linux/kernel/bpf/hashtab.c
Andrii Nakryiko 6c3eba1c5e bpf: Centralize permissions checks for all BPF map types
This allows to do more centralized decisions later on, and generally
makes it very explicit which maps are privileged and which are not
(e.g., LRU_HASH and LRU_PERCPU_HASH, which are privileged HASH variants,
as opposed to unprivileged HASH and HASH_PERCPU; now this is explicit
and easy to verify).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-4-andrii@kernel.org
2023-06-19 14:04:04 +02:00

2581 lines
68 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
* Copyright (c) 2016 Facebook
*/
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/jhash.h>
#include <linux/filter.h>
#include <linux/rculist_nulls.h>
#include <linux/random.h>
#include <uapi/linux/btf.h>
#include <linux/rcupdate_trace.h>
#include <linux/btf_ids.h>
#include "percpu_freelist.h"
#include "bpf_lru_list.h"
#include "map_in_map.h"
#include <linux/bpf_mem_alloc.h>
#define HTAB_CREATE_FLAG_MASK \
(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
#define BATCH_OPS(_name) \
.map_lookup_batch = \
_name##_map_lookup_batch, \
.map_lookup_and_delete_batch = \
_name##_map_lookup_and_delete_batch, \
.map_update_batch = \
generic_map_update_batch, \
.map_delete_batch = \
generic_map_delete_batch
/*
* The bucket lock has two protection scopes:
*
* 1) Serializing concurrent operations from BPF programs on different
* CPUs
*
* 2) Serializing concurrent operations from BPF programs and sys_bpf()
*
* BPF programs can execute in any context including perf, kprobes and
* tracing. As there are almost no limits where perf, kprobes and tracing
* can be invoked from the lock operations need to be protected against
* deadlocks. Deadlocks can be caused by recursion and by an invocation in
* the lock held section when functions which acquire this lock are invoked
* from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
* variable bpf_prog_active, which prevents BPF programs attached to perf
* 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 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 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
* handling, scheduling, low level interrupt handling, NMIs etc. None of
* these contexts should ever do memory allocations.
*
* As regular device interrupt handlers and soft interrupts are forced into
* thread context, the existing code which does
* spin_lock*(); alloc(GFP_ATOMIC); spin_unlock*();
* just works.
*
* In theory the BPF locks could be converted to regular spinlocks as well,
* but the bucket locks and percpu_freelist locks can be taken from
* arbitrary contexts (perf, kprobes, tracepoints) which are required to be
* atomic contexts even on RT. Before the introduction of bpf_mem_alloc,
* it is only safe to use raw spinlock for preallocated hash map on a RT kernel,
* because there is no memory allocation within the lock held sections. However
* after hash map was fully converted to use bpf_mem_alloc, there will be
* non-synchronous memory allocation for non-preallocated hash map, so it is
* safe to always use raw spinlock for bucket lock.
*/
struct bucket {
struct hlist_nulls_head head;
raw_spinlock_t raw_lock;
};
#define HASHTAB_MAP_LOCK_COUNT 8
#define HASHTAB_MAP_LOCK_MASK (HASHTAB_MAP_LOCK_COUNT - 1)
struct bpf_htab {
struct bpf_map map;
struct bpf_mem_alloc ma;
struct bpf_mem_alloc pcpu_ma;
struct bucket *buckets;
void *elems;
union {
struct pcpu_freelist freelist;
struct bpf_lru lru;
};
struct htab_elem *__percpu *extra_elems;
/* number of elements in non-preallocated hashtable are kept
* in either pcount or count
*/
struct percpu_counter pcount;
atomic_t count;
bool use_percpu_counter;
u32 n_buckets; /* number of hash buckets */
u32 elem_size; /* size of each element in bytes */
u32 hashrnd;
struct lock_class_key lockdep_key;
int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT];
};
/* each htab element is struct htab_elem + key + value */
struct htab_elem {
union {
struct hlist_nulls_node hash_node;
struct {
void *padding;
union {
struct pcpu_freelist_node fnode;
struct htab_elem *batch_flink;
};
};
};
union {
/* pointer to per-cpu pointer */
void *ptr_to_pptr;
struct bpf_lru_node lru_node;
};
u32 hash;
char key[] __aligned(8);
};
static inline bool htab_is_prealloc(const struct bpf_htab *htab)
{
return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
}
static void htab_init_buckets(struct bpf_htab *htab)
{
unsigned int i;
for (i = 0; i < htab->n_buckets; i++) {
INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
raw_spin_lock_init(&htab->buckets[i].raw_lock);
lockdep_set_class(&htab->buckets[i].raw_lock,
&htab->lockdep_key);
cond_resched();
}
}
static inline int htab_lock_bucket(const struct bpf_htab *htab,
struct bucket *b, u32 hash,
unsigned long *pflags)
{
unsigned long flags;
hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
preempt_disable();
if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) {
__this_cpu_dec(*(htab->map_locked[hash]));
preempt_enable();
return -EBUSY;
}
raw_spin_lock_irqsave(&b->raw_lock, flags);
*pflags = flags;
return 0;
}
static inline void htab_unlock_bucket(const struct bpf_htab *htab,
struct bucket *b, u32 hash,
unsigned long flags)
{
hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1);
raw_spin_unlock_irqrestore(&b->raw_lock, flags);
__this_cpu_dec(*(htab->map_locked[hash]));
preempt_enable();
}
static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
static bool htab_is_lru(const struct bpf_htab *htab)
{
return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
}
static bool htab_is_percpu(const struct bpf_htab *htab)
{
return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
}
static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
void __percpu *pptr)
{
*(void __percpu **)(l->key + key_size) = pptr;
}
static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
{
return *(void __percpu **)(l->key + key_size);
}
static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
{
return *(void **)(l->key + roundup(map->key_size, 8));
}
static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
{
return (struct htab_elem *) (htab->elems + i * (u64)htab->elem_size);
}
static bool htab_has_extra_elems(struct bpf_htab *htab)
{
return !htab_is_percpu(htab) && !htab_is_lru(htab);
}
static void htab_free_prealloced_timers(struct bpf_htab *htab)
{
u32 num_entries = htab->map.max_entries;
int i;
if (!btf_record_has_field(htab->map.record, BPF_TIMER))
return;
if (htab_has_extra_elems(htab))
num_entries += num_possible_cpus();
for (i = 0; i < num_entries; i++) {
struct htab_elem *elem;
elem = get_htab_elem(htab, i);
bpf_obj_free_timer(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
cond_resched();
}
}
static void htab_free_prealloced_fields(struct bpf_htab *htab)
{
u32 num_entries = htab->map.max_entries;
int i;
if (IS_ERR_OR_NULL(htab->map.record))
return;
if (htab_has_extra_elems(htab))
num_entries += num_possible_cpus();
for (i = 0; i < num_entries; i++) {
struct htab_elem *elem;
elem = get_htab_elem(htab, i);
if (htab_is_percpu(htab)) {
void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
int cpu;
for_each_possible_cpu(cpu) {
bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
cond_resched();
}
} else {
bpf_obj_free_fields(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
cond_resched();
}
cond_resched();
}
}
static void htab_free_elems(struct bpf_htab *htab)
{
int i;
if (!htab_is_percpu(htab))
goto free_elems;
for (i = 0; i < htab->map.max_entries; i++) {
void __percpu *pptr;
pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
htab->map.key_size);
free_percpu(pptr);
cond_resched();
}
free_elems:
bpf_map_area_free(htab->elems);
}
/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
* (bucket_lock). If both locks need to be acquired together, the lock
* order is always lru_lock -> bucket_lock and this only happens in
* bpf_lru_list.c logic. For example, certain code path of
* bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
* will acquire lru_lock first followed by acquiring bucket_lock.
*
* In hashtab.c, to avoid deadlock, lock acquisition of
* bucket_lock followed by lru_lock is not allowed. In such cases,
* bucket_lock needs to be released first before acquiring lru_lock.
*/
static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
u32 hash)
{
struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
struct htab_elem *l;
if (node) {
l = container_of(node, struct htab_elem, lru_node);
memcpy(l->key, key, htab->map.key_size);
return l;
}
return NULL;
}
static int prealloc_init(struct bpf_htab *htab)
{
u32 num_entries = htab->map.max_entries;
int err = -ENOMEM, i;
if (htab_has_extra_elems(htab))
num_entries += num_possible_cpus();
htab->elems = bpf_map_area_alloc((u64)htab->elem_size * num_entries,
htab->map.numa_node);
if (!htab->elems)
return -ENOMEM;
if (!htab_is_percpu(htab))
goto skip_percpu_elems;
for (i = 0; i < num_entries; i++) {
u32 size = round_up(htab->map.value_size, 8);
void __percpu *pptr;
pptr = bpf_map_alloc_percpu(&htab->map, size, 8,
GFP_USER | __GFP_NOWARN);
if (!pptr)
goto free_elems;
htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
pptr);
cond_resched();
}
skip_percpu_elems:
if (htab_is_lru(htab))
err = bpf_lru_init(&htab->lru,
htab->map.map_flags & BPF_F_NO_COMMON_LRU,
offsetof(struct htab_elem, hash) -
offsetof(struct htab_elem, lru_node),
htab_lru_map_delete_node,
htab);
else
err = pcpu_freelist_init(&htab->freelist);
if (err)
goto free_elems;
if (htab_is_lru(htab))
bpf_lru_populate(&htab->lru, htab->elems,
offsetof(struct htab_elem, lru_node),
htab->elem_size, num_entries);
else
pcpu_freelist_populate(&htab->freelist,
htab->elems + offsetof(struct htab_elem, fnode),
htab->elem_size, num_entries);
return 0;
free_elems:
htab_free_elems(htab);
return err;
}
static void prealloc_destroy(struct bpf_htab *htab)
{
htab_free_elems(htab);
if (htab_is_lru(htab))
bpf_lru_destroy(&htab->lru);
else
pcpu_freelist_destroy(&htab->freelist);
}
static int alloc_extra_elems(struct bpf_htab *htab)
{
struct htab_elem *__percpu *pptr, *l_new;
struct pcpu_freelist_node *l;
int cpu;
pptr = bpf_map_alloc_percpu(&htab->map, sizeof(struct htab_elem *), 8,
GFP_USER | __GFP_NOWARN);
if (!pptr)
return -ENOMEM;
for_each_possible_cpu(cpu) {
l = pcpu_freelist_pop(&htab->freelist);
/* pop will succeed, since prealloc_init()
* preallocated extra num_possible_cpus elements
*/
l_new = container_of(l, struct htab_elem, fnode);
*per_cpu_ptr(pptr, cpu) = l_new;
}
htab->extra_elems = pptr;
return 0;
}
/* Called from syscall */
static int htab_map_alloc_check(union bpf_attr *attr)
{
bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
/* percpu_lru means each cpu has its own LRU list.
* it is different from BPF_MAP_TYPE_PERCPU_HASH where
* the map's value itself is percpu. percpu_lru has
* nothing to do with the map's value.
*/
bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
int numa_node = bpf_map_attr_numa_node(attr);
BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
offsetof(struct htab_elem, hash_node.pprev));
if (zero_seed && !capable(CAP_SYS_ADMIN))
/* Guard against local DoS, and discourage production use. */
return -EPERM;
if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
!bpf_map_flags_access_ok(attr->map_flags))
return -EINVAL;
if (!lru && percpu_lru)
return -EINVAL;
if (lru && !prealloc)
return -ENOTSUPP;
if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
return -EINVAL;
/* check sanity of attributes.
* value_size == 0 may be allowed in the future to use map as a set
*/
if (attr->max_entries == 0 || attr->key_size == 0 ||
attr->value_size == 0)
return -EINVAL;
if ((u64)attr->key_size + attr->value_size >= KMALLOC_MAX_SIZE -
sizeof(struct htab_elem))
/* if key_size + value_size is bigger, the user space won't be
* able to access the elements via bpf syscall. This check
* also makes sure that the elem_size doesn't overflow and it's
* kmalloc-able later in htab_map_update_elem()
*/
return -E2BIG;
return 0;
}
static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
{
bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
/* percpu_lru means each cpu has its own LRU list.
* it is different from BPF_MAP_TYPE_PERCPU_HASH where
* the map's value itself is percpu. percpu_lru has
* nothing to do with the map's value.
*/
bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
struct bpf_htab *htab;
int err, i;
htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE);
if (!htab)
return ERR_PTR(-ENOMEM);
lockdep_register_key(&htab->lockdep_key);
bpf_map_init_from_attr(&htab->map, attr);
if (percpu_lru) {
/* ensure each CPU's lru list has >=1 elements.
* since we are at it, make each lru list has the same
* number of elements.
*/
htab->map.max_entries = roundup(attr->max_entries,
num_possible_cpus());
if (htab->map.max_entries < attr->max_entries)
htab->map.max_entries = rounddown(attr->max_entries,
num_possible_cpus());
}
/* hash table size must be power of 2 */
htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
err = -E2BIG;
/* prevent zero size kmalloc and check for u32 overflow */
if (htab->n_buckets == 0 ||
htab->n_buckets > U32_MAX / sizeof(struct bucket))
goto free_htab;
err = -ENOMEM;
htab->buckets = bpf_map_area_alloc(htab->n_buckets *
sizeof(struct bucket),
htab->map.numa_node);
if (!htab->buckets)
goto free_htab;
for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) {
htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map,
sizeof(int),
sizeof(int),
GFP_USER);
if (!htab->map_locked[i])
goto free_map_locked;
}
if (htab->map.map_flags & BPF_F_ZERO_SEED)
htab->hashrnd = 0;
else
htab->hashrnd = get_random_u32();
htab_init_buckets(htab);
/* compute_batch_value() computes batch value as num_online_cpus() * 2
* and __percpu_counter_compare() needs
* htab->max_entries - cur_number_of_elems to be more than batch * num_online_cpus()
* for percpu_counter to be faster than atomic_t. In practice the average bpf
* hash map size is 10k, which means that a system with 64 cpus will fill
* hashmap to 20% of 10k before percpu_counter becomes ineffective. Therefore
* define our own batch count as 32 then 10k hash map can be filled up to 80%:
* 10k - 8k > 32 _batch_ * 64 _cpus_
* and __percpu_counter_compare() will still be fast. At that point hash map
* collisions will dominate its performance anyway. Assume that hash map filled
* to 50+% isn't going to be O(1) and use the following formula to choose
* between percpu_counter and atomic_t.
*/
#define PERCPU_COUNTER_BATCH 32
if (attr->max_entries / 2 > num_online_cpus() * PERCPU_COUNTER_BATCH)
htab->use_percpu_counter = true;
if (htab->use_percpu_counter) {
err = percpu_counter_init(&htab->pcount, 0, GFP_KERNEL);
if (err)
goto free_map_locked;
}
if (prealloc) {
err = prealloc_init(htab);
if (err)
goto free_map_locked;
if (!percpu && !lru) {
/* lru itself can remove the least used element, so
* there is no need for an extra elem during map_update.
*/
err = alloc_extra_elems(htab);
if (err)
goto free_prealloc;
}
} else {
err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false);
if (err)
goto free_map_locked;
if (percpu) {
err = bpf_mem_alloc_init(&htab->pcpu_ma,
round_up(htab->map.value_size, 8), true);
if (err)
goto free_map_locked;
}
}
return &htab->map;
free_prealloc:
prealloc_destroy(htab);
free_map_locked:
if (htab->use_percpu_counter)
percpu_counter_destroy(&htab->pcount);
for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
free_percpu(htab->map_locked[i]);
bpf_map_area_free(htab->buckets);
bpf_mem_alloc_destroy(&htab->pcpu_ma);
bpf_mem_alloc_destroy(&htab->ma);
free_htab:
lockdep_unregister_key(&htab->lockdep_key);
bpf_map_area_free(htab);
return ERR_PTR(err);
}
static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd)
{
if (likely(key_len % 4 == 0))
return jhash2(key, key_len / 4, hashrnd);
return jhash(key, key_len, hashrnd);
}
static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
{
return &htab->buckets[hash & (htab->n_buckets - 1)];
}
static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash)
{
return &__select_bucket(htab, hash)->head;
}
/* this lookup function can only be called with bucket lock taken */
static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash,
void *key, u32 key_size)
{
struct hlist_nulls_node *n;
struct htab_elem *l;
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
if (l->hash == hash && !memcmp(&l->key, key, key_size))
return l;
return NULL;
}
/* can be called without bucket lock. it will repeat the loop in
* the unlikely event when elements moved from one bucket into another
* while link list is being walked
*/
static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head,
u32 hash, void *key,
u32 key_size, u32 n_buckets)
{
struct hlist_nulls_node *n;
struct htab_elem *l;
again:
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
if (l->hash == hash && !memcmp(&l->key, key, key_size))
return l;
if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1))))
goto again;
return NULL;
}
/* Called from syscall or from eBPF program directly, so
* arguments have to match bpf_map_lookup_elem() exactly.
* The return value is adjusted by BPF instructions
* in htab_map_gen_lookup().
*/
static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_head *head;
struct htab_elem *l;
u32 hash, key_size;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
key_size = map->key_size;
hash = htab_map_hash(key, key_size, htab->hashrnd);
head = select_bucket(htab, hash);
l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
return l;
}
static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
{
struct htab_elem *l = __htab_map_lookup_elem(map, key);
if (l)
return l->key + round_up(map->key_size, 8);
return NULL;
}
/* inline bpf_map_lookup_elem() call.
* Instead of:
* bpf_prog
* bpf_map_lookup_elem
* map->ops->map_lookup_elem
* htab_map_lookup_elem
* __htab_map_lookup_elem
* do:
* bpf_prog
* __htab_map_lookup_elem
*/
static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
(void *(*)(struct bpf_map *map, void *key))NULL));
*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
offsetof(struct htab_elem, key) +
round_up(map->key_size, 8));
return insn - insn_buf;
}
static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map,
void *key, const bool mark)
{
struct htab_elem *l = __htab_map_lookup_elem(map, key);
if (l) {
if (mark)
bpf_lru_node_set_ref(&l->lru_node);
return l->key + round_up(map->key_size, 8);
}
return NULL;
}
static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
{
return __htab_lru_map_lookup_elem(map, key, true);
}
static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key)
{
return __htab_lru_map_lookup_elem(map, key, false);
}
static int htab_lru_map_gen_lookup(struct bpf_map *map,
struct bpf_insn *insn_buf)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
const int ref_reg = BPF_REG_1;
BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
(void *(*)(struct bpf_map *map, void *key))NULL));
*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4);
*insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret,
offsetof(struct htab_elem, lru_node) +
offsetof(struct bpf_lru_node, ref));
*insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1);
*insn++ = BPF_ST_MEM(BPF_B, ret,
offsetof(struct htab_elem, lru_node) +
offsetof(struct bpf_lru_node, ref),
1);
*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
offsetof(struct htab_elem, key) +
round_up(map->key_size, 8));
return insn - insn_buf;
}
static void check_and_free_fields(struct bpf_htab *htab,
struct htab_elem *elem)
{
if (htab_is_percpu(htab)) {
void __percpu *pptr = htab_elem_get_ptr(elem, htab->map.key_size);
int cpu;
for_each_possible_cpu(cpu)
bpf_obj_free_fields(htab->map.record, per_cpu_ptr(pptr, cpu));
} else {
void *map_value = elem->key + round_up(htab->map.key_size, 8);
bpf_obj_free_fields(htab->map.record, map_value);
}
}
/* It is called from the bpf_lru_list when the LRU needs to delete
* older elements from the htab.
*/
static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
{
struct bpf_htab *htab = arg;
struct htab_elem *l = NULL, *tgt_l;
struct hlist_nulls_head *head;
struct hlist_nulls_node *n;
unsigned long flags;
struct bucket *b;
int ret;
tgt_l = container_of(node, struct htab_elem, lru_node);
b = __select_bucket(htab, tgt_l->hash);
head = &b->head;
ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags);
if (ret)
return false;
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
if (l == tgt_l) {
hlist_nulls_del_rcu(&l->hash_node);
check_and_free_fields(htab, l);
break;
}
htab_unlock_bucket(htab, b, tgt_l->hash, flags);
return l == tgt_l;
}
/* Called from syscall */
static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_head *head;
struct htab_elem *l, *next_l;
u32 hash, key_size;
int i = 0;
WARN_ON_ONCE(!rcu_read_lock_held());
key_size = map->key_size;
if (!key)
goto find_first_elem;
hash = htab_map_hash(key, key_size, htab->hashrnd);
head = select_bucket(htab, hash);
/* lookup the key */
l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
if (!l)
goto find_first_elem;
/* key was found, get next key in the same bucket */
next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
struct htab_elem, hash_node);
if (next_l) {
/* if next elem in this hash list is non-zero, just return it */
memcpy(next_key, next_l->key, key_size);
return 0;
}
/* no more elements in this hash list, go to the next bucket */
i = hash & (htab->n_buckets - 1);
i++;
find_first_elem:
/* iterate over buckets */
for (; i < htab->n_buckets; i++) {
head = select_bucket(htab, i);
/* pick first element in the bucket */
next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_first_rcu(head)),
struct htab_elem, hash_node);
if (next_l) {
/* if it's not empty, just return it */
memcpy(next_key, next_l->key, key_size);
return 0;
}
}
/* iterated over all buckets and all elements */
return -ENOENT;
}
static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l)
{
check_and_free_fields(htab, l);
if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)
bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr);
bpf_mem_cache_free(&htab->ma, l);
}
static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
{
struct bpf_map *map = &htab->map;
void *ptr;
if (map->ops->map_fd_put_ptr) {
ptr = fd_htab_map_get_ptr(map, l);
map->ops->map_fd_put_ptr(ptr);
}
}
static bool is_map_full(struct bpf_htab *htab)
{
if (htab->use_percpu_counter)
return __percpu_counter_compare(&htab->pcount, htab->map.max_entries,
PERCPU_COUNTER_BATCH) >= 0;
return atomic_read(&htab->count) >= htab->map.max_entries;
}
static void inc_elem_count(struct bpf_htab *htab)
{
if (htab->use_percpu_counter)
percpu_counter_add_batch(&htab->pcount, 1, PERCPU_COUNTER_BATCH);
else
atomic_inc(&htab->count);
}
static void dec_elem_count(struct bpf_htab *htab)
{
if (htab->use_percpu_counter)
percpu_counter_add_batch(&htab->pcount, -1, PERCPU_COUNTER_BATCH);
else
atomic_dec(&htab->count);
}
static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
{
htab_put_fd_value(htab, l);
if (htab_is_prealloc(htab)) {
check_and_free_fields(htab, l);
__pcpu_freelist_push(&htab->freelist, &l->fnode);
} else {
dec_elem_count(htab);
htab_elem_free(htab, l);
}
}
static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
void *value, bool onallcpus)
{
if (!onallcpus) {
/* copy true value_size bytes */
copy_map_value(&htab->map, this_cpu_ptr(pptr), value);
} else {
u32 size = round_up(htab->map.value_size, 8);
int off = 0, cpu;
for_each_possible_cpu(cpu) {
copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value + off);
off += size;
}
}
}
static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
void *value, bool onallcpus)
{
/* When not setting the initial value on all cpus, zero-fill element
* values for other cpus. Otherwise, bpf program has no way to ensure
* known initial values for cpus other than current one
* (onallcpus=false always when coming from bpf prog).
*/
if (!onallcpus) {
int current_cpu = raw_smp_processor_id();
int cpu;
for_each_possible_cpu(cpu) {
if (cpu == current_cpu)
copy_map_value_long(&htab->map, per_cpu_ptr(pptr, cpu), value);
else /* Since elem is preallocated, we cannot touch special fields */
zero_map_value(&htab->map, per_cpu_ptr(pptr, cpu));
}
} else {
pcpu_copy_value(htab, pptr, value, onallcpus);
}
}
static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
{
return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
BITS_PER_LONG == 64;
}
static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
void *value, u32 key_size, u32 hash,
bool percpu, bool onallcpus,
struct htab_elem *old_elem)
{
u32 size = htab->map.value_size;
bool prealloc = htab_is_prealloc(htab);
struct htab_elem *l_new, **pl_new;
void __percpu *pptr;
if (prealloc) {
if (old_elem) {
/* if we're updating the existing element,
* use per-cpu extra elems to avoid freelist_pop/push
*/
pl_new = this_cpu_ptr(htab->extra_elems);
l_new = *pl_new;
htab_put_fd_value(htab, old_elem);
*pl_new = old_elem;
} else {
struct pcpu_freelist_node *l;
l = __pcpu_freelist_pop(&htab->freelist);
if (!l)
return ERR_PTR(-E2BIG);
l_new = container_of(l, struct htab_elem, fnode);
}
} else {
if (is_map_full(htab))
if (!old_elem)
/* when map is full and update() is replacing
* old element, it's ok to allocate, since
* old element will be freed immediately.
* Otherwise return an error
*/
return ERR_PTR(-E2BIG);
inc_elem_count(htab);
l_new = bpf_mem_cache_alloc(&htab->ma);
if (!l_new) {
l_new = ERR_PTR(-ENOMEM);
goto dec_count;
}
}
memcpy(l_new->key, key, key_size);
if (percpu) {
if (prealloc) {
pptr = htab_elem_get_ptr(l_new, key_size);
} else {
/* alloc_percpu zero-fills */
pptr = bpf_mem_cache_alloc(&htab->pcpu_ma);
if (!pptr) {
bpf_mem_cache_free(&htab->ma, l_new);
l_new = ERR_PTR(-ENOMEM);
goto dec_count;
}
l_new->ptr_to_pptr = pptr;
pptr = *(void **)pptr;
}
pcpu_init_value(htab, pptr, value, onallcpus);
if (!prealloc)
htab_elem_set_ptr(l_new, key_size, pptr);
} else if (fd_htab_map_needs_adjust(htab)) {
size = round_up(size, 8);
memcpy(l_new->key + round_up(key_size, 8), value, size);
} else {
copy_map_value(&htab->map,
l_new->key + round_up(key_size, 8),
value);
}
l_new->hash = hash;
return l_new;
dec_count:
dec_elem_count(htab);
return l_new;
}
static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
u64 map_flags)
{
if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
/* elem already exists */
return -EEXIST;
if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
/* elem doesn't exist, cannot update it */
return -ENOENT;
return 0;
}
/* Called from syscall or from eBPF program */
static long htab_map_update_elem(struct bpf_map *map, void *key, void *value,
u64 map_flags)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new = NULL, *l_old;
struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
int ret;
if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
/* unknown flags */
return -EINVAL;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
key_size = map->key_size;
hash = htab_map_hash(key, key_size, htab->hashrnd);
b = __select_bucket(htab, hash);
head = &b->head;
if (unlikely(map_flags & BPF_F_LOCK)) {
if (unlikely(!btf_record_has_field(map->record, BPF_SPIN_LOCK)))
return -EINVAL;
/* find an element without taking the bucket lock */
l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
htab->n_buckets);
ret = check_flags(htab, l_old, map_flags);
if (ret)
return ret;
if (l_old) {
/* grab the element lock and update value in place */
copy_map_value_locked(map,
l_old->key + round_up(key_size, 8),
value, false);
return 0;
}
/* fall through, grab the bucket lock and lookup again.
* 99.9% chance that the element won't be found,
* but second lookup under lock has to be done.
*/
}
ret = htab_lock_bucket(htab, b, hash, &flags);
if (ret)
return ret;
l_old = lookup_elem_raw(head, hash, key, key_size);
ret = check_flags(htab, l_old, map_flags);
if (ret)
goto err;
if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
/* first lookup without the bucket lock didn't find the element,
* but second lookup with the bucket lock found it.
* This case is highly unlikely, but has to be dealt with:
* grab the element lock in addition to the bucket lock
* and update element in place
*/
copy_map_value_locked(map,
l_old->key + round_up(key_size, 8),
value, false);
ret = 0;
goto err;
}
l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
l_old);
if (IS_ERR(l_new)) {
/* all pre-allocated elements are in use or memory exhausted */
ret = PTR_ERR(l_new);
goto err;
}
/* add new element to the head of the list, so that
* concurrent search will find it before old elem
*/
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
if (l_old) {
hlist_nulls_del_rcu(&l_old->hash_node);
if (!htab_is_prealloc(htab))
free_htab_elem(htab, l_old);
else
check_and_free_fields(htab, l_old);
}
ret = 0;
err:
htab_unlock_bucket(htab, b, hash, flags);
return ret;
}
static void htab_lru_push_free(struct bpf_htab *htab, struct htab_elem *elem)
{
check_and_free_fields(htab, elem);
bpf_lru_push_free(&htab->lru, &elem->lru_node);
}
static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
u64 map_flags)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new, *l_old = NULL;
struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
int ret;
if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
key_size = map->key_size;
hash = htab_map_hash(key, key_size, htab->hashrnd);
b = __select_bucket(htab, hash);
head = &b->head;
/* For LRU, we need to alloc before taking bucket's
* spinlock because getting free nodes from LRU may need
* to remove older elements from htab and this removal
* operation will need a bucket lock.
*/
l_new = prealloc_lru_pop(htab, key, hash);
if (!l_new)
return -ENOMEM;
copy_map_value(&htab->map,
l_new->key + round_up(map->key_size, 8), value);
ret = htab_lock_bucket(htab, b, hash, &flags);
if (ret)
goto err_lock_bucket;
l_old = lookup_elem_raw(head, hash, key, key_size);
ret = check_flags(htab, l_old, map_flags);
if (ret)
goto err;
/* add new element to the head of the list, so that
* concurrent search will find it before old elem
*/
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
if (l_old) {
bpf_lru_node_set_ref(&l_new->lru_node);
hlist_nulls_del_rcu(&l_old->hash_node);
}
ret = 0;
err:
htab_unlock_bucket(htab, b, hash, flags);
err_lock_bucket:
if (ret)
htab_lru_push_free(htab, l_new);
else if (l_old)
htab_lru_push_free(htab, l_old);
return ret;
}
static long __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 map_flags,
bool onallcpus)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new = NULL, *l_old;
struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
int ret;
if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
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, &flags);
if (ret)
return ret;
l_old = lookup_elem_raw(head, hash, key, key_size);
ret = check_flags(htab, l_old, map_flags);
if (ret)
goto err;
if (l_old) {
/* per-cpu hash map can update value in-place */
pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
value, onallcpus);
} else {
l_new = alloc_htab_elem(htab, key, value, key_size,
hash, true, onallcpus, NULL);
if (IS_ERR(l_new)) {
ret = PTR_ERR(l_new);
goto err;
}
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
}
ret = 0;
err:
htab_unlock_bucket(htab, b, hash, flags);
return ret;
}
static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 map_flags,
bool onallcpus)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new = NULL, *l_old;
struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
int ret;
if (unlikely(map_flags > BPF_EXIST))
/* unknown flags */
return -EINVAL;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
key_size = map->key_size;
hash = htab_map_hash(key, key_size, htab->hashrnd);
b = __select_bucket(htab, hash);
head = &b->head;
/* For LRU, we need to alloc before taking bucket's
* spinlock because LRU's elem alloc may need
* to remove older elem from htab and this removal
* operation will need a bucket lock.
*/
if (map_flags != BPF_EXIST) {
l_new = prealloc_lru_pop(htab, key, hash);
if (!l_new)
return -ENOMEM;
}
ret = htab_lock_bucket(htab, b, hash, &flags);
if (ret)
goto err_lock_bucket;
l_old = lookup_elem_raw(head, hash, key, key_size);
ret = check_flags(htab, l_old, map_flags);
if (ret)
goto err;
if (l_old) {
bpf_lru_node_set_ref(&l_old->lru_node);
/* per-cpu hash map can update value in-place */
pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
value, onallcpus);
} else {
pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
value, onallcpus);
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
l_new = NULL;
}
ret = 0;
err:
htab_unlock_bucket(htab, b, hash, flags);
err_lock_bucket:
if (l_new)
bpf_lru_push_free(&htab->lru, &l_new->lru_node);
return ret;
}
static long htab_percpu_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 map_flags)
{
return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
}
static long htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 map_flags)
{
return __htab_lru_percpu_map_update_elem(map, key, value, map_flags,
false);
}
/* Called from syscall or from eBPF program */
static long htab_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_head *head;
struct bucket *b;
struct htab_elem *l;
unsigned long flags;
u32 hash, key_size;
int ret;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
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, &flags);
if (ret)
return ret;
l = lookup_elem_raw(head, hash, key, key_size);
if (l) {
hlist_nulls_del_rcu(&l->hash_node);
free_htab_elem(htab, l);
} else {
ret = -ENOENT;
}
htab_unlock_bucket(htab, b, hash, flags);
return ret;
}
static long htab_lru_map_delete_elem(struct bpf_map *map, void *key)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_head *head;
struct bucket *b;
struct htab_elem *l;
unsigned long flags;
u32 hash, key_size;
int ret;
WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() &&
!rcu_read_lock_bh_held());
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, &flags);
if (ret)
return ret;
l = lookup_elem_raw(head, hash, key, key_size);
if (l)
hlist_nulls_del_rcu(&l->hash_node);
else
ret = -ENOENT;
htab_unlock_bucket(htab, b, hash, flags);
if (l)
htab_lru_push_free(htab, l);
return ret;
}
static void delete_all_elements(struct bpf_htab *htab)
{
int i;
/* It's called from a worker thread, so disable migration here,
* since bpf_mem_cache_free() relies on that.
*/
migrate_disable();
for (i = 0; i < htab->n_buckets; i++) {
struct hlist_nulls_head *head = select_bucket(htab, i);
struct hlist_nulls_node *n;
struct htab_elem *l;
hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
hlist_nulls_del_rcu(&l->hash_node);
htab_elem_free(htab, l);
}
}
migrate_enable();
}
static void htab_free_malloced_timers(struct bpf_htab *htab)
{
int i;
rcu_read_lock();
for (i = 0; i < htab->n_buckets; i++) {
struct hlist_nulls_head *head = select_bucket(htab, i);
struct hlist_nulls_node *n;
struct htab_elem *l;
hlist_nulls_for_each_entry(l, n, head, hash_node) {
/* We only free timer on uref dropping to zero */
bpf_obj_free_timer(htab->map.record, l->key + round_up(htab->map.key_size, 8));
}
cond_resched_rcu();
}
rcu_read_unlock();
}
static void htab_map_free_timers(struct bpf_map *map)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
/* We only free timer on uref dropping to zero */
if (!btf_record_has_field(htab->map.record, BPF_TIMER))
return;
if (!htab_is_prealloc(htab))
htab_free_malloced_timers(htab);
else
htab_free_prealloced_timers(htab);
}
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
static void htab_map_free(struct bpf_map *map)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
int i;
/* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback.
* bpf_free_used_maps() is called after bpf prog is no longer executing.
* There is no need to synchronize_rcu() here to protect map elements.
*/
/* htab no longer uses call_rcu() directly. bpf_mem_alloc does it
* underneath and is reponsible for waiting for callbacks to finish
* during bpf_mem_alloc_destroy().
*/
if (!htab_is_prealloc(htab)) {
delete_all_elements(htab);
} else {
htab_free_prealloced_fields(htab);
prealloc_destroy(htab);
}
free_percpu(htab->extra_elems);
bpf_map_area_free(htab->buckets);
bpf_mem_alloc_destroy(&htab->pcpu_ma);
bpf_mem_alloc_destroy(&htab->ma);
if (htab->use_percpu_counter)
percpu_counter_destroy(&htab->pcount);
for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++)
free_percpu(htab->map_locked[i]);
lockdep_unregister_key(&htab->lockdep_key);
bpf_map_area_free(htab);
}
static void htab_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
void *value;
rcu_read_lock();
value = htab_map_lookup_elem(map, key);
if (!value) {
rcu_read_unlock();
return;
}
btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
seq_puts(m, ": ");
btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
seq_puts(m, "\n");
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) {
copy_map_value_long(&htab->map, value + off, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(&htab->map, value + off);
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);
/* Zeroing special fields in the temp buffer */
check_and_init_map_value(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)
htab_lru_push_free(htab, l);
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,
union bpf_attr __user *uattr,
bool do_delete, bool is_lru_map,
bool is_percpu)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
u32 bucket_cnt, total, key_size, value_size, roundup_key_size;
void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val;
void __user *uvalues = u64_to_user_ptr(attr->batch.values);
void __user *ukeys = u64_to_user_ptr(attr->batch.keys);
void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
u32 batch, max_count, size, bucket_size, map_id;
struct htab_elem *node_to_free = NULL;
u64 elem_map_flags, map_flags;
struct hlist_nulls_head *head;
struct hlist_nulls_node *n;
unsigned long flags = 0;
bool locked = false;
struct htab_elem *l;
struct bucket *b;
int ret = 0;
elem_map_flags = attr->batch.elem_flags;
if ((elem_map_flags & ~BPF_F_LOCK) ||
((elem_map_flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
return -EINVAL;
map_flags = attr->batch.flags;
if (map_flags)
return -EINVAL;
max_count = attr->batch.count;
if (!max_count)
return 0;
if (put_user(0, &uattr->batch.count))
return -EFAULT;
batch = 0;
if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch)))
return -EFAULT;
if (batch >= htab->n_buckets)
return -ENOENT;
key_size = htab->map.key_size;
roundup_key_size = round_up(htab->map.key_size, 8);
value_size = htab->map.value_size;
size = round_up(value_size, 8);
if (is_percpu)
value_size = size * num_possible_cpus();
total = 0;
/* while experimenting with hash tables with sizes ranging from 10 to
* 1000, it was observed that a bucket can have up to 5 entries.
*/
bucket_size = 5;
alloc:
/* We cannot do copy_from_user or copy_to_user inside
* the rcu_read_lock. Allocate enough space here.
*/
keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN);
values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN);
if (!keys || !values) {
ret = -ENOMEM;
goto after_loop;
}
again:
bpf_disable_instrumentation();
rcu_read_lock();
again_nocopy:
dst_key = keys;
dst_val = values;
b = &htab->buckets[batch];
head = &b->head;
/* do not grab the lock unless need it (bucket_cnt > 0). */
if (locked) {
ret = htab_lock_bucket(htab, b, batch, &flags);
if (ret) {
rcu_read_unlock();
bpf_enable_instrumentation();
goto after_loop;
}
}
bucket_cnt = 0;
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
bucket_cnt++;
if (bucket_cnt && !locked) {
locked = true;
goto again_nocopy;
}
if (bucket_cnt > (max_count - total)) {
if (total == 0)
ret = -ENOSPC;
/* Note that since bucket_cnt > 0 here, it is implicit
* that the locked was grabbed, so release it.
*/
htab_unlock_bucket(htab, b, batch, flags);
rcu_read_unlock();
bpf_enable_instrumentation();
goto after_loop;
}
if (bucket_cnt > bucket_size) {
bucket_size = bucket_cnt;
/* Note that since bucket_cnt > 0 here, it is implicit
* that the locked was grabbed, so release it.
*/
htab_unlock_bucket(htab, b, batch, flags);
rcu_read_unlock();
bpf_enable_instrumentation();
kvfree(keys);
kvfree(values);
goto alloc;
}
/* Next block is only safe to run if you have grabbed the lock */
if (!locked)
goto next_batch;
hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
memcpy(dst_key, l->key, key_size);
if (is_percpu) {
int off = 0, cpu;
void __percpu *pptr;
pptr = htab_elem_get_ptr(l, map->key_size);
for_each_possible_cpu(cpu) {
copy_map_value_long(&htab->map, dst_val + off, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(&htab->map, dst_val + off);
off += size;
}
} else {
value = l->key + roundup_key_size;
if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
struct bpf_map **inner_map = value;
/* Actual value is the id of the inner map */
map_id = map->ops->map_fd_sys_lookup_elem(*inner_map);
value = &map_id;
}
if (elem_map_flags & BPF_F_LOCK)
copy_map_value_locked(map, dst_val, value,
true);
else
copy_map_value(map, dst_val, value);
/* Zeroing special fields in the temp buffer */
check_and_init_map_value(map, dst_val);
}
if (do_delete) {
hlist_nulls_del_rcu(&l->hash_node);
/* bpf_lru_push_free() will acquire lru_lock, which
* may cause deadlock. See comments in function
* prealloc_lru_pop(). Let us do bpf_lru_push_free()
* after releasing the bucket lock.
*/
if (is_lru_map) {
l->batch_flink = node_to_free;
node_to_free = l;
} else {
free_htab_elem(htab, l);
}
}
dst_key += key_size;
dst_val += value_size;
}
htab_unlock_bucket(htab, b, batch, flags);
locked = false;
while (node_to_free) {
l = node_to_free;
node_to_free = node_to_free->batch_flink;
htab_lru_push_free(htab, l);
}
next_batch:
/* If we are not copying data, we can go to next bucket and avoid
* unlocking the rcu.
*/
if (!bucket_cnt && (batch + 1 < htab->n_buckets)) {
batch++;
goto again_nocopy;
}
rcu_read_unlock();
bpf_enable_instrumentation();
if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys,
key_size * bucket_cnt) ||
copy_to_user(uvalues + total * value_size, values,
value_size * bucket_cnt))) {
ret = -EFAULT;
goto after_loop;
}
total += bucket_cnt;
batch++;
if (batch >= htab->n_buckets) {
ret = -ENOENT;
goto after_loop;
}
goto again;
after_loop:
if (ret == -EFAULT)
goto out;
/* copy # of entries and next batch */
ubatch = u64_to_user_ptr(attr->batch.out_batch);
if (copy_to_user(ubatch, &batch, sizeof(batch)) ||
put_user(total, &uattr->batch.count))
ret = -EFAULT;
out:
kvfree(keys);
kvfree(values);
return ret;
}
static int
htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
false, true);
}
static int
htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
false, true);
}
static int
htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
false, false);
}
static int
htab_map_lookup_and_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
false, false);
}
static int
htab_lru_percpu_map_lookup_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
true, true);
}
static int
htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
true, true);
}
static int
htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, false,
true, false);
}
static int
htab_lru_map_lookup_and_delete_batch(struct bpf_map *map,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
return __htab_map_lookup_and_delete_batch(map, attr, uattr, true,
true, false);
}
struct bpf_iter_seq_hash_map_info {
struct bpf_map *map;
struct bpf_htab *htab;
void *percpu_value_buf; // non-zero means percpu hash
u32 bucket_id;
u32 skip_elems;
};
static struct htab_elem *
bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info,
struct htab_elem *prev_elem)
{
const struct bpf_htab *htab = info->htab;
u32 skip_elems = info->skip_elems;
u32 bucket_id = info->bucket_id;
struct hlist_nulls_head *head;
struct hlist_nulls_node *n;
struct htab_elem *elem;
struct bucket *b;
u32 i, count;
if (bucket_id >= htab->n_buckets)
return NULL;
/* try to find next elem in the same bucket */
if (prev_elem) {
/* no update/deletion on this bucket, prev_elem should be still valid
* and we won't skip elements.
*/
n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node));
elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node);
if (elem)
return elem;
/* not found, unlock and go to the next bucket */
b = &htab->buckets[bucket_id++];
rcu_read_unlock();
skip_elems = 0;
}
for (i = bucket_id; i < htab->n_buckets; i++) {
b = &htab->buckets[i];
rcu_read_lock();
count = 0;
head = &b->head;
hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
if (count >= skip_elems) {
info->bucket_id = i;
info->skip_elems = count;
return elem;
}
count++;
}
rcu_read_unlock();
skip_elems = 0;
}
info->bucket_id = i;
info->skip_elems = 0;
return NULL;
}
static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos)
{
struct bpf_iter_seq_hash_map_info *info = seq->private;
struct htab_elem *elem;
elem = bpf_hash_map_seq_find_next(info, NULL);
if (!elem)
return NULL;
if (*pos == 0)
++*pos;
return elem;
}
static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct bpf_iter_seq_hash_map_info *info = seq->private;
++*pos;
++info->skip_elems;
return bpf_hash_map_seq_find_next(info, v);
}
static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem)
{
struct bpf_iter_seq_hash_map_info *info = seq->private;
u32 roundup_key_size, roundup_value_size;
struct bpf_iter__bpf_map_elem ctx = {};
struct bpf_map *map = info->map;
struct bpf_iter_meta meta;
int ret = 0, off = 0, cpu;
struct bpf_prog *prog;
void __percpu *pptr;
meta.seq = seq;
prog = bpf_iter_get_info(&meta, elem == NULL);
if (prog) {
ctx.meta = &meta;
ctx.map = info->map;
if (elem) {
roundup_key_size = round_up(map->key_size, 8);
ctx.key = elem->key;
if (!info->percpu_value_buf) {
ctx.value = elem->key + roundup_key_size;
} else {
roundup_value_size = round_up(map->value_size, 8);
pptr = htab_elem_get_ptr(elem, map->key_size);
for_each_possible_cpu(cpu) {
copy_map_value_long(map, info->percpu_value_buf + off,
per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, info->percpu_value_buf + off);
off += roundup_value_size;
}
ctx.value = info->percpu_value_buf;
}
}
ret = bpf_iter_run_prog(prog, &ctx);
}
return ret;
}
static int bpf_hash_map_seq_show(struct seq_file *seq, void *v)
{
return __bpf_hash_map_seq_show(seq, v);
}
static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v)
{
if (!v)
(void)__bpf_hash_map_seq_show(seq, NULL);
else
rcu_read_unlock();
}
static int bpf_iter_init_hash_map(void *priv_data,
struct bpf_iter_aux_info *aux)
{
struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
struct bpf_map *map = aux->map;
void *value_buf;
u32 buf_size;
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
buf_size = round_up(map->value_size, 8) * num_possible_cpus();
value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
if (!value_buf)
return -ENOMEM;
seq_info->percpu_value_buf = value_buf;
}
bpf_map_inc_with_uref(map);
seq_info->map = map;
seq_info->htab = container_of(map, struct bpf_htab, map);
return 0;
}
static void bpf_iter_fini_hash_map(void *priv_data)
{
struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
bpf_map_put_with_uref(seq_info->map);
kfree(seq_info->percpu_value_buf);
}
static const struct seq_operations bpf_hash_map_seq_ops = {
.start = bpf_hash_map_seq_start,
.next = bpf_hash_map_seq_next,
.stop = bpf_hash_map_seq_stop,
.show = bpf_hash_map_seq_show,
};
static const struct bpf_iter_seq_info iter_seq_info = {
.seq_ops = &bpf_hash_map_seq_ops,
.init_seq_private = bpf_iter_init_hash_map,
.fini_seq_private = bpf_iter_fini_hash_map,
.seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info),
};
static long bpf_for_each_hash_elem(struct bpf_map *map, bpf_callback_t callback_fn,
void *callback_ctx, u64 flags)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_head *head;
struct hlist_nulls_node *n;
struct htab_elem *elem;
u32 roundup_key_size;
int i, num_elems = 0;
void __percpu *pptr;
struct bucket *b;
void *key, *val;
bool is_percpu;
u64 ret = 0;
if (flags != 0)
return -EINVAL;
is_percpu = htab_is_percpu(htab);
roundup_key_size = round_up(map->key_size, 8);
/* disable migration so percpu value prepared here will be the
* same as the one seen by the bpf program with bpf_map_lookup_elem().
*/
if (is_percpu)
migrate_disable();
for (i = 0; i < htab->n_buckets; i++) {
b = &htab->buckets[i];
rcu_read_lock();
head = &b->head;
hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) {
key = elem->key;
if (is_percpu) {
/* current cpu value for percpu map */
pptr = htab_elem_get_ptr(elem, map->key_size);
val = this_cpu_ptr(pptr);
} else {
val = elem->key + roundup_key_size;
}
num_elems++;
ret = callback_fn((u64)(long)map, (u64)(long)key,
(u64)(long)val, (u64)(long)callback_ctx, 0);
/* return value: 0 - continue, 1 - stop and return */
if (ret) {
rcu_read_unlock();
goto out;
}
}
rcu_read_unlock();
}
out:
if (is_percpu)
migrate_enable();
return num_elems;
}
static u64 htab_map_mem_usage(const struct bpf_map *map)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
u32 value_size = round_up(htab->map.value_size, 8);
bool prealloc = htab_is_prealloc(htab);
bool percpu = htab_is_percpu(htab);
bool lru = htab_is_lru(htab);
u64 num_entries;
u64 usage = sizeof(struct bpf_htab);
usage += sizeof(struct bucket) * htab->n_buckets;
usage += sizeof(int) * num_possible_cpus() * HASHTAB_MAP_LOCK_COUNT;
if (prealloc) {
num_entries = map->max_entries;
if (htab_has_extra_elems(htab))
num_entries += num_possible_cpus();
usage += htab->elem_size * num_entries;
if (percpu)
usage += value_size * num_possible_cpus() * num_entries;
else if (!lru)
usage += sizeof(struct htab_elem *) * num_possible_cpus();
} else {
#define LLIST_NODE_SZ sizeof(struct llist_node)
num_entries = htab->use_percpu_counter ?
percpu_counter_sum(&htab->pcount) :
atomic_read(&htab->count);
usage += (htab->elem_size + LLIST_NODE_SZ) * num_entries;
if (percpu) {
usage += (LLIST_NODE_SZ + sizeof(void *)) * num_entries;
usage += value_size * num_possible_cpus() * num_entries;
}
}
return usage;
}
BTF_ID_LIST_SINGLE(htab_map_btf_ids, struct, bpf_htab)
const struct bpf_map_ops htab_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = htab_map_alloc_check,
.map_alloc = htab_map_alloc,
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_release_uref = htab_map_free_timers,
.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,
.map_seq_show_elem = htab_map_seq_show_elem,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_hash_elem,
.map_mem_usage = htab_map_mem_usage,
BATCH_OPS(htab),
.map_btf_id = &htab_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
const struct bpf_map_ops htab_lru_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = htab_map_alloc_check,
.map_alloc = htab_map_alloc,
.map_free = htab_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_release_uref = htab_map_free_timers,
.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,
.map_gen_lookup = htab_lru_map_gen_lookup,
.map_seq_show_elem = htab_map_seq_show_elem,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_hash_elem,
.map_mem_usage = htab_map_mem_usage,
BATCH_OPS(htab_lru),
.map_btf_id = &htab_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
/* Called from eBPF program */
static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
{
struct htab_elem *l = __htab_map_lookup_elem(map, key);
if (l)
return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
else
return NULL;
}
static void *htab_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
{
struct htab_elem *l;
if (cpu >= nr_cpu_ids)
return NULL;
l = __htab_map_lookup_elem(map, key);
if (l)
return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
else
return NULL;
}
static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key)
{
struct htab_elem *l = __htab_map_lookup_elem(map, key);
if (l) {
bpf_lru_node_set_ref(&l->lru_node);
return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
}
return NULL;
}
static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
{
struct htab_elem *l;
if (cpu >= nr_cpu_ids)
return NULL;
l = __htab_map_lookup_elem(map, key);
if (l) {
bpf_lru_node_set_ref(&l->lru_node);
return per_cpu_ptr(htab_elem_get_ptr(l, map->key_size), cpu);
}
return NULL;
}
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
{
struct htab_elem *l;
void __percpu *pptr;
int ret = -ENOENT;
int cpu, off = 0;
u32 size;
/* per_cpu areas are zero-filled and bpf programs can only
* access 'value_size' of them, so copying rounded areas
* will not leak any kernel data
*/
size = round_up(map->value_size, 8);
rcu_read_lock();
l = __htab_map_lookup_elem(map, key);
if (!l)
goto out;
/* We do not mark LRU map element here in order to not mess up
* eviction heuristics when user space does a map walk.
*/
pptr = htab_elem_get_ptr(l, map->key_size);
for_each_possible_cpu(cpu) {
copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, value + off);
off += size;
}
ret = 0;
out:
rcu_read_unlock();
return ret;
}
int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
u64 map_flags)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
int ret;
rcu_read_lock();
if (htab_is_lru(htab))
ret = __htab_lru_percpu_map_update_elem(map, key, value,
map_flags, true);
else
ret = __htab_percpu_map_update_elem(map, key, value, map_flags,
true);
rcu_read_unlock();
return ret;
}
static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
struct seq_file *m)
{
struct htab_elem *l;
void __percpu *pptr;
int cpu;
rcu_read_lock();
l = __htab_map_lookup_elem(map, key);
if (!l) {
rcu_read_unlock();
return;
}
btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
seq_puts(m, ": {\n");
pptr = htab_elem_get_ptr(l, map->key_size);
for_each_possible_cpu(cpu) {
seq_printf(m, "\tcpu%d: ", cpu);
btf_type_seq_show(map->btf, map->btf_value_type_id,
per_cpu_ptr(pptr, cpu), m);
seq_puts(m, "\n");
}
seq_puts(m, "}\n");
rcu_read_unlock();
}
const struct bpf_map_ops htab_percpu_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = htab_map_alloc_check,
.map_alloc = htab_map_alloc,
.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_lookup_percpu_elem = htab_percpu_map_lookup_percpu_elem,
.map_seq_show_elem = htab_percpu_map_seq_show_elem,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_hash_elem,
.map_mem_usage = htab_map_mem_usage,
BATCH_OPS(htab_percpu),
.map_btf_id = &htab_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
const struct bpf_map_ops htab_lru_percpu_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = htab_map_alloc_check,
.map_alloc = htab_map_alloc,
.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_lookup_percpu_elem = htab_lru_percpu_map_lookup_percpu_elem,
.map_seq_show_elem = htab_percpu_map_seq_show_elem,
.map_set_for_each_callback_args = map_set_for_each_callback_args,
.map_for_each_callback = bpf_for_each_hash_elem,
.map_mem_usage = htab_map_mem_usage,
BATCH_OPS(htab_lru_percpu),
.map_btf_id = &htab_map_btf_ids[0],
.iter_seq_info = &iter_seq_info,
};
static int fd_htab_map_alloc_check(union bpf_attr *attr)
{
if (attr->value_size != sizeof(u32))
return -EINVAL;
return htab_map_alloc_check(attr);
}
static void fd_htab_map_free(struct bpf_map *map)
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct hlist_nulls_node *n;
struct hlist_nulls_head *head;
struct htab_elem *l;
int i;
for (i = 0; i < htab->n_buckets; i++) {
head = select_bucket(htab, i);
hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
void *ptr = fd_htab_map_get_ptr(map, l);
map->ops->map_fd_put_ptr(ptr);
}
}
htab_map_free(map);
}
/* only called from syscall */
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
{
void **ptr;
int ret = 0;
if (!map->ops->map_fd_sys_lookup_elem)
return -ENOTSUPP;
rcu_read_lock();
ptr = htab_map_lookup_elem(map, key);
if (ptr)
*value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr));
else
ret = -ENOENT;
rcu_read_unlock();
return ret;
}
/* only called from syscall */
int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
void *key, void *value, u64 map_flags)
{
void *ptr;
int ret;
u32 ufd = *(u32 *)value;
ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
ret = htab_map_update_elem(map, key, &ptr, map_flags);
if (ret)
map->ops->map_fd_put_ptr(ptr);
return ret;
}
static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
{
struct bpf_map *map, *inner_map_meta;
inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
if (IS_ERR(inner_map_meta))
return inner_map_meta;
map = htab_map_alloc(attr);
if (IS_ERR(map)) {
bpf_map_meta_free(inner_map_meta);
return map;
}
map->inner_map_meta = inner_map_meta;
return map;
}
static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
{
struct bpf_map **inner_map = htab_map_lookup_elem(map, key);
if (!inner_map)
return NULL;
return READ_ONCE(*inner_map);
}
static int htab_of_map_gen_lookup(struct bpf_map *map,
struct bpf_insn *insn_buf)
{
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem,
(void *(*)(struct bpf_map *map, void *key))NULL));
*insn++ = BPF_EMIT_CALL(__htab_map_lookup_elem);
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2);
*insn++ = BPF_ALU64_IMM(BPF_ADD, ret,
offsetof(struct htab_elem, key) +
round_up(map->key_size, 8));
*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
return insn - insn_buf;
}
static void htab_of_map_free(struct bpf_map *map)
{
bpf_map_meta_free(map->inner_map_meta);
fd_htab_map_free(map);
}
const struct bpf_map_ops htab_of_maps_map_ops = {
.map_alloc_check = fd_htab_map_alloc_check,
.map_alloc = htab_of_map_alloc,
.map_free = htab_of_map_free,
.map_get_next_key = htab_map_get_next_key,
.map_lookup_elem = htab_of_map_lookup_elem,
.map_delete_elem = htab_map_delete_elem,
.map_fd_get_ptr = bpf_map_fd_get_ptr,
.map_fd_put_ptr = bpf_map_fd_put_ptr,
.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
.map_gen_lookup = htab_of_map_gen_lookup,
.map_check_btf = map_check_no_btf,
.map_mem_usage = htab_map_mem_usage,
BATCH_OPS(htab),
.map_btf_id = &htab_map_btf_ids[0],
};