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author | David S. Miller <davem@davemloft.net> | 2016-01-13 06:21:27 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2016-01-13 06:21:27 +0100 |
commit | ddb5388ffd0ad75d07e7b78181a0b579824ba6f0 (patch) | |
tree | be1e2bd103c69d7bbace3fffd97bc3d714bbc3d7 /kernel/bpf/hashtab.c | |
parent | net: netlink: Fix multicast group storage allocation for families with more t... (diff) | |
parent | Merge tag 'pm+acpi-4.5-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/gi... (diff) | |
download | linux-ddb5388ffd0ad75d07e7b78181a0b579824ba6f0.tar.xz linux-ddb5388ffd0ad75d07e7b78181a0b579824ba6f0.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux
Diffstat (limited to 'kernel/bpf/hashtab.c')
-rw-r--r-- | kernel/bpf/hashtab.c | 64 |
1 files changed, 38 insertions, 26 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 34777b3746fa..c5b30fd8a315 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -14,11 +14,15 @@ #include <linux/filter.h> #include <linux/vmalloc.h> +struct bucket { + struct hlist_head head; + raw_spinlock_t lock; +}; + struct bpf_htab { struct bpf_map map; - struct hlist_head *buckets; - raw_spinlock_t lock; - u32 count; /* number of elements in this hashtable */ + struct bucket *buckets; + 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 */ }; @@ -79,34 +83,35 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) /* prevent zero size kmalloc and check for u32 overflow */ if (htab->n_buckets == 0 || - htab->n_buckets > U32_MAX / sizeof(struct hlist_head)) + htab->n_buckets > U32_MAX / sizeof(struct bucket)) goto free_htab; - if ((u64) htab->n_buckets * sizeof(struct hlist_head) + + if ((u64) htab->n_buckets * sizeof(struct bucket) + (u64) htab->elem_size * htab->map.max_entries >= U32_MAX - PAGE_SIZE) /* make sure page count doesn't overflow */ goto free_htab; - htab->map.pages = round_up(htab->n_buckets * sizeof(struct hlist_head) + + htab->map.pages = round_up(htab->n_buckets * sizeof(struct bucket) + htab->elem_size * htab->map.max_entries, PAGE_SIZE) >> PAGE_SHIFT; err = -ENOMEM; - htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct hlist_head), + htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct bucket), GFP_USER | __GFP_NOWARN); if (!htab->buckets) { - htab->buckets = vmalloc(htab->n_buckets * sizeof(struct hlist_head)); + htab->buckets = vmalloc(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]); + for (i = 0; i < htab->n_buckets; i++) { + INIT_HLIST_HEAD(&htab->buckets[i].head); + raw_spin_lock_init(&htab->buckets[i].lock); + } - raw_spin_lock_init(&htab->lock); - htab->count = 0; + atomic_set(&htab->count, 0); return &htab->map; @@ -120,11 +125,16 @@ static inline u32 htab_map_hash(const void *key, u32 key_len) return jhash(key, key_len, 0); } -static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash) +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) { @@ -227,6 +237,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, struct bpf_htab *htab = container_of(map, struct bpf_htab, map); struct htab_elem *l_new, *l_old; struct hlist_head *head; + struct bucket *b; unsigned long flags; u32 key_size; int ret; @@ -248,15 +259,15 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, memcpy(l_new->key + round_up(key_size, 8), value, map->value_size); l_new->hash = htab_map_hash(l_new->key, key_size); + b = __select_bucket(htab, l_new->hash); + head = &b->head; /* bpf_map_update_elem() can be called in_irq() */ - raw_spin_lock_irqsave(&htab->lock, flags); - - head = select_bucket(htab, l_new->hash); + raw_spin_lock_irqsave(&b->lock, flags); l_old = lookup_elem_raw(head, l_new->hash, key, key_size); - if (!l_old && unlikely(htab->count >= map->max_entries)) { + if (!l_old && unlikely(atomic_read(&htab->count) >= map->max_entries)) { /* if elem with this 'key' doesn't exist and we've reached * max_entries limit, fail insertion of new elem */ @@ -284,13 +295,13 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, hlist_del_rcu(&l_old->hash_node); kfree_rcu(l_old, rcu); } else { - htab->count++; + atomic_inc(&htab->count); } - raw_spin_unlock_irqrestore(&htab->lock, flags); + raw_spin_unlock_irqrestore(&b->lock, flags); return 0; err: - raw_spin_unlock_irqrestore(&htab->lock, flags); + raw_spin_unlock_irqrestore(&b->lock, flags); kfree(l_new); return ret; } @@ -300,6 +311,7 @@ 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; @@ -310,21 +322,21 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key) key_size = map->key_size; hash = htab_map_hash(key, key_size); + b = __select_bucket(htab, hash); + head = &b->head; - raw_spin_lock_irqsave(&htab->lock, flags); - - head = select_bucket(htab, hash); + raw_spin_lock_irqsave(&b->lock, flags); l = lookup_elem_raw(head, hash, key, key_size); if (l) { hlist_del_rcu(&l->hash_node); - htab->count--; + atomic_dec(&htab->count); kfree_rcu(l, rcu); ret = 0; } - raw_spin_unlock_irqrestore(&htab->lock, flags); + raw_spin_unlock_irqrestore(&b->lock, flags); return ret; } @@ -339,7 +351,7 @@ static void delete_all_elements(struct bpf_htab *htab) hlist_for_each_entry_safe(l, n, head, hash_node) { hlist_del_rcu(&l->hash_node); - htab->count--; + atomic_dec(&htab->count); kfree(l); } } |