3 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
4 * Released under terms in GPL version 2. See COPYING.
6 #ifndef __LINUX_NET_XDP_H__
7 #define __LINUX_NET_XDP_H__
10 * DOC: XDP RX-queue information
12 * The XDP RX-queue info (xdp_rxq_info) is associated with the driver
13 * level RX-ring queues. It is information that is specific to how
14 * the driver have configured a given RX-ring queue.
16 * Each xdp_buff frame received in the driver carry a (pointer)
17 * reference to this xdp_rxq_info structure. This provides the XDP
18 * data-path read-access to RX-info for both kernel and bpf-side
21 * For now, direct access is only safe while running in NAPI/softirq
22 * context. Contents is read-mostly and must not be updated during
23 * driver NAPI/softirq poll.
25 * The driver usage API is a register and unregister API.
27 * The struct is not directly tied to the XDP prog. A new XDP prog
28 * can be attached as long as it doesn't change the underlying
29 * RX-ring. If the RX-ring does change significantly, the NIC driver
30 * naturally need to stop the RX-ring before purging and reallocating
31 * memory. In that process the driver MUST call unregistor (which
32 * also apply for driver shutdown and unload). The register API is
33 * also mandatory during RX-ring setup.
37 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
38 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
43 u32 type; /* enum xdp_mem_type, but known size type */
47 struct net_device *dev;
50 struct xdp_mem_info mem;
51 } ____cacheline_aligned; /* perf critical, avoid false-sharing */
57 void *data_hard_start;
58 struct xdp_rxq_info *rxq;
62 void xdp_return_frame(void *data, struct xdp_mem_info *mem)
64 if (mem->type == MEM_TYPE_PAGE_SHARED)
67 if (mem->type == MEM_TYPE_PAGE_ORDER0) {
68 struct page *page = virt_to_page(data); /* Assumes order0 page*/
74 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
75 struct net_device *dev, u32 queue_index);
76 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
77 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
78 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
79 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
80 enum xdp_mem_type type, void *allocator);
82 /* Drivers not supporting XDP metadata can use this helper, which
83 * rejects any room expansion for metadata as a result.
85 static __always_inline void
86 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
88 xdp->data_meta = xdp->data + 1;
91 static __always_inline bool
92 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
94 return unlikely(xdp->data_meta > xdp->data);
97 #endif /* __LINUX_NET_XDP_H__ */