| /* 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 "percpu_freelist.h" |
| #define HTAB_CREATE_FLAG_MASK \ |
| (BPF_F_NO_PREALLOC | BPF_F_RDONLY | BPF_F_WRONLY) |
| |
| struct bucket { |
| struct hlist_head head; |
| raw_spinlock_t lock; |
| }; |
| |
| struct bpf_htab { |
| struct bpf_map map; |
| struct bucket *buckets; |
| void *elems; |
| struct pcpu_freelist freelist; |
| void __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 */ |
| }; |
| |
| enum extra_elem_state { |
| HTAB_NOT_AN_EXTRA_ELEM = 0, |
| HTAB_EXTRA_ELEM_FREE, |
| HTAB_EXTRA_ELEM_USED |
| }; |
| |
| /* each htab element is struct htab_elem + key + value */ |
| struct htab_elem { |
| union { |
| struct hlist_node hash_node; |
| struct bpf_htab *htab; |
| struct pcpu_freelist_node fnode; |
| }; |
| union { |
| struct rcu_head rcu; |
| enum extra_elem_state state; |
| }; |
| u32 hash; |
| char key[0] __aligned(8); |
| }; |
| |
| 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 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->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) |
| 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 int prealloc_elems_and_freelist(struct bpf_htab *htab) |
| { |
| int err = -ENOMEM, i; |
| |
| htab->elems = bpf_map_area_alloc(htab->elem_size * |
| htab->map.max_entries); |
| if (!htab->elems) |
| return -ENOMEM; |
| |
| if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH) |
| goto skip_percpu_elems; |
| |
| for (i = 0; i < htab->map.max_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: |
| err = pcpu_freelist_init(&htab->freelist); |
| if (err) |
| goto free_elems; |
| |
| pcpu_freelist_populate(&htab->freelist, htab->elems, htab->elem_size, |
| htab->map.max_entries); |
| return 0; |
| |
| free_elems: |
| htab_free_elems(htab); |
| return err; |
| } |
| |
| static int alloc_extra_elems(struct bpf_htab *htab) |
| { |
| void __percpu *pptr; |
| int cpu; |
| |
| pptr = __alloc_percpu_gfp(htab->elem_size, 8, GFP_USER | __GFP_NOWARN); |
| if (!pptr) |
| return -ENOMEM; |
| |
| for_each_possible_cpu(cpu) { |
| ((struct htab_elem *)per_cpu_ptr(pptr, cpu))->state = |
| HTAB_EXTRA_ELEM_FREE; |
| } |
| 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; |
| struct bpf_htab *htab; |
| int err, i; |
| u64 cost; |
| |
| if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK) |
| /* reserved bits should not be used */ |
| 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; |
| |
| /* 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; |
| |
| /* 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 >= (1 << (KMALLOC_SHIFT_MAX - 1)) - |
| 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)); |
| if (!htab->buckets) |
| goto free_htab; |
| |
| for (i = 0; i < htab->n_buckets; i++) { |
| INIT_HLIST_HEAD(&htab->buckets[i].head); |
| raw_spin_lock_init(&htab->buckets[i].lock); |
| } |
| |
| if (!percpu) { |
| err = alloc_extra_elems(htab); |
| if (err) |
| goto free_buckets; |
| } |
| |
| if (!(attr->map_flags & BPF_F_NO_PREALLOC)) { |
| err = prealloc_elems_and_freelist(htab); |
| if (err) |
| goto free_extra_elems; |
| } |
| |
| return &htab->map; |
| |
| free_extra_elems: |
| free_percpu(htab->extra_elems); |
| 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_head *select_bucket(struct bpf_htab *htab, u32 hash) |
| { |
| return &__select_bucket(htab, hash)->head; |
| } |
| |
| static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash, |
| void *key, u32 key_size) |
| { |
| struct htab_elem *l; |
| |
| hlist_for_each_entry_rcu(l, head, hash_node) |
| if (l->hash == hash && !memcmp(&l->key, key, key_size)) |
| return l; |
| |
| return NULL; |
| } |
| |
| /* Called from syscall or from eBPF program */ |
| 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_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_elem_raw(head, hash, key, key_size); |
| |
| 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; |
| } |
| |
| /* 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_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_elem_raw(head, hash, key, key_size); |
| |
| if (!l) |
| goto find_first_elem; |
| |
| /* key was found, get next key in the same bucket */ |
| next_l = hlist_entry_safe(rcu_dereference_raw(hlist_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_entry_safe(rcu_dereference_raw(hlist_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) |
| { |
| if (l->state == HTAB_EXTRA_ELEM_USED) { |
| l->state = HTAB_EXTRA_ELEM_FREE; |
| return; |
| } |
| |
| if (!(htab->map.map_flags & BPF_F_NO_PREALLOC)) { |
| pcpu_freelist_push(&htab->freelist, &l->fnode); |
| } else { |
| atomic_dec(&htab->count); |
| l->htab = htab; |
| call_rcu(&l->rcu, htab_elem_free_rcu); |
| } |
| } |
| |
| static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, |
| void *value, u32 key_size, u32 hash, |
| bool percpu, bool onallcpus, |
| bool old_elem_exists) |
| { |
| u32 size = htab->map.value_size; |
| bool prealloc = !(htab->map.map_flags & BPF_F_NO_PREALLOC); |
| struct htab_elem *l_new; |
| void __percpu *pptr; |
| int err = 0; |
| |
| if (prealloc) { |
| l_new = (struct htab_elem *)pcpu_freelist_pop(&htab->freelist); |
| if (!l_new) |
| err = -E2BIG; |
| } else { |
| if (atomic_inc_return(&htab->count) > htab->map.max_entries) { |
| atomic_dec(&htab->count); |
| err = -E2BIG; |
| } else { |
| l_new = kmalloc(htab->elem_size, |
| GFP_ATOMIC | __GFP_NOWARN); |
| if (!l_new) |
| return ERR_PTR(-ENOMEM); |
| } |
| } |
| |
| if (err) { |
| if (!old_elem_exists) |
| return ERR_PTR(err); |
| |
| /* if we're updating the existing element and the hash table |
| * is full, use per-cpu extra elems |
| */ |
| l_new = this_cpu_ptr(htab->extra_elems); |
| if (l_new->state != HTAB_EXTRA_ELEM_FREE) |
| return ERR_PTR(-E2BIG); |
| l_new->state = HTAB_EXTRA_ELEM_USED; |
| } else { |
| l_new->state = HTAB_NOT_AN_EXTRA_ELEM; |
| } |
| |
| memcpy(l_new->key, key, key_size); |
| if (percpu) { |
| /* round up value_size to 8 bytes */ |
| size = round_up(size, 8); |
| |
| 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); |
| } |
| } |
| |
| if (!onallcpus) { |
| /* copy true value_size bytes */ |
| memcpy(this_cpu_ptr(pptr), value, htab->map.value_size); |
| } else { |
| int off = 0, cpu; |
| |
| for_each_possible_cpu(cpu) { |
| bpf_long_memcpy(per_cpu_ptr(pptr, cpu), |
| value + off, size); |
| off += size; |
| } |
| } |
| 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_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_add_head_rcu(&l_new->hash_node, head); |
| if (l_old) { |
| hlist_del_rcu(&l_old->hash_node); |
| free_htab_elem(htab, l_old); |
| } |
| ret = 0; |
| err: |
| raw_spin_unlock_irqrestore(&b->lock, flags); |
| 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_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) { |
| void __percpu *pptr = htab_elem_get_ptr(l_old, key_size); |
| u32 size = htab->map.value_size; |
| |
| /* per-cpu hash map can update value in-place */ |
| if (!onallcpus) { |
| memcpy(this_cpu_ptr(pptr), value, size); |
| } else { |
| int off = 0, cpu; |
| |
| size = round_up(size, 8); |
| for_each_possible_cpu(cpu) { |
| bpf_long_memcpy(per_cpu_ptr(pptr, cpu), |
| value + off, size); |
| off += size; |
| } |
| } |
| } else { |
| l_new = alloc_htab_elem(htab, key, value, key_size, |
| hash, true, onallcpus, false); |
| if (IS_ERR(l_new)) { |
| ret = PTR_ERR(l_new); |
| goto err; |
| } |
| hlist_add_head_rcu(&l_new->hash_node, head); |
| } |
| ret = 0; |
| err: |
| raw_spin_unlock_irqrestore(&b->lock, flags); |
| return ret; |
| } |
| |
| static int 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); |
| } |
| |
| /* Called from syscall or from eBPF program */ |
| static int htab_map_delete_elem(struct bpf_map *map, void *key) |
| { |
| struct bpf_htab *htab = container_of(map, struct bpf_htab, map); |
| struct hlist_head *head; |
| struct bucket *b; |
| struct htab_elem *l; |
| unsigned long flags; |
| u32 hash, key_size; |
| int ret = -ENOENT; |
| |
| 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; |
| |
| raw_spin_lock_irqsave(&b->lock, flags); |
| |
| l = lookup_elem_raw(head, hash, key, key_size); |
| |
| if (l) { |
| hlist_del_rcu(&l->hash_node); |
| free_htab_elem(htab, l); |
| ret = 0; |
| } |
| |
| raw_spin_unlock_irqrestore(&b->lock, flags); |
| return ret; |
| } |
| |
| static void delete_all_elements(struct bpf_htab *htab) |
| { |
| int i; |
| |
| for (i = 0; i < htab->n_buckets; i++) { |
| struct hlist_head *head = select_bucket(htab, i); |
| struct hlist_node *n; |
| struct htab_elem *l; |
| |
| hlist_for_each_entry_safe(l, n, head, hash_node) { |
| hlist_del_rcu(&l->hash_node); |
| if (l->state != HTAB_EXTRA_ELEM_USED) |
| htab_elem_free(htab, l); |
| } |
| } |
| } |
| /* 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); |
| |
| /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, |
| * so the programs (can be more than one that used this map) were |
| * disconnected from events. Wait for outstanding critical sections in |
| * these programs to complete |
| */ |
| synchronize_rcu(); |
| |
| /* some of free_htab_elem() callbacks for elements of this map may |
| * not have executed. Wait for them. |
| */ |
| rcu_barrier(); |
| if (htab->map.map_flags & BPF_F_NO_PREALLOC) { |
| delete_all_elements(htab); |
| } else { |
| htab_free_elems(htab); |
| pcpu_freelist_destroy(&htab->freelist); |
| } |
| free_percpu(htab->extra_elems); |
| bpf_map_area_free(htab->buckets); |
| kfree(htab); |
| } |
| |
| static const struct bpf_map_ops htab_ops = { |
| .map_alloc = htab_map_alloc, |
| .map_free = htab_map_free, |
| .map_get_next_key = htab_map_get_next_key, |
| .map_lookup_elem = htab_map_lookup_elem, |
| .map_update_elem = htab_map_update_elem, |
| .map_delete_elem = htab_map_delete_elem, |
| }; |
| |
| static struct bpf_map_type_list htab_type __read_mostly = { |
| .ops = &htab_ops, |
| .type = BPF_MAP_TYPE_HASH, |
| }; |
| |
| /* 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; |
| } |
| |
| 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; |
| pptr = htab_elem_get_ptr(l, map->key_size); |
| for_each_possible_cpu(cpu) { |
| bpf_long_memcpy(value + off, |
| per_cpu_ptr(pptr, cpu), size); |
| 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) |
| { |
| int ret; |
| |
| rcu_read_lock(); |
| ret = __htab_percpu_map_update_elem(map, key, value, map_flags, true); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static const struct bpf_map_ops htab_percpu_ops = { |
| .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_update_elem = htab_percpu_map_update_elem, |
| .map_delete_elem = htab_map_delete_elem, |
| }; |
| |
| static struct bpf_map_type_list htab_percpu_type __read_mostly = { |
| .ops = &htab_percpu_ops, |
| .type = BPF_MAP_TYPE_PERCPU_HASH, |
| }; |
| |
| static int __init register_htab_map(void) |
| { |
| bpf_register_map_type(&htab_type); |
| bpf_register_map_type(&htab_percpu_type); |
| return 0; |
| } |
| late_initcall(register_htab_map); |