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;
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| @@ -23,13 +23,27 @@ struct sockaddr_xdp { · 22 unmodified lines | |||
| 23 | __u32 sxdp_shared_umem_fd; | 23 | __u32 sxdp_shared_umem_fd; |
| 24 | }; | 24 | }; |
| 25 | 25 | ||
| 26 | struct xdp_ring_offset { | ||
| 27 | __u64 producer; | ||
| 28 | __u64 consumer; | ||
| 29 | __u64 desc; | ||
| 30 | }; | ||
| 31 | |||
| 32 | struct xdp_mmap_offsets { | ||
| 33 | struct xdp_ring_offset rx; | ||
| 34 | struct xdp_ring_offset tx; | ||
| 35 | struct xdp_ring_offset fr; /* Fill */ | ||
| 36 | struct xdp_ring_offset cr; /* Completion */ | ||
| 37 | }; | ||
| 38 | |||
| 26 | /* XDP socket options */ | 39 | /* XDP socket options */ |
| 27 | #define XDP_RX_RING 1 | 40 | #define XDP_MMAP_OFFSETS 1 |
| 28 | #define XDP_TX_RING 2 | 41 | #define XDP_RX_RING 2 |
| 29 | #define XDP_UMEM_REG 3 | 42 | #define XDP_TX_RING 3 |
| 30 | #define XDP_UMEM_FILL_RING 4 | 43 | #define XDP_UMEM_REG 4 |
| 31 | #define XDP_UMEM_COMPLETION_RING 5 | 44 | #define XDP_UMEM_FILL_RING 5 |
| 32 | #define XDP_STATISTICS 6 | 45 | #define XDP_UMEM_COMPLETION_RING 6 |
| 46 | #define XDP_STATISTICS 7 | ||
| 33 | 47 | ||
| 34 | struct xdp_umem_reg { | 48 | struct xdp_umem_reg { |
| 35 | __u64 addr; /* Start of packet data area */ | 49 | __u64 addr; /* Start of packet data area */ |
| @@ -50,6 +64,7 @@ struct xdp_statistics { · 14 unmodified lines | |||
| 50 | #define XDP_UMEM_PGOFF_FILL_RING 0x100000000 | 64 | #define XDP_UMEM_PGOFF_FILL_RING 0x100000000 |
| 51 | #define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000 | 65 | #define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000 |
| 52 | 66 | ||
| 67 | /* Rx/Tx descriptor */ | ||
| 53 | struct xdp_desc { | 68 | struct xdp_desc { |
| 54 | __u32 idx; | 69 | __u32 idx; |
| 55 | __u32 len; | 70 | __u32 len; |
| @@ -58,21 +73,6 @@ struct xdp_desc { · 2 unmodified lines | |||
| 58 | __u8 padding[5]; | 73 | __u8 padding[5]; |
| 59 | }; | 74 | }; |
| 60 | 75 | ||
| 61 | struct xdp_ring { | 76 | /* UMEM descriptor is __u32 */ |
| 62 | __u32 producer __attribute__((aligned(64))); | ||
| 63 | __u32 consumer __attribute__((aligned(64))); | ||
| 64 | }; | ||
| 65 | |||
| 66 | /* Used for the RX and TX queues for packets */ | ||
| 67 | struct xdp_rxtx_ring { | ||
| 68 | struct xdp_ring ptrs; | ||
| 69 | struct xdp_desc desc[0] __attribute__((aligned(64))); | ||
| 70 | }; | ||
| 71 | |||
| 72 | /* Used for the fill and completion queues for buffers */ | ||
| 73 | struct xdp_umem_ring { | ||
| 74 | struct xdp_ring ptrs; | ||
| 75 | __u32 desc[0] __attribute__((aligned(64))); | ||
| 76 | }; | ||
| 77 | 77 | ||
| 78 | #endif /* _LINUX_IF_XDP_H */ | 78 | #endif /* _LINUX_IF_XDP_H */ |