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-rw-r--r--kernel/bpf/hashtab.c123
1 files changed, 114 insertions, 9 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index d7ebb12ffffc..72c58cc516a3 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -46,12 +46,12 @@
* events, kprobes and tracing to be invoked before the prior invocation
* from one of these contexts completed. sys_bpf() uses the same mechanism
* by pinning the task to the current CPU and incrementing the recursion
- * protection accross the map operation.
+ * protection across the map operation.
*
* This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
* operations like memory allocations (even with GFP_ATOMIC) from atomic
* contexts. This is required because even with GFP_ATOMIC the memory
- * allocator calls into code pathes which acquire locks with long held lock
+ * allocator calls into code paths which acquire locks with long held lock
* sections. To ensure the deterministic behaviour these locks are regular
* spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
* true atomic contexts on an RT kernel are the low level hardware
@@ -596,7 +596,8 @@ static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
struct htab_elem *l;
u32 hash, key_size;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -989,7 +990,8 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1082,7 +1084,8 @@ static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1148,7 +1151,8 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1202,7 +1206,8 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
/* unknown flags */
return -EINVAL;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1276,7 +1281,8 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
u32 hash, key_size;
int ret;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1311,7 +1317,8 @@ static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
u32 hash, key_size;
int ret;
- WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held());
+ WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
+ !rcu_read_lock_bh_held());
key_size = map->key_size;
@@ -1401,6 +1408,100 @@ static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
rcu_read_unlock();
}
+static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, bool is_lru_map,
+ bool is_percpu, u64 flags)
+{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+ struct hlist_nulls_head *head;
+ unsigned long bflags;
+ struct htab_elem *l;
+ u32 hash, key_size;
+ struct bucket *b;
+ int ret;
+
+ key_size = map->key_size;
+
+ hash = htab_map_hash(key, key_size, htab->hashrnd);
+ b = __select_bucket(htab, hash);
+ head = &b->head;
+
+ ret = htab_lock_bucket(htab, b, hash, &bflags);
+ if (ret)
+ return ret;
+
+ l = lookup_elem_raw(head, hash, key, key_size);
+ if (!l) {
+ ret = -ENOENT;
+ } else {
+ if (is_percpu) {
+ u32 roundup_value_size = round_up(map->value_size, 8);
+ void __percpu *pptr;
+ int off = 0, cpu;
+
+ pptr = htab_elem_get_ptr(l, key_size);
+ for_each_possible_cpu(cpu) {
+ bpf_long_memcpy(value + off,
+ per_cpu_ptr(pptr, cpu),
+ roundup_value_size);
+ off += roundup_value_size;
+ }
+ } else {
+ u32 roundup_key_size = round_up(map->key_size, 8);
+
+ if (flags & BPF_F_LOCK)
+ copy_map_value_locked(map, value, l->key +
+ roundup_key_size,
+ true);
+ else
+ copy_map_value(map, value, l->key +
+ roundup_key_size);
+ check_and_init_map_lock(map, value);
+ }
+
+ hlist_nulls_del_rcu(&l->hash_node);
+ if (!is_lru_map)
+ free_htab_elem(htab, l);
+ }
+
+ htab_unlock_bucket(htab, b, hash, bflags);
+
+ if (is_lru_map && l)
+ bpf_lru_push_free(&htab->lru, &l->lru_node);
+
+ return ret;
+}
+
+static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, false, false,
+ flags);
+}
+
+static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+ void *key, void *value,
+ u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, false, true,
+ flags);
+}
+
+static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, true, false,
+ flags);
+}
+
+static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map,
+ void *key, void *value,
+ u64 flags)
+{
+ return __htab_map_lookup_and_delete_elem(map, key, value, true, true,
+ flags);
+}
+
static int
__htab_map_lookup_and_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
@@ -1934,6 +2035,7 @@ const struct bpf_map_ops htab_map_ops = {
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_lookup_elem = htab_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem,
.map_update_elem = htab_map_update_elem,
.map_delete_elem = htab_map_delete_elem,
.map_gen_lookup = htab_map_gen_lookup,
@@ -1954,6 +2056,7 @@ const struct bpf_map_ops htab_lru_map_ops = {
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_lookup_elem = htab_lru_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem,
.map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys,
.map_update_elem = htab_lru_map_update_elem,
.map_delete_elem = htab_lru_map_delete_elem,
@@ -2077,6 +2180,7 @@ const struct bpf_map_ops htab_percpu_map_ops = {
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_lookup_elem = htab_percpu_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem,
.map_update_elem = htab_percpu_map_update_elem,
.map_delete_elem = htab_map_delete_elem,
.map_seq_show_elem = htab_percpu_map_seq_show_elem,
@@ -2096,6 +2200,7 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = {
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_lookup_elem = htab_lru_percpu_map_lookup_elem,
+ .map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem,
.map_update_elem = htab_lru_percpu_map_update_elem,
.map_delete_elem = htab_lru_map_delete_elem,
.map_seq_show_elem = htab_percpu_map_seq_show_elem,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.