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250 lines
5.9 KiB
250 lines
5.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* XSKMAP used for AF_XDP sockets |
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* Copyright(c) 2018 Intel Corporation. |
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*/ |
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#include <linux/bpf.h> |
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#include <linux/capability.h> |
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#include <net/xdp_sock.h> |
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#include <linux/slab.h> |
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#include <linux/sched.h> |
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#include "xsk.h" |
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static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map, |
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struct xdp_sock **map_entry) |
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{ |
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struct xsk_map_node *node; |
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node = bpf_map_kzalloc(&map->map, sizeof(*node), |
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GFP_ATOMIC | __GFP_NOWARN); |
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if (!node) |
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return ERR_PTR(-ENOMEM); |
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bpf_map_inc(&map->map); |
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node->map = map; |
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node->map_entry = map_entry; |
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return node; |
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} |
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static void xsk_map_node_free(struct xsk_map_node *node) |
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{ |
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bpf_map_put(&node->map->map); |
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kfree(node); |
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} |
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static void xsk_map_sock_add(struct xdp_sock *xs, struct xsk_map_node *node) |
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{ |
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spin_lock_bh(&xs->map_list_lock); |
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list_add_tail(&node->node, &xs->map_list); |
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spin_unlock_bh(&xs->map_list_lock); |
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} |
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static void xsk_map_sock_delete(struct xdp_sock *xs, |
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struct xdp_sock **map_entry) |
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{ |
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struct xsk_map_node *n, *tmp; |
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spin_lock_bh(&xs->map_list_lock); |
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list_for_each_entry_safe(n, tmp, &xs->map_list, node) { |
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if (map_entry == n->map_entry) { |
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list_del(&n->node); |
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xsk_map_node_free(n); |
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} |
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} |
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spin_unlock_bh(&xs->map_list_lock); |
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} |
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static struct bpf_map *xsk_map_alloc(union bpf_attr *attr) |
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{ |
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struct xsk_map *m; |
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int numa_node; |
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u64 size; |
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if (!capable(CAP_NET_ADMIN)) |
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return ERR_PTR(-EPERM); |
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if (attr->max_entries == 0 || attr->key_size != 4 || |
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attr->value_size != 4 || |
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attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)) |
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return ERR_PTR(-EINVAL); |
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numa_node = bpf_map_attr_numa_node(attr); |
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size = struct_size(m, xsk_map, attr->max_entries); |
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m = bpf_map_area_alloc(size, numa_node); |
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if (!m) |
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return ERR_PTR(-ENOMEM); |
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bpf_map_init_from_attr(&m->map, attr); |
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spin_lock_init(&m->lock); |
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return &m->map; |
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} |
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static void xsk_map_free(struct bpf_map *map) |
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{ |
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struct xsk_map *m = container_of(map, struct xsk_map, map); |
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bpf_clear_redirect_map(map); |
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synchronize_net(); |
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bpf_map_area_free(m); |
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} |
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static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key) |
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{ |
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struct xsk_map *m = container_of(map, struct xsk_map, map); |
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u32 index = key ? *(u32 *)key : U32_MAX; |
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u32 *next = next_key; |
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if (index >= m->map.max_entries) { |
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*next = 0; |
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return 0; |
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} |
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if (index == m->map.max_entries - 1) |
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return -ENOENT; |
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*next = index + 1; |
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return 0; |
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} |
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static int xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) |
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{ |
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const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2; |
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struct bpf_insn *insn = insn_buf; |
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*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); |
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*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); |
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*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *))); |
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*insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map)); |
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*insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp); |
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*insn++ = BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ret, ret, 0); |
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*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); |
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*insn++ = BPF_MOV64_IMM(ret, 0); |
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return insn - insn_buf; |
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} |
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static void *xsk_map_lookup_elem(struct bpf_map *map, void *key) |
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{ |
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WARN_ON_ONCE(!rcu_read_lock_held()); |
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return __xsk_map_lookup_elem(map, *(u32 *)key); |
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} |
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static void *xsk_map_lookup_elem_sys_only(struct bpf_map *map, void *key) |
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{ |
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return ERR_PTR(-EOPNOTSUPP); |
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} |
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static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value, |
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u64 map_flags) |
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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, *old_xs, **map_entry; |
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u32 i = *(u32 *)key, fd = *(u32 *)value; |
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struct xsk_map_node *node; |
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struct socket *sock; |
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int err; |
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if (unlikely(map_flags > BPF_EXIST)) |
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return -EINVAL; |
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if (unlikely(i >= m->map.max_entries)) |
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return -E2BIG; |
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sock = sockfd_lookup(fd, &err); |
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if (!sock) |
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return err; |
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if (sock->sk->sk_family != PF_XDP) { |
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sockfd_put(sock); |
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return -EOPNOTSUPP; |
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} |
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xs = (struct xdp_sock *)sock->sk; |
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map_entry = &m->xsk_map[i]; |
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node = xsk_map_node_alloc(m, map_entry); |
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if (IS_ERR(node)) { |
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sockfd_put(sock); |
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return PTR_ERR(node); |
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} |
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spin_lock_bh(&m->lock); |
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old_xs = READ_ONCE(*map_entry); |
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if (old_xs == xs) { |
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err = 0; |
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goto out; |
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} else if (old_xs && map_flags == BPF_NOEXIST) { |
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err = -EEXIST; |
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goto out; |
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} else if (!old_xs && map_flags == BPF_EXIST) { |
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err = -ENOENT; |
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goto out; |
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} |
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xsk_map_sock_add(xs, node); |
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WRITE_ONCE(*map_entry, xs); |
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if (old_xs) |
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xsk_map_sock_delete(old_xs, map_entry); |
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spin_unlock_bh(&m->lock); |
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sockfd_put(sock); |
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return 0; |
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out: |
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spin_unlock_bh(&m->lock); |
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sockfd_put(sock); |
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xsk_map_node_free(node); |
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return err; |
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} |
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static int xsk_map_delete_elem(struct bpf_map *map, void *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 *old_xs, **map_entry; |
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int k = *(u32 *)key; |
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if (k >= map->max_entries) |
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return -EINVAL; |
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spin_lock_bh(&m->lock); |
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map_entry = &m->xsk_map[k]; |
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old_xs = xchg(map_entry, NULL); |
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if (old_xs) |
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xsk_map_sock_delete(old_xs, map_entry); |
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spin_unlock_bh(&m->lock); |
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return 0; |
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} |
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void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, |
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struct xdp_sock **map_entry) |
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{ |
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spin_lock_bh(&map->lock); |
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if (READ_ONCE(*map_entry) == xs) { |
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WRITE_ONCE(*map_entry, NULL); |
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xsk_map_sock_delete(xs, map_entry); |
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} |
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spin_unlock_bh(&map->lock); |
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} |
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static bool xsk_map_meta_equal(const struct bpf_map *meta0, |
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const struct bpf_map *meta1) |
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{ |
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return meta0->max_entries == meta1->max_entries && |
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bpf_map_meta_equal(meta0, meta1); |
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} |
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static int xsk_map_btf_id; |
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const struct bpf_map_ops xsk_map_ops = { |
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.map_meta_equal = xsk_map_meta_equal, |
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.map_alloc = xsk_map_alloc, |
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.map_free = xsk_map_free, |
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.map_get_next_key = xsk_map_get_next_key, |
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.map_lookup_elem = xsk_map_lookup_elem, |
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.map_gen_lookup = xsk_map_gen_lookup, |
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.map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only, |
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.map_update_elem = xsk_map_update_elem, |
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.map_delete_elem = xsk_map_delete_elem, |
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.map_check_btf = map_check_no_btf, |
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.map_btf_name = "xsk_map", |
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.map_btf_id = &xsk_map_btf_id, |
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};
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