[RFC PATCH v3 08/20] io_uring: add mmap support for shared ifq ringbuffers
From: David Wei <hidden>
Date: 2023-12-19 21:04:13
Also in:
io-uring
Subsystem:
io_uring, the rest · Maintainers:
Jens Axboe, Linus Torvalds
From: David Wei <redacted> This patch adds mmap support for ifq rbuf rings. There are two rings and a struct io_rbuf_ring that contains the head and tail ptrs into each ring. Just like the io_uring SQ/CQ rings, userspace issues a single mmap call using the io_uring fd w/ magic offset IORING_OFF_RBUF_RING. An opaque ptr is returned to userspace, which is then expected to use the offsets returned in the registration struct to get access to the head/tail and rings. Signed-off-by: David Wei <redacted> --- include/uapi/linux/io_uring.h | 2 ++ io_uring/io_uring.c | 5 +++++ io_uring/zc_rx.c | 19 ++++++++++++++++++- 3 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 024a6f79323b..839933e562e6 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h@@ -428,6 +428,8 @@ enum { #define IORING_OFF_PBUF_RING 0x80000000ULL #define IORING_OFF_PBUF_SHIFT 16 #define IORING_OFF_MMAP_MASK 0xf8000000ULL +#define IORING_OFF_RBUF_RING 0x20000000ULL +#define IORING_OFF_RBUF_SHIFT 16 /* * Filled with the offset for mmap(2)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7fff01d57e9e..02d6d638bd65 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c@@ -3516,6 +3516,11 @@ static void *io_uring_validate_mmap_request(struct file *file, return ERR_PTR(-EINVAL); break; } + case IORING_OFF_RBUF_RING: + if (!ctx->ifq) + return ERR_PTR(-EINVAL); + ptr = ctx->ifq->ring; + break; default: return ERR_PTR(-EINVAL); }
diff --git a/io_uring/zc_rx.c b/io_uring/zc_rx.c
index 5fc94cad5e3a..7e3e6f6d446b 100644
--- a/io_uring/zc_rx.c
+++ b/io_uring/zc_rx.c@@ -61,6 +61,7 @@ int io_register_zc_rx_ifq(struct io_ring_ctx *ctx, { struct io_uring_zc_rx_ifq_reg reg; struct io_zc_rx_ifq *ifq; + size_t ring_sz, rqes_sz, cqes_sz; int ret; if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
@@ -87,8 +88,24 @@ int io_register_zc_rx_ifq(struct io_ring_ctx *ctx, ifq->rq_entries = reg.rq_entries; ifq->cq_entries = reg.cq_entries; ifq->if_rxq_id = reg.if_rxq_id; - ctx->ifq = ifq; + ring_sz = sizeof(struct io_rbuf_ring); + rqes_sz = sizeof(struct io_uring_rbuf_rqe) * ifq->rq_entries; + cqes_sz = sizeof(struct io_uring_rbuf_cqe) * ifq->cq_entries; + reg.mmap_sz = ring_sz + rqes_sz + cqes_sz; + reg.rq_off.rqes = ring_sz; + reg.cq_off.cqes = ring_sz + rqes_sz; + reg.rq_off.head = offsetof(struct io_rbuf_ring, rq.head); + reg.rq_off.tail = offsetof(struct io_rbuf_ring, rq.tail); + reg.cq_off.head = offsetof(struct io_rbuf_ring, cq.head); + reg.cq_off.tail = offsetof(struct io_rbuf_ring, cq.tail); + + if (copy_to_user(arg, ®, sizeof(reg))) { + ret = -EFAULT; + goto err; + } + + ctx->ifq = ifq; return 0; err: io_zc_rx_ifq_free(ifq);
--
2.39.3