| Message ID | 20220628150228.1379645-9-dylany@fb.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: multishot recv | expand |
On 6/28/22 9:02 AM, Dylan Yudaken wrote: > @@ -399,13 +401,22 @@ int io_recvmsg_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->addr2); > - if (sr->flags & ~IORING_RECVSEND_POLL_FIRST) > + if (sr->flags & ~(RECVMSG_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->msg_flags & MSG_ERRQUEUE) > req->flags |= REQ_F_CLEAR_POLLIN; > + if (sr->flags & IORING_RECV_MULTISHOT) { > + if (!(req->flags & REQ_F_BUFFER_SELECT)) > + return -EINVAL; > + if (sr->msg_flags & MSG_WAITALL) > + return -EINVAL; > + if (req->opcode == IORING_OP_RECV && sr->len) > + return -EINVAL; > + req->flags |= REQ_F_APOLL_MULTISHOT; > + } Do we want to forbid not using provided buffers? If you have a ping-pong type setup, eg you know you'll have to send something before you receive anything again, seems like it'd be feasible to use this with a normal buffer? I strongly suspect that most use cases will use provided buffers for this, just wondering if there are any particular reasons for forbidding it explicitly. > > #ifdef CONFIG_COMPAT > if (req->ctx->compat) > @@ -415,6 +426,14 @@ int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) > return 0; > } > > +static inline void io_recv_prep_retry(struct io_kiocb *req) > +{ > + struct io_sr_msg *sr = io_kiocb_to_cmd(req); > + > + sr->done_io = 0; > + sr->len = 0; /* get from the provided buffer */ > +} > + > int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > { > struct io_sr_msg *sr = io_kiocb_to_cmd(req); > @@ -424,6 +443,7 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > unsigned flags; > int ret, min_ret = 0; > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > + size_t len = sr->len; > > sock = sock_from_file(req->file); > if (unlikely(!sock)) > @@ -442,16 +462,17 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > (sr->flags & IORING_RECVSEND_POLL_FIRST)) > return io_setup_async_msg(req, kmsg); > > +retry_multishot: > if (io_do_buffer_select(req)) { > void __user *buf; > > - buf = io_buffer_select(req, &sr->len, issue_flags); > + buf = io_buffer_select(req, &len, issue_flags); > if (!buf) > return -ENOBUFS; > kmsg->fast_iov[0].iov_base = buf; > - kmsg->fast_iov[0].iov_len = sr->len; > + kmsg->fast_iov[0].iov_len = len; > iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1, > - sr->len); > + len); > } > > flags = sr->msg_flags; > @@ -463,8 +484,15 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > kmsg->msg.msg_get_inq = 1; > ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg, kmsg->uaddr, flags); > if (ret < min_ret) { > - if (ret == -EAGAIN && force_nonblock) > - return io_setup_async_msg(req, kmsg); > + if (ret == -EAGAIN && force_nonblock) { > + ret = io_setup_async_msg(req, kmsg); > + if (ret == -EAGAIN && (req->flags & IO_APOLL_MULTI_POLLED) == > + IO_APOLL_MULTI_POLLED) { > + io_kbuf_recycle(req, issue_flags); > + ret = IOU_ISSUE_SKIP_COMPLETE; > + } > + return ret; > + } > if (ret == -ERESTARTSYS) > ret = -EINTR; > if (ret > 0 && io_net_retry(sock, flags)) { > @@ -491,8 +519,24 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > cflags = io_put_kbuf(req, issue_flags); > if (kmsg->msg.msg_inq) > cflags |= IORING_CQE_F_SOCK_NONEMPTY; > + > + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { > + io_req_set_res(req, ret, cflags); > + return IOU_OK; > + } > + > + if (ret > 0) { > + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, ret, > + cflags | IORING_CQE_F_MORE)) { > + io_recv_prep_retry(req); > + goto retry_multishot; > + } else { > + ret = -ECANCELED; > + } > + } > + > io_req_set_res(req, ret, cflags); > - return IOU_OK; > + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : ret; > } Minor style, but I prefer avoiding ternaries if possible. This is much easier to read for me: if (req->flags & REQ_F_POLLED) return IOU_STOP_MULTISHOT; return ret; > @@ -505,6 +549,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) > unsigned flags; > int ret, min_ret = 0; > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > + size_t len = sr->len; > > if (!(req->flags & REQ_F_POLLED) && > (sr->flags & IORING_RECVSEND_POLL_FIRST)) > @@ -514,16 +559,17 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) > if (unlikely(!sock)) > return -ENOTSOCK; > > +retry_multishot: > if (io_do_buffer_select(req)) { > void __user *buf; > > - buf = io_buffer_select(req, &sr->len, issue_flags); > + buf = io_buffer_select(req, &len, issue_flags); > if (!buf) > return -ENOBUFS; > sr->buf = buf; > } > > - ret = import_single_range(READ, sr->buf, sr->len, &iov, &msg.msg_iter); > + ret = import_single_range(READ, sr->buf, len, &iov, &msg.msg_iter); > if (unlikely(ret)) > goto out_free; > > @@ -543,8 +589,14 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) > > ret = sock_recvmsg(sock, &msg, flags); > if (ret < min_ret) { > - if (ret == -EAGAIN && force_nonblock) > - return -EAGAIN; > + if (ret == -EAGAIN && force_nonblock) { > + if ((req->flags & IO_APOLL_MULTI_POLLED) == IO_APOLL_MULTI_POLLED) { > + io_kbuf_recycle(req, issue_flags); > + ret = IOU_ISSUE_SKIP_COMPLETE; > + } > + > + return ret; > + } Maybe: if ((req->flags & IO_APOLL_MULTI_POLLED) == IO_APOLL_MULTI_POLLED) { io_kbuf_recycle(req, issue_flags); return IOU_ISSUE_SKIP_COMPLETE; } return ret; > @@ -570,8 +622,25 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) > cflags = io_put_kbuf(req, issue_flags); > if (msg.msg_inq) > cflags |= IORING_CQE_F_SOCK_NONEMPTY; > + > + > + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { > + io_req_set_res(req, ret, cflags); > + return IOU_OK; > + } > + > + if (ret > 0) { > + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, ret, > + cflags | IORING_CQE_F_MORE)) { > + io_recv_prep_retry(req); > + goto retry_multishot; > + } else { > + ret = -ECANCELED; > + } > + } > + > io_req_set_res(req, ret, cflags); > - return IOU_OK; > + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : ret; > } Same here, and maybe this needs to be a helper so you could just do return io_recv_finish(req, ret, cflags); or something like that? It's non-trivial duplicated code.
On Tue, 2022-06-28 at 09:17 -0600, Jens Axboe wrote: > On 6/28/22 9:02 AM, Dylan Yudaken wrote: > > @@ -399,13 +401,22 @@ int io_recvmsg_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->addr2); > > - if (sr->flags & ~IORING_RECVSEND_POLL_FIRST) > > + if (sr->flags & ~(RECVMSG_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->msg_flags & MSG_ERRQUEUE) > > req->flags |= REQ_F_CLEAR_POLLIN; > > + if (sr->flags & IORING_RECV_MULTISHOT) { > > + if (!(req->flags & REQ_F_BUFFER_SELECT)) > > + return -EINVAL; > > + if (sr->msg_flags & MSG_WAITALL) > > + return -EINVAL; > > + if (req->opcode == IORING_OP_RECV && sr->len) > > + return -EINVAL; > > + req->flags |= REQ_F_APOLL_MULTISHOT; > > + } > > Do we want to forbid not using provided buffers? If you have a ping- > pong > type setup, eg you know you'll have to send something before you > receive > anything again, seems like it'd be feasible to use this with a normal > buffer? > > I strongly suspect that most use cases will use provided buffers for > this, just wondering if there are any particular reasons for > forbidding > it explicitly. My feeling is that getting the user API right without provided buffers is going to be potentially complex, and probably will overlap with the MSG_WAITALL case. Expanding it later is easy but without an actual use case I think leaving it as provided buffers only for now makes sense (as you say, this is by far the most likely usecase). > > > > > #ifdef CONFIG_COMPAT > > if (req->ctx->compat) > > @@ -415,6 +426,14 @@ int io_recvmsg_prep(struct io_kiocb *req, > > const struct io_uring_sqe *sqe) > > return 0; > > } > > > > +static inline void io_recv_prep_retry(struct io_kiocb *req) > > +{ > > + struct io_sr_msg *sr = io_kiocb_to_cmd(req); > > + > > + sr->done_io = 0; > > + sr->len = 0; /* get from the provided buffer */ > > +} > > + > > int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) > > { > > struct io_sr_msg *sr = io_kiocb_to_cmd(req); > > @@ -424,6 +443,7 @@ int io_recvmsg(struct io_kiocb *req, unsigned > > int issue_flags) > > unsigned flags; > > int ret, min_ret = 0; > > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > > + size_t len = sr->len; > > > > sock = sock_from_file(req->file); > > if (unlikely(!sock)) > > @@ -442,16 +462,17 @@ int io_recvmsg(struct io_kiocb *req, unsigned > > int issue_flags) > > (sr->flags & IORING_RECVSEND_POLL_FIRST)) > > return io_setup_async_msg(req, kmsg); > > > > +retry_multishot: > > if (io_do_buffer_select(req)) { > > void __user *buf; > > > > - buf = io_buffer_select(req, &sr->len, issue_flags); > > + buf = io_buffer_select(req, &len, issue_flags); > > if (!buf) > > return -ENOBUFS; > > kmsg->fast_iov[0].iov_base = buf; > > - kmsg->fast_iov[0].iov_len = sr->len; > > + kmsg->fast_iov[0].iov_len = len; > > iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg- > > >fast_iov, 1, > > - sr->len); > > + len); > > } > > > > flags = sr->msg_flags; > > @@ -463,8 +484,15 @@ int io_recvmsg(struct io_kiocb *req, unsigned > > int issue_flags) > > kmsg->msg.msg_get_inq = 1; > > ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg, kmsg- > > >uaddr, flags); > > if (ret < min_ret) { > > - if (ret == -EAGAIN && force_nonblock) > > - return io_setup_async_msg(req, kmsg); > > + if (ret == -EAGAIN && force_nonblock) { > > + ret = io_setup_async_msg(req, kmsg); > > + if (ret == -EAGAIN && (req->flags & > > IO_APOLL_MULTI_POLLED) == > > + > > IO_APOLL_MULTI_POLLED) { > > + io_kbuf_recycle(req, issue_flags); > > + ret = IOU_ISSUE_SKIP_COMPLETE; > > + } > > + return ret; > > + } > > if (ret == -ERESTARTSYS) > > ret = -EINTR; > > if (ret > 0 && io_net_retry(sock, flags)) { > > @@ -491,8 +519,24 @@ int io_recvmsg(struct io_kiocb *req, unsigned > > int issue_flags) > > cflags = io_put_kbuf(req, issue_flags); > > if (kmsg->msg.msg_inq) > > cflags |= IORING_CQE_F_SOCK_NONEMPTY; > > + > > + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { > > + io_req_set_res(req, ret, cflags); > > + return IOU_OK; > > + } > > + > > + if (ret > 0) { > > + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, > > ret, > > + cflags | IORING_CQE_F_MORE)) { > > + io_recv_prep_retry(req); > > + goto retry_multishot; > > + } else { > > + ret = -ECANCELED; > > + } > > + } > > + > > io_req_set_res(req, ret, cflags); > > - return IOU_OK; > > + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : > > ret; > > } > > Minor style, but I prefer avoiding ternaries if possible. This is > much > easier to read for me: > > if (req->flags & REQ_F_POLLED) > return IOU_STOP_MULTISHOT; > return ret; OK > > > @@ -505,6 +549,7 @@ int io_recv(struct io_kiocb *req, unsigned int > > issue_flags) > > unsigned flags; > > int ret, min_ret = 0; > > bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; > > + size_t len = sr->len; > > > > if (!(req->flags & REQ_F_POLLED) && > > (sr->flags & IORING_RECVSEND_POLL_FIRST)) > > @@ -514,16 +559,17 @@ int io_recv(struct io_kiocb *req, unsigned > > int issue_flags) > > if (unlikely(!sock)) > > return -ENOTSOCK; > > > > +retry_multishot: > > if (io_do_buffer_select(req)) { > > void __user *buf; > > > > - buf = io_buffer_select(req, &sr->len, issue_flags); > > + buf = io_buffer_select(req, &len, issue_flags); > > if (!buf) > > return -ENOBUFS; > > sr->buf = buf; > > } > > > > - ret = import_single_range(READ, sr->buf, sr->len, &iov, > > &msg.msg_iter); > > + ret = import_single_range(READ, sr->buf, len, &iov, > > &msg.msg_iter); > > if (unlikely(ret)) > > goto out_free; > > > > @@ -543,8 +589,14 @@ int io_recv(struct io_kiocb *req, unsigned int > > issue_flags) > > > > ret = sock_recvmsg(sock, &msg, flags); > > if (ret < min_ret) { > > - if (ret == -EAGAIN && force_nonblock) > > - return -EAGAIN; > > + if (ret == -EAGAIN && force_nonblock) { > > + if ((req->flags & IO_APOLL_MULTI_POLLED) == > > IO_APOLL_MULTI_POLLED) { > > + io_kbuf_recycle(req, issue_flags); > > + ret = IOU_ISSUE_SKIP_COMPLETE; > > + } > > + > > + return ret; > > + } > > Maybe: > if ((req->flags & IO_APOLL_MULTI_POLLED) == > IO_APOLL_MULTI_POLLED) { > io_kbuf_recycle(req, issue_flags); > return IOU_ISSUE_SKIP_COMPLETE; > } > > return ret; > > > @@ -570,8 +622,25 @@ int io_recv(struct io_kiocb *req, unsigned int > > issue_flags) > > cflags = io_put_kbuf(req, issue_flags); > > if (msg.msg_inq) > > cflags |= IORING_CQE_F_SOCK_NONEMPTY; > > + > > + > > + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { > > + io_req_set_res(req, ret, cflags); > > + return IOU_OK; > > + } > > + > > + if (ret > 0) { > > + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, > > ret, > > + cflags | IORING_CQE_F_MORE)) { > > + io_recv_prep_retry(req); > > + goto retry_multishot; > > + } else { > > + ret = -ECANCELED; > > + } > > + } > > + > > io_req_set_res(req, ret, cflags); > > - return IOU_OK; > > + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : > > ret; > > } > > Same here, and maybe this needs to be a helper so you could just do > > return io_recv_finish(req, ret, cflags); > > or something like that? It's non-trivial duplicated code. > Makes sense - I'll do that
diff --git a/io_uring/net.c b/io_uring/net.c index 0268c4603f5d..9bf8c6c0b549 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -389,6 +389,8 @@ int io_recvmsg_prep_async(struct io_kiocb *req) return ret; } +#define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT) + int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sr_msg *sr = io_kiocb_to_cmd(req); @@ -399,13 +401,22 @@ int io_recvmsg_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->addr2); - if (sr->flags & ~IORING_RECVSEND_POLL_FIRST) + if (sr->flags & ~(RECVMSG_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->msg_flags & MSG_ERRQUEUE) req->flags |= REQ_F_CLEAR_POLLIN; + if (sr->flags & IORING_RECV_MULTISHOT) { + if (!(req->flags & REQ_F_BUFFER_SELECT)) + return -EINVAL; + if (sr->msg_flags & MSG_WAITALL) + return -EINVAL; + if (req->opcode == IORING_OP_RECV && sr->len) + return -EINVAL; + req->flags |= REQ_F_APOLL_MULTISHOT; + } #ifdef CONFIG_COMPAT if (req->ctx->compat) @@ -415,6 +426,14 @@ int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) return 0; } +static inline void io_recv_prep_retry(struct io_kiocb *req) +{ + struct io_sr_msg *sr = io_kiocb_to_cmd(req); + + sr->done_io = 0; + sr->len = 0; /* get from the provided buffer */ +} + int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_sr_msg *sr = io_kiocb_to_cmd(req); @@ -424,6 +443,7 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) unsigned flags; int ret, min_ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; + size_t len = sr->len; sock = sock_from_file(req->file); if (unlikely(!sock)) @@ -442,16 +462,17 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) (sr->flags & IORING_RECVSEND_POLL_FIRST)) return io_setup_async_msg(req, kmsg); +retry_multishot: if (io_do_buffer_select(req)) { void __user *buf; - buf = io_buffer_select(req, &sr->len, issue_flags); + buf = io_buffer_select(req, &len, issue_flags); if (!buf) return -ENOBUFS; kmsg->fast_iov[0].iov_base = buf; - kmsg->fast_iov[0].iov_len = sr->len; + kmsg->fast_iov[0].iov_len = len; iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1, - sr->len); + len); } flags = sr->msg_flags; @@ -463,8 +484,15 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) kmsg->msg.msg_get_inq = 1; ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg, kmsg->uaddr, flags); if (ret < min_ret) { - if (ret == -EAGAIN && force_nonblock) - return io_setup_async_msg(req, kmsg); + if (ret == -EAGAIN && force_nonblock) { + ret = io_setup_async_msg(req, kmsg); + if (ret == -EAGAIN && (req->flags & IO_APOLL_MULTI_POLLED) == + IO_APOLL_MULTI_POLLED) { + io_kbuf_recycle(req, issue_flags); + ret = IOU_ISSUE_SKIP_COMPLETE; + } + return ret; + } if (ret == -ERESTARTSYS) ret = -EINTR; if (ret > 0 && io_net_retry(sock, flags)) { @@ -491,8 +519,24 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) cflags = io_put_kbuf(req, issue_flags); if (kmsg->msg.msg_inq) cflags |= IORING_CQE_F_SOCK_NONEMPTY; + + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { + io_req_set_res(req, ret, cflags); + return IOU_OK; + } + + if (ret > 0) { + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, ret, + cflags | IORING_CQE_F_MORE)) { + io_recv_prep_retry(req); + goto retry_multishot; + } else { + ret = -ECANCELED; + } + } + io_req_set_res(req, ret, cflags); - return IOU_OK; + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : ret; } int io_recv(struct io_kiocb *req, unsigned int issue_flags) @@ -505,6 +549,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) unsigned flags; int ret, min_ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; + size_t len = sr->len; if (!(req->flags & REQ_F_POLLED) && (sr->flags & IORING_RECVSEND_POLL_FIRST)) @@ -514,16 +559,17 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) if (unlikely(!sock)) return -ENOTSOCK; +retry_multishot: if (io_do_buffer_select(req)) { void __user *buf; - buf = io_buffer_select(req, &sr->len, issue_flags); + buf = io_buffer_select(req, &len, issue_flags); if (!buf) return -ENOBUFS; sr->buf = buf; } - ret = import_single_range(READ, sr->buf, sr->len, &iov, &msg.msg_iter); + ret = import_single_range(READ, sr->buf, len, &iov, &msg.msg_iter); if (unlikely(ret)) goto out_free; @@ -543,8 +589,14 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) ret = sock_recvmsg(sock, &msg, flags); if (ret < min_ret) { - if (ret == -EAGAIN && force_nonblock) - return -EAGAIN; + if (ret == -EAGAIN && force_nonblock) { + if ((req->flags & IO_APOLL_MULTI_POLLED) == IO_APOLL_MULTI_POLLED) { + io_kbuf_recycle(req, issue_flags); + ret = IOU_ISSUE_SKIP_COMPLETE; + } + + return ret; + } if (ret == -ERESTARTSYS) ret = -EINTR; if (ret > 0 && io_net_retry(sock, flags)) { @@ -570,8 +622,25 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags) cflags = io_put_kbuf(req, issue_flags); if (msg.msg_inq) cflags |= IORING_CQE_F_SOCK_NONEMPTY; + + + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { + io_req_set_res(req, ret, cflags); + return IOU_OK; + } + + if (ret > 0) { + if (io_post_aux_cqe(req->ctx, req->cqe.user_data, ret, + cflags | IORING_CQE_F_MORE)) { + io_recv_prep_retry(req); + goto retry_multishot; + } else { + ret = -ECANCELED; + } + } + io_req_set_res(req, ret, cflags); - return IOU_OK; + return req->flags & REQ_F_POLLED ? IOU_STOP_MULTISHOT : ret; } int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
Support multishot receive for io_uring. Typical server applications will run a loop where for each recv CQE it requeues another recv/recvmsg. This can be simplified by using the existing multishot functionality combined with io_uring's provided buffers. The API is to add the IORING_RECV_MULTISHOT flag to the SQE. CQEs will then be posted (with IORING_CQE_F_MORE flag set) when data is available and is read. Once an error occurs or the socket ends, the multishot will be removed and a completion without IORING_CQE_F_MORE will be posted. The benefit to this is that the recv is much more performant. * Subsequent receives are queued up straight away without requiring the application to finish a processing loop. * If there are more data in the socket (sat the provided buffer size is smaller than the socket buffer) then the data is immediately returned, improving batching. * Poll is only armed once and reused, saving CPU cycles Signed-off-by: Dylan Yudaken <dylany@fb.com> --- io_uring/net.c | 93 +++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 81 insertions(+), 12 deletions(-)