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Mon, 03 Nov 2025 15:41:34 -0800 (PST) Received: from localhost ([2a03:2880:12ff:3::]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-3dff6f625b7sm529407fac.15.2025.11.03.15.41.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Nov 2025 15:41:34 -0800 (PST) From: David Wei To: io-uring@vger.kernel.org, netdev@vger.kernel.org Cc: Jens Axboe , Pavel Begunkov Subject: [PATCH v4 12/12] io_uring/zcrx: share an ifq between rings Date: Mon, 3 Nov 2025 15:41:10 -0800 Message-ID: <20251103234110.127790-13-dw@davidwei.uk> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251103234110.127790-1-dw@davidwei.uk> References: <20251103234110.127790-1-dw@davidwei.uk> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a way to share an ifq from a src ring that is real (i.e. bound to a HW RX queue) with other rings. This is done by passing a new flag IORING_ZCRX_IFQ_REG_IMPORT in the registration struct io_uring_zcrx_ifq_reg, alongside the fd of an exported zcrx ifq. Signed-off-by: David Wei --- include/uapi/linux/io_uring.h | 4 +++ io_uring/zcrx.c | 63 +++++++++++++++++++++++++++++++++-- 2 files changed, 65 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 34bd32402902..0ead7f6b2094 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -1063,6 +1063,10 @@ struct io_uring_zcrx_area_reg { __u64 __resv2[2]; }; +enum io_uring_zcrx_ifq_reg_flags { + IORING_ZCRX_IFQ_REG_IMPORT = 1, +}; + /* * Argument for IORING_REGISTER_ZCRX_IFQ */ diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c index 17ce49536f41..5a0af9dd6a8e 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -625,6 +625,11 @@ static int export_zcrx(struct io_ring_ctx *ctx, struct io_zcrx_ifq *ifq, struct file *file; int fd = -1; + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) + return -EINVAL; + if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED))) + return -EINVAL; + if (!mem_is_zero(&ctrl->resv, sizeof(ctrl->resv))) return -EINVAL; fd = get_unused_fd_flags(O_CLOEXEC); @@ -646,6 +651,58 @@ static int export_zcrx(struct io_ring_ctx *ctx, struct io_zcrx_ifq *ifq, return fd; } +static int import_zcrx(struct io_ring_ctx *ctx, + struct io_uring_zcrx_ifq_reg __user *arg, + struct io_uring_zcrx_ifq_reg *reg) +{ + struct io_zcrx_ifq *ifq; + struct file *file; + int fd, ret; + u32 id; + + if (reg->if_rxq || reg->rq_entries || reg->area_ptr || reg->region_ptr) + return -EINVAL; + + fd = reg->if_idx; + CLASS(fd, f)(fd); + if (fd_empty(f)) + return -EBADF; + + file = fd_file(f); + if (file->f_op != &zcrx_box_fops || !file->private_data) + return -EBADF; + + ifq = file->private_data; + refcount_inc(&ifq->refs); + refcount_inc(&ifq->user_refs); + + scoped_guard(mutex, &ctx->mmap_lock) { + ret = xa_alloc(&ctx->zcrx_ctxs, &id, NULL, xa_limit_31b, GFP_KERNEL); + if (ret) + goto err; + } + + reg->zcrx_id = id; + if (copy_to_user(arg, reg, sizeof(*reg))) { + ret = -EFAULT; + goto err_xa_erase; + } + + scoped_guard(mutex, &ctx->mmap_lock) { + ret = -ENOMEM; + if (xa_store(&ctx->zcrx_ctxs, id, ifq, GFP_KERNEL)) + goto err_xa_erase; + } + + return 0; +err_xa_erase: + scoped_guard(mutex, &ctx->mmap_lock) + xa_erase(&ctx->zcrx_ctxs, id); +err: + zcrx_unregister(ifq); + return ret; +} + int io_zcrx_ctrl(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct zcrx_ctrl ctrl; @@ -695,11 +752,13 @@ int io_register_zcrx_ifq(struct io_ring_ctx *ctx, return -EINVAL; if (copy_from_user(®, arg, sizeof(reg))) return -EFAULT; - if (copy_from_user(&rd, u64_to_user_ptr(reg.region_ptr), sizeof(rd))) - return -EFAULT; if (!mem_is_zero(®.__resv, sizeof(reg.__resv)) || reg.__resv2 || reg.zcrx_id) return -EINVAL; + if (reg.flags & IORING_ZCRX_IFQ_REG_IMPORT) + return import_zcrx(ctx, arg, ®); + if (copy_from_user(&rd, u64_to_user_ptr(reg.region_ptr), sizeof(rd))) + return -EFAULT; if (reg.if_rxq == -1 || !reg.rq_entries || reg.flags) return -EINVAL; if (reg.rq_entries > IO_RQ_MAX_ENTRIES) { -- 2.47.3