	else

		ret = sock_no_sendpage(queue->sock, virt_to_page(pdu),

				offset_in_page(pdu) + req->offset, len,

				MSG_DONTWAIT | MSG_MORE);

		msg.msg_flags |= MSG_SPLICE_PAGES;



	bvec_set_virt(&bvec, (void *)pdu + req->offset, len);

	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len);

	ret = sock_sendmsg(queue->sock, &msg);

	if (unlikely(ret <= 0))

		return ret;