#include "xsk.h"
static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map,
- struct xdp_sock **map_entry)
+ struct xdp_sock __rcu **map_entry)
{
struct xsk_map_node *node;
}
static void xsk_map_sock_delete(struct xdp_sock *xs,
- struct xdp_sock **map_entry)
+ struct xdp_sock __rcu **map_entry)
{
struct xsk_map_node *n, *tmp;
return insn - insn_buf;
}
+/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or
+ * by local_bh_disable() (from XDP calls inside NAPI). The
+ * rcu_read_lock_bh_held() below makes lockdep accept both.
+ */
static void *__xsk_map_lookup_elem(struct bpf_map *map, u32 key)
{
struct xsk_map *m = container_of(map, struct xsk_map, map);
if (key >= map->max_entries)
return NULL;
- return READ_ONCE(m->xsk_map[key]);
+ return rcu_dereference_check(m->xsk_map[key], rcu_read_lock_bh_held());
}
static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
{
- WARN_ON_ONCE(!rcu_read_lock_held());
return __xsk_map_lookup_elem(map, *(u32 *)key);
}
u64 map_flags)
{
struct xsk_map *m = container_of(map, struct xsk_map, map);
- struct xdp_sock *xs, *old_xs, **map_entry;
+ struct xdp_sock __rcu **map_entry;
+ struct xdp_sock *xs, *old_xs;
u32 i = *(u32 *)key, fd = *(u32 *)value;
struct xsk_map_node *node;
struct socket *sock;
}
spin_lock_bh(&m->lock);
- old_xs = READ_ONCE(*map_entry);
+ old_xs = rcu_dereference_protected(*map_entry, lockdep_is_held(&m->lock));
if (old_xs == xs) {
err = 0;
goto out;
goto out;
}
xsk_map_sock_add(xs, node);
- WRITE_ONCE(*map_entry, xs);
+ rcu_assign_pointer(*map_entry, xs);
if (old_xs)
xsk_map_sock_delete(old_xs, map_entry);
spin_unlock_bh(&m->lock);
static int xsk_map_delete_elem(struct bpf_map *map, void *key)
{
struct xsk_map *m = container_of(map, struct xsk_map, map);
- struct xdp_sock *old_xs, **map_entry;
+ struct xdp_sock __rcu **map_entry;
+ struct xdp_sock *old_xs;
int k = *(u32 *)key;
if (k >= map->max_entries)
spin_lock_bh(&m->lock);
map_entry = &m->xsk_map[k];
- old_xs = xchg(map_entry, NULL);
+ old_xs = unrcu_pointer(xchg(map_entry, NULL));
if (old_xs)
xsk_map_sock_delete(old_xs, map_entry);
spin_unlock_bh(&m->lock);
}
void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
- struct xdp_sock **map_entry)
+ struct xdp_sock __rcu **map_entry)
{
spin_lock_bh(&map->lock);
- if (READ_ONCE(*map_entry) == xs) {
- WRITE_ONCE(*map_entry, NULL);
+ if (rcu_access_pointer(*map_entry) == xs) {
+ rcu_assign_pointer(*map_entry, NULL);
xsk_map_sock_delete(xs, map_entry);
}
spin_unlock_bh(&map->lock);