From a05d1f625c7aa681d8816bc0f10089289ad07aad Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 5 Mar 2024 13:10:04 -0700 Subject: 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: Jens Axboe --- io_uring/net.c | 145 ++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 128 insertions(+), 17 deletions(-) (limited to 'io_uring/net.c') diff --git a/io_uring/net.c b/io_uring/net.c index 13685d133582..3e326576254b 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -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, + }; + + if (kmsg->free_iov) { + arg.nr_iovs = kmsg->free_iov_nr; + arg.iovs = kmsg->free_iov; + arg.mode |= KBUF_MODE_FREE; + } - buf = io_buffer_select(req, &len, issue_flags); - if (unlikely(!buf)) - return -ENOBUFS; - sr->buf = buf; - sr->len = len; + 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; + } } - flags = sr->msg_flags; - if (issue_flags & IO_URING_F_NONBLOCK) - flags |= MSG_DONTWAIT; - if (flags & MSG_WAITALL) + /* + * 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, -- cgit v1.2.3-58-ga151