/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com

* Copyright (c) 2016 Facebook

*

* This program is free software; you can redistribute it and/or

* modify it under the terms of version 2 of the GNU General Public

* License as published by the Free Software Foundation.

*

* This program is distributed in the hope that it will be useful, but

* WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

* General Public License for more details.

*/

#include <linux/bpf.h>

#include <linux/jhash.h>

#include <linux/filter.h>

#include <linux/rculist_nulls.h>

#include "percpu_freelist.h"

#include "bpf_lru_list.h"

#include "map_in_map.h"

#define HTAB_CREATE_FLAG_MASK \

(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE)

struct bucket {

struct hlist_nulls_head head;

raw_spinlock_t lock;

};

struct bpf_htab {

struct bpf_map map;

struct bucket *buckets;

void *elems;

union {

struct pcpu_freelist freelist;

struct bpf_lru lru;

};

struct htab_elem *__percpu *extra_elems;

atomic_t count; /* number of elements in this hashtable */

u32 n_buckets; /* number of hash buckets */

u32 elem_size; /* size of each element in bytes */

};

/* each htab element is struct htab_elem + key + value */

struct htab_elem {

union {

struct hlist_nulls_node hash_node;

struct {

void *padding;

union {

struct bpf_htab *htab;

struct pcpu_freelist_node fnode;

};

};

};

union {

struct rcu_head rcu;

struct bpf_lru_node lru_node;

};

u32 hash;

char key[0] __aligned(8);

};

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 bool htab_is_prealloc(const struct bpf_htab *htab)

{

return !(htab->map.map_flags & BPF_F_NO_PREALLOC);

}

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 * htab->elem_size);

}

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);

}

free_elems:

bpf_map_area_free(htab->elems);

}

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_is_percpu(htab) && !htab_is_lru(htab))

num_entries += num_possible_cpus();

htab->elems = bpf_map_area_alloc(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 = __alloc_percpu_gfp(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);

}

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 = __alloc_percpu_gfp(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 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);

int numa_node = bpf_map_attr_numa_node(attr);

struct bpf_htab *htab;

int err, i;

u64 cost;

BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=

offsetof(struct htab_elem, hash_node.pprev));

BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=

offsetof(struct htab_elem, hash_node.pprev));

if (lru && !capable(CAP_SYS_ADMIN))

/* LRU implementation is much complicated than other

* maps. Hence, limit to CAP_SYS_ADMIN for now.

*/

return ERR_PTR(-EPERM);

if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)

/* reserved bits should not be used */

return ERR_PTR(-EINVAL);

if (!lru && percpu_lru)

return ERR_PTR(-EINVAL);

if (lru && !prealloc)

return ERR_PTR(-ENOTSUPP);

if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))

return ERR_PTR(-EINVAL);

htab = kzalloc(sizeof(*htab), GFP_USER);

if (!htab)

return ERR_PTR(-ENOMEM);

/* mandatory map attributes */

htab->map.map_type = attr->map_type;

htab->map.key_size = attr->key_size;

htab->map.value_size = attr->value_size;

htab->map.max_entries = attr->max_entries;

htab->map.map_flags = attr->map_flags;

htab->map.numa_node = numa_node;

/* check sanity of attributes.

* value_size == 0 may be allowed in the future to use map as a set

*/

err = -EINVAL;

if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||

htab->map.value_size == 0)

goto free_htab;

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);

err = -E2BIG;

if (htab->map.key_size > MAX_BPF_STACK)

/* eBPF programs initialize keys on stack, so they cannot be

* larger than max stack size

*/

goto free_htab;

if (htab->map.value_size >= KMALLOC_MAX_SIZE -

MAX_BPF_STACK - sizeof(struct htab_elem))

/* if 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()

*/

goto free_htab;

if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE)

/* make sure the size for pcpu_alloc() is reasonable */

goto free_htab;

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);

/* 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;

cost = (u64) htab->n_buckets * sizeof(struct bucket) +

(u64) htab->elem_size * htab->map.max_entries;

if (percpu)

cost += (u64) round_up(htab->map.value_size, 8) *

num_possible_cpus() * htab->map.max_entries;

else

cost += (u64) htab->elem_size * num_possible_cpus();

if (cost >= U32_MAX - PAGE_SIZE)

/* make sure page count doesn't overflow */

goto free_htab;

htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;

/* if map size is larger than memlock limit, reject it early */

err = bpf_map_precharge_memlock(htab->map.pages);

if (err)

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 < htab->n_buckets; i++) {

INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);

raw_spin_lock_init(&htab->buckets[i].lock);

}

if (prealloc) {

err = prealloc_init(htab);

if (err)

goto free_buckets;

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;

}

}

return &htab->map;

free_prealloc:

prealloc_destroy(htab);

free_buckets:

bpf_map_area_free(htab->buckets);

free_htab:

kfree(htab);

return ERR_PTR(err);

}

static inline u32 htab_map_hash(const void *key, u32 key_len)

{

return jhash(key, key_len, 0);

}

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;

/* Must be called with rcu_read_lock. */

WARN_ON_ONCE(!rcu_read_lock_held());

key_size = map->key_size;

hash = htab_map_hash(key, key_size);

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 u32 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;

*insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__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 void *htab_lru_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 l->key + round_up(map->key_size, 8);

}

return NULL;

}

static u32 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;

*insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__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;

}

/* 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 = (struct bpf_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;

tgt_l = container_of(node, struct htab_elem, lru_node);

b = __select_bucket(htab, tgt_l->hash);

head = &b->head;

raw_spin_lock_irqsave(&b->lock, flags);

hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)

if (l == tgt_l) {

hlist_nulls_del_rcu(&l->hash_node);

break;

}

raw_spin_unlock_irqrestore(&b->lock, 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);

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)

{

if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH)

free_percpu(htab_elem_get_ptr(l, htab->map.key_size));

kfree(l);

}

static void htab_elem_free_rcu(struct rcu_head *head)

{

struct htab_elem *l = container_of(head, struct htab_elem, rcu);

struct bpf_htab *htab = l->htab;

/* must increment bpf_prog_active to avoid kprobe+bpf triggering while

* we're calling kfree, otherwise deadlock is possible if kprobes

* are placed somewhere inside of slub

*/

preempt_disable();

__this_cpu_inc(bpf_prog_active);

htab_elem_free(htab, l);

__this_cpu_dec(bpf_prog_active);

preempt_enable();

}

static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)

{

struct bpf_map *map = &htab->map;

if (map->ops->map_fd_put_ptr) {

void *ptr = fd_htab_map_get_ptr(map, l);

map->ops->map_fd_put_ptr(ptr);

}

if (htab_is_prealloc(htab)) {

pcpu_freelist_push(&htab->freelist, &l->fnode);

} else {

atomic_dec(&htab->count);

l->htab = htab;

call_rcu(&l->rcu, htab_elem_free_rcu);

}

}

static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,

void *value, bool onallcpus)

{

if (!onallcpus) {

/* copy true value_size bytes */

memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);

} else {

u32 size = round_up(htab->map.value_size, 8);

int off = 0, cpu;

for_each_possible_cpu(cpu) {

bpf_long_memcpy(per_cpu_ptr(pptr, cpu),

value + off, size);

off += size;

}

}

}

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 u32 htab_size_value(const struct bpf_htab *htab, bool percpu)

{

u32 size = htab->map.value_size;

if (percpu || fd_htab_map_needs_adjust(htab))

size = round_up(size, 8);

return size;

}

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_size_value(htab, percpu);

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;

*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 (atomic_inc_return(&htab->count) > htab->map.max_entries)

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

*/

atomic_dec(&htab->count);

return ERR_PTR(-E2BIG);

}

l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,

htab->map.numa_node);

if (!l_new)

return ERR_PTR(-ENOMEM);

}

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 = __alloc_percpu_gfp(size, 8,

GFP_ATOMIC | __GFP_NOWARN);

if (!pptr) {

kfree(l_new);

return ERR_PTR(-ENOMEM);

}

}

pcpu_copy_value(htab, pptr, value, onallcpus);

if (!prealloc)

htab_elem_set_ptr(l_new, key_size, pptr);

} else {

memcpy(l_new->key + round_up(key_size, 8), value, size);

}

l_new->hash = hash;

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_NOEXIST)

/* elem already exists */

return -EEXIST;

if (!l_old && map_flags == BPF_EXIST)

/* elem doesn't exist, cannot update it */

return -ENOENT;

return 0;

}

/* Called from syscall or from eBPF program */

static int 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_EXIST))

/* unknown flags */

return -EINVAL;

WARN_ON_ONCE(!rcu_read_lock_held());

key_size = map->key_size;

hash = htab_map_hash(key, key_size);

b = __select_bucket(htab, hash);

head = &b->head;

/* bpf_map_update_elem() can be called in_irq() */

raw_spin_lock_irqsave(&b->lock, flags);

l_old = lookup_elem_raw(head, hash, key, key_size);

ret = check_flags(htab, l_old, map_flags);

if (ret)

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);

}

ret = 0;

err:

raw_spin_unlock_irqrestore(&b->lock, flags);

return ret;

}

static int 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());

key_size = map->key_size;

hash = htab_map_hash(key, key_size);

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;

memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);

/* bpf_map_update_elem() can be called in_irq() */

raw_spin_lock_irqsave(&b->lock, flags);

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:

raw_spin_unlock_irqrestore(&b->lock, flags);

if (ret)

bpf_lru_push_free(&htab->lru, &l_new->lru_node);

else if (l_old)

bpf_lru_push_free(&htab->lru, &l_old->lru_node);

return ret;

}

static int __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());

key_size = map->key_size;

hash = htab_map_hash(key, key_size);

b = __select_bucket(htab, hash);

head = &b->head;

/* bpf_map_update_elem() can be called in_irq() */

raw_spin_lock_irqsave(&b->lock, flags);

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:

raw_spin_unlock_irqrestore(&b->lock, flags);

return ret;

}

static int __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());

key_size = map->key_size;

hash = htab_map_hash(key, key_size);

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;

}

/* bpf_map_update_elem() can be called in_irq() */

raw_spin_lock_irqsave(&b->lock, flags);

l_old = lookup_elem_raw(head, hash, key, key_size);