From b3a9e0be436960072ddf327d9d82f50ee2f620e0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Tue, 22 May 2018 09:34:59 +0200 Subject: xsk: remove explicit ring structure from uapi MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In this commit we remove the explicit ring structure from the the uapi. It is tricky for an uapi to depend on a certain L1 cache line size, since it can differ for variants of the same architecture. Now, we let the user application determine the offsets of the producer, consumer and descriptors by asking the socket via getsockopt. A typical flow would be (Rx ring): struct xdp_mmap_offsets off; struct xdp_desc *ring; u32 *prod, *cons; void *map; ... getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen); map = mmap(NULL, off.rx.desc + NUM_DESCS * sizeof(struct xdp_desc), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, sfd, XDP_PGOFF_RX_RING); prod = map + off.rx.producer; cons = map + off.rx.consumer; ring = map + off.rx.desc; Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'net/xdp/xsk.c') diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 29707354cf78..378dd9287da5 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -489,6 +489,35 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname, return 0; } + case XDP_MMAP_OFFSETS: + { + struct xdp_mmap_offsets off; + + if (len < sizeof(off)) + return -EINVAL; + + off.rx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer); + off.rx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer); + off.rx.desc = offsetof(struct xdp_rxtx_ring, desc); + off.tx.producer = offsetof(struct xdp_rxtx_ring, ptrs.producer); + off.tx.consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer); + off.tx.desc = offsetof(struct xdp_rxtx_ring, desc); + + off.fr.producer = offsetof(struct xdp_umem_ring, ptrs.producer); + off.fr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer); + off.fr.desc = offsetof(struct xdp_umem_ring, desc); + off.cr.producer = offsetof(struct xdp_umem_ring, ptrs.producer); + off.cr.consumer = offsetof(struct xdp_umem_ring, ptrs.consumer); + off.cr.desc = offsetof(struct xdp_umem_ring, desc); + + len = sizeof(off); + if (copy_to_user(optval, &off, len)) + return -EFAULT; + if (put_user(len, optlen)) + return -EFAULT; + + return 0; + } default: break; } -- cgit v1.2.3