On 2024-12-06 08:05, Simon Horman wrote:
> On Wed, Dec 04, 2024 at 09:21:48AM -0800, David Wei wrote:
>> From: David Wei <davidhwei@xxxxxxxx>
>>
>> Add a new object called an interface queue (ifq) that represents a net
>> rx queue that has been configured for zero copy. Each ifq is registered
>> using a new registration opcode IORING_REGISTER_ZCRX_IFQ.
>>
>> The refill queue is allocated by the kernel and mapped by userspace
>> using a new offset IORING_OFF_RQ_RING, in a similar fashion to the main
>> SQ/CQ. It is used by userspace to return buffers that it is done with,
>> which will then be re-used by the netdev again.
>>
>> The main CQ ring is used to notify userspace of received data by using
>> the upper 16 bytes of a big CQE as a new struct io_uring_zcrx_cqe. Each
>> entry contains the offset + len to the data.
>>
>> For now, each io_uring instance only has a single ifq.
>>
>> Signed-off-by: David Wei <dw@xxxxxxxxxxx>
>
> ...
>
>> diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
>
> ...
>
>> +int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
>> + struct io_uring_zcrx_ifq_reg __user *arg)
>> +{
>> + struct io_uring_zcrx_ifq_reg reg;
>> + struct io_uring_region_desc rd;
>> + struct io_zcrx_ifq *ifq;
>> + size_t ring_sz, rqes_sz;
>> + int ret;
>> +
>> + /*
>> + * 1. Interface queue allocation.
>> + * 2. It can observe data destined for sockets of other tasks.
>> + */
>> + if (!capable(CAP_NET_ADMIN))
>> + return -EPERM;
>> +
>> + /* mandatory io_uring features for zc rx */
>> + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
>> + ctx->flags & IORING_SETUP_CQE32))
>> + return -EINVAL;
>> + if (ctx->ifq)
>> + return -EBUSY;
>> + 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 (memchr_inv(®.__resv, 0, sizeof(reg.__resv)))
>> + return -EINVAL;
>> + if (reg.if_rxq == -1 || !reg.rq_entries || reg.flags)
>> + return -EINVAL;
>> + if (reg.rq_entries > IO_RQ_MAX_ENTRIES) {
>> + if (!(ctx->flags & IORING_SETUP_CLAMP))
>> + return -EINVAL;
>> + reg.rq_entries = IO_RQ_MAX_ENTRIES;
>> + }
>> + reg.rq_entries = roundup_pow_of_two(reg.rq_entries);
>> +
>> + if (!reg.area_ptr)
>> + return -EFAULT;
>> +
>> + ifq = io_zcrx_ifq_alloc(ctx);
>> + if (!ifq)
>> + return -ENOMEM;
>> +
>> + ret = io_allocate_rbuf_ring(ifq, ®, &rd);
>> + if (ret)
>> + goto err;
>> +
>> + ifq->rq_entries = reg.rq_entries;
>> + ifq->if_rxq = reg.if_rxq;
>> +
>> + ring_sz = sizeof(struct io_uring);
>> + rqes_sz = sizeof(struct io_uring_zcrx_rqe) * ifq->rq_entries;
>
> Hi David,
>
> A minor nit from my side: rqes_sz is set but otherwise unused in this
> function. Perhaps it can be removed?
>
> Flagged by W=1 builds.
Hi Simon, thanks for flagging this, I'll remove it in the next version.
