
In order to simplify AF_XDP zero-copy enablement for NIC driver developers, a new AF_XDP buffer allocation API is added. The implementation is based on a single core (single producer/consumer) buffer pool for the AF_XDP UMEM. A buffer is allocated using the xsk_buff_alloc() function, and returned using xsk_buff_free(). If a buffer is disassociated with the pool, e.g. when a buffer is passed to an AF_XDP socket, a buffer is said to be released. Currently, the release function is only used by the AF_XDP internals and not visible to the driver. Drivers using this API should register the XDP memory model with the new MEM_TYPE_XSK_BUFF_POOL type. The API is defined in net/xdp_sock_drv.h. The buffer type is struct xdp_buff, and follows the lifetime of regular xdp_buffs, i.e. the lifetime of an xdp_buff is restricted to a NAPI context. In other words, the API is not replacing xdp_frames. In addition to introducing the API and implementations, the AF_XDP core is migrated to use the new APIs. rfc->v1: Fixed build errors/warnings for m68k and riscv. (kbuild test robot) Added headroom/chunk size getter. (Maxim/Björn) v1->v2: Swapped SoBs. (Maxim) v2->v3: Initialize struct xdp_buff member frame_sz. (Björn) Add API to query the DMA address of a frame. (Maxim) Do DMA sync for CPU till the end of the frame to handle possible growth (frame_sz). (Maxim) Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com
167 lines
3.2 KiB
C
167 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* AF_XDP internal functions
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* Copyright(c) 2018 Intel Corporation.
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*/
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#ifndef _LINUX_XDP_SOCK_H
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#define _LINUX_XDP_SOCK_H
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#include <linux/workqueue.h>
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#include <linux/if_xdp.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/mm.h>
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#include <net/sock.h>
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struct net_device;
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struct xsk_queue;
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struct xdp_buff;
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struct xdp_umem_page {
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void *addr;
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dma_addr_t dma;
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};
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struct xdp_umem_fq_reuse {
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u32 nentries;
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u32 length;
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u64 handles[];
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};
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struct xdp_umem {
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struct xsk_queue *fq;
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struct xsk_queue *cq;
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struct xsk_buff_pool *pool;
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struct xdp_umem_page *pages;
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u64 chunk_mask;
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u64 size;
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u32 headroom;
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u32 chunk_size_nohr;
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u32 chunk_size;
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struct user_struct *user;
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refcount_t users;
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struct work_struct work;
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struct page **pgs;
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u32 npgs;
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u16 queue_id;
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u8 need_wakeup;
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u8 flags;
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int id;
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struct net_device *dev;
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struct xdp_umem_fq_reuse *fq_reuse;
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bool zc;
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spinlock_t xsk_tx_list_lock;
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struct list_head xsk_tx_list;
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};
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struct xsk_map {
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struct bpf_map map;
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spinlock_t lock; /* Synchronize map updates */
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struct xdp_sock *xsk_map[];
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};
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struct xdp_sock {
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/* struct sock must be the first member of struct xdp_sock */
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struct sock sk;
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struct xsk_queue *rx;
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struct net_device *dev;
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struct xdp_umem *umem;
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struct list_head flush_node;
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u16 queue_id;
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bool zc;
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enum {
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XSK_READY = 0,
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XSK_BOUND,
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XSK_UNBOUND,
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} state;
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/* Protects multiple processes in the control path */
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struct mutex mutex;
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struct xsk_queue *tx ____cacheline_aligned_in_smp;
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struct list_head list;
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/* Mutual exclusion of NAPI TX thread and sendmsg error paths
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* in the SKB destructor callback.
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*/
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spinlock_t tx_completion_lock;
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/* Protects generic receive. */
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spinlock_t rx_lock;
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u64 rx_dropped;
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struct list_head map_list;
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/* Protects map_list */
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spinlock_t map_list_lock;
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};
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#ifdef CONFIG_XDP_SOCKETS
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int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
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int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp);
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void __xsk_map_flush(void);
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static inline struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map,
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u32 key)
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{
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struct xsk_map *m = container_of(map, struct xsk_map, map);
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struct xdp_sock *xs;
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if (key >= map->max_entries)
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return NULL;
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xs = READ_ONCE(m->xsk_map[key]);
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return xs;
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}
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static inline u64 xsk_umem_extract_addr(u64 addr)
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{
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return addr & XSK_UNALIGNED_BUF_ADDR_MASK;
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}
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static inline u64 xsk_umem_extract_offset(u64 addr)
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{
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return addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
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}
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static inline u64 xsk_umem_add_offset_to_addr(u64 addr)
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{
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return xsk_umem_extract_addr(addr) + xsk_umem_extract_offset(addr);
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}
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#else
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static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
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{
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return -ENOTSUPP;
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}
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static inline int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
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{
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return -EOPNOTSUPP;
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}
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static inline void __xsk_map_flush(void)
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{
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}
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static inline struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map,
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u32 key)
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{
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return NULL;
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}
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static inline u64 xsk_umem_extract_addr(u64 addr)
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{
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return 0;
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}
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static inline u64 xsk_umem_extract_offset(u64 addr)
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{
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return 0;
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}
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static inline u64 xsk_umem_add_offset_to_addr(u64 addr)
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{
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return 0;
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}
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#endif /* CONFIG_XDP_SOCKETS */
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#endif /* _LINUX_XDP_SOCK_H */
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