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authorBjörn Töpel <bjorn.topel@intel.com>2018-05-22 09:34:59 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2018-05-22 10:25:06 +0200
commitb3a9e0be436960072ddf327d9d82f50ee2f620e0 (patch)
tree40260bda517d9f1e16ee3f529a0bbc50df495be7 /net/xdp
parent2e59dd5e4f6e884d1f7a70acf9845d223429026e (diff)
downloadlinux-stericsson-b3a9e0be436960072ddf327d9d82f50ee2f620e0.tar.gz
xsk: remove explicit ring structure from uapi
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 <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/xdp')
-rw-r--r--net/xdp/xsk.c29
-rw-r--r--net/xdp/xsk_queue.h17
2 files changed, 46 insertions, 0 deletions
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;
}
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 62e43be407d8..cb8e5be35110 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -13,6 +13,23 @@
#define RX_BATCH_SIZE 16
+struct xdp_ring {
+ u32 producer ____cacheline_aligned_in_smp;
+ u32 consumer ____cacheline_aligned_in_smp;
+};
+
+/* Used for the RX and TX queues for packets */
+struct xdp_rxtx_ring {
+ struct xdp_ring ptrs;
+ struct xdp_desc desc[0] ____cacheline_aligned_in_smp;
+};
+
+/* Used for the fill and completion queues for buffers */
+struct xdp_umem_ring {
+ struct xdp_ring ptrs;
+ u32 desc[0] ____cacheline_aligned_in_smp;
+};
+
struct xsk_queue {
struct xdp_umem_props umem_props;
u32 ring_mask;