From 10c7d33ecd51619e453cf6aeee8e326f8ba5cfea Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Jul 2022 21:52:46 +0100 Subject: [PATCH] io_uring: sendzc with fixed buffers Allow zerocopy sends to use fixed buffers. There is an optimisation for this case, the network layer don't need to reference the pages, see SKBFL_MANAGED_FRAG_REFS, so io_uring have to ensure validity of fixed buffers until the notifier is released. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/e1d8bd1b5934e541d90c1824eb4020ae3f5f43f3.1657643355.git.asml.silence@gmail.com [axboe: fold in 32-bit pointer cast warning fix] Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 6 +++++- io_uring/net.c | 29 ++++++++++++++++++++++++----- 2 files changed, 29 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 0736e27..f1a9ff9b 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -272,9 +272,13 @@ enum io_uring_op { * IORING_RECV_MULTISHOT Multishot recv. Sets IORING_CQE_F_MORE if * the handler will continue to report * CQEs on behalf of the same SQE. + * + * IORING_RECVSEND_FIXED_BUF Use registered buffers, the index is stored in + * the buf_index field. */ #define IORING_RECVSEND_POLL_FIRST (1U << 0) -#define IORING_RECV_MULTISHOT (1U << 1) +#define IORING_RECV_MULTISHOT (1U << 1) +#define IORING_RECVSEND_FIXED_BUF (1U << 2) /* * accept flags stored in sqe->ioprio diff --git a/io_uring/net.c b/io_uring/net.c index 61414d8..ab443c52 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -15,6 +15,7 @@ #include "alloc_cache.h" #include "net.h" #include "notif.h" +#include "rsrc.h" #if defined(CONFIG_NET) struct io_shutdown { @@ -849,13 +850,23 @@ out_free: int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sendzc *zc = io_kiocb_to_cmd(req); + struct io_ring_ctx *ctx = req->ctx; if (READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)) return -EINVAL; zc->flags = READ_ONCE(sqe->ioprio); - if (zc->flags & ~IORING_RECVSEND_POLL_FIRST) + if (zc->flags & ~(IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)) return -EINVAL; + if (zc->flags & IORING_RECVSEND_FIXED_BUF) { + unsigned idx = READ_ONCE(sqe->buf_index); + + if (unlikely(idx >= ctx->nr_user_bufs)) + return -EFAULT; + idx = array_index_nospec(idx, ctx->nr_user_bufs); + req->imu = READ_ONCE(ctx->user_bufs[idx]); + io_req_set_rsrc_node(req, ctx, 0); + } zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr)); zc->len = READ_ONCE(sqe->len); @@ -909,10 +920,18 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags) msg.msg_controllen = 0; msg.msg_namelen = 0; - ret = import_single_range(WRITE, zc->buf, zc->len, &iov, &msg.msg_iter); - if (unlikely(ret)) - return ret; - mm_account_pinned_pages(¬if->uarg.mmp, zc->len); + if (zc->flags & IORING_RECVSEND_FIXED_BUF) { + ret = io_import_fixed(WRITE, &msg.msg_iter, req->imu, + (u64)(uintptr_t)zc->buf, zc->len); + if (unlikely(ret)) + return ret; + } else { + ret = import_single_range(WRITE, zc->buf, zc->len, &iov, + &msg.msg_iter); + if (unlikely(ret)) + return ret; + mm_account_pinned_pages(¬if->uarg.mmp, zc->len); + } if (zc->addr) { ret = move_addr_to_kernel(zc->addr, zc->addr_len, &address); -- 2.7.4