#include <linux/bpf.h>
#include <linux/jhash.h>
#include <linux/filter.h>
-#include <linux/vmalloc.h>
#include "percpu_freelist.h"
+#include "bpf_lru_list.h"
struct bucket {
struct hlist_head head;
struct bpf_map map;
struct bucket *buckets;
void *elems;
- struct pcpu_freelist freelist;
+ union {
+ struct pcpu_freelist freelist;
+ struct bpf_lru lru;
+ };
void __percpu *extra_elems;
atomic_t count; /* number of elements in this hashtable */
u32 n_buckets; /* number of hash buckets */
union {
struct rcu_head rcu;
enum extra_elem_state state;
+ 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 inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
void __percpu *pptr)
{
{
int i;
- if (htab->map.map_type != BPF_MAP_TYPE_PERCPU_HASH)
+ if (!htab_is_percpu(htab))
goto free_elems;
for (i = 0; i < htab->map.max_entries; i++) {
free_percpu(pptr);
}
free_elems:
- vfree(htab->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_elems_and_freelist(struct bpf_htab *htab)
+static int prealloc_init(struct bpf_htab *htab)
{
int err = -ENOMEM, i;
- htab->elems = vzalloc(htab->elem_size * htab->map.max_entries);
+ 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)
+ if (!htab_is_percpu(htab))
goto skip_percpu_elems;
for (i = 0; i < htab->map.max_entries; i++) {
}
skip_percpu_elems:
- err = pcpu_freelist_init(&htab->freelist);
+ 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;
- pcpu_freelist_populate(&htab->freelist, htab->elems, htab->elem_size,
- htab->map.max_entries);
+ if (htab_is_lru(htab))
+ bpf_lru_populate(&htab->lru, htab->elems,
+ offsetof(struct htab_elem, lru_node),
+ htab->elem_size, htab->map.max_entries);
+ else
+ pcpu_freelist_populate(&htab->freelist, htab->elems,
+ htab->elem_size, htab->map.max_entries);
+
return 0;
free_elems:
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)
{
void __percpu *pptr;
/* Called from syscall */
static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
{
- bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_HASH;
+ 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;
u64 cost;
- if (attr->map_flags & ~BPF_F_NO_PREALLOC)
+ 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 & ~(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU))
/* 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);
+
htab = kzalloc(sizeof(*htab), GFP_USER);
if (!htab)
return ERR_PTR(-ENOMEM);
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);
*/
goto free_htab;
- if (htab->map.value_size >= (1 << (KMALLOC_SHIFT_MAX - 1)) -
+ 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
goto free_htab;
err = -ENOMEM;
- 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 bucket));
- if (!htab->buckets)
- goto free_htab;
- }
+ 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) {
+ 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_buckets;
}
- if (!(attr->map_flags & BPF_F_NO_PREALLOC)) {
- err = prealloc_elems_and_freelist(htab);
+ if (prealloc) {
+ err = prealloc_init(htab);
if (err)
goto free_extra_elems;
}
free_extra_elems:
free_percpu(htab->extra_elems);
free_buckets:
- kvfree(htab->buckets);
+ bpf_map_area_free(htab->buckets);
free_htab:
kfree(htab);
return ERR_PTR(err);
return NULL;
}
+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;
+}
+
+/* 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, *tgt_l;
+ struct hlist_head *head;
+ 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_for_each_entry_rcu(l, head, hash_node)
+ if (l == tgt_l) {
+ hlist_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)
{
}
}
+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 struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
void *value, u32 key_size, u32 hash,
bool percpu, bool onallcpus,
}
}
- if (!onallcpus) {
- /* copy true value_size bytes */
- memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
- } else {
- int off = 0, cpu;
+ pcpu_copy_value(htab, pptr, value, onallcpus);
- 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 {
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_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_add_head_rcu(&l_new->hash_node, head);
+ if (l_old) {
+ bpf_lru_node_set_ref(&l_new->lru_node);
+ hlist_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)
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;
- }
- }
+ 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, false);
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_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);
+
+ 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_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
+ value, onallcpus);
+ hlist_add_head_rcu(&l_new->hash_node, head);
+ l_new = NULL;
+ }
+ ret = 0;
+err:
+ raw_spin_unlock_irqrestore(&b->lock, flags);
+ if (l_new)
+ bpf_lru_push_free(&htab->lru, &l_new->lru_node);
+ 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);
}
+static int 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 int htab_map_delete_elem(struct bpf_map *map, void *key)
{
return ret;
}
+static int htab_lru_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);
+ ret = 0;
+ }
+
+ raw_spin_unlock_irqrestore(&b->lock, flags);
+ if (l)
+ bpf_lru_push_free(&htab->lru, &l->lru_node);
+ return ret;
+}
+
static void delete_all_elements(struct bpf_htab *htab)
{
int i;
* not have executed. Wait for them.
*/
rcu_barrier();
- if (htab->map.map_flags & BPF_F_NO_PREALLOC) {
+ if (htab->map.map_flags & BPF_F_NO_PREALLOC)
delete_all_elements(htab);
- } else {
- htab_free_elems(htab);
- pcpu_freelist_destroy(&htab->freelist);
- }
+ else
+ prealloc_destroy(htab);
+
free_percpu(htab->extra_elems);
- kvfree(htab->buckets);
+ bpf_map_area_free(htab->buckets);
kfree(htab);
}
.type = BPF_MAP_TYPE_HASH,
};
+static const struct bpf_map_ops htab_lru_ops = {
+ .map_alloc = htab_map_alloc,
+ .map_free = htab_map_free,
+ .map_get_next_key = htab_map_get_next_key,
+ .map_lookup_elem = htab_lru_map_lookup_elem,
+ .map_update_elem = htab_lru_map_update_elem,
+ .map_delete_elem = htab_lru_map_delete_elem,
+};
+
+static struct bpf_map_type_list htab_lru_type __read_mostly = {
+ .ops = &htab_lru_ops,
+ .type = BPF_MAP_TYPE_LRU_HASH,
+};
+
/* Called from eBPF program */
static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
{
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;
+}
+
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
{
+ struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l;
void __percpu *pptr;
int ret = -ENOENT;
l = __htab_map_lookup_elem(map, key);
if (!l)
goto out;
+ if (htab_is_lru(htab))
+ bpf_lru_node_set_ref(&l->lru_node);
pptr = htab_elem_get_ptr(l, map->key_size);
for_each_possible_cpu(cpu) {
bpf_long_memcpy(value + off,
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();
- ret = __htab_percpu_map_update_elem(map, key, value, map_flags, true);
+ 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;
.type = BPF_MAP_TYPE_PERCPU_HASH,
};
+static const struct bpf_map_ops htab_lru_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_lru_percpu_map_lookup_elem,
+ .map_update_elem = htab_lru_percpu_map_update_elem,
+ .map_delete_elem = htab_lru_map_delete_elem,
+};
+
+static struct bpf_map_type_list htab_lru_percpu_type __read_mostly = {
+ .ops = &htab_lru_percpu_ops,
+ .type = BPF_MAP_TYPE_LRU_PERCPU_HASH,
+};
+
static int __init register_htab_map(void)
{
bpf_register_map_type(&htab_type);
bpf_register_map_type(&htab_percpu_type);
+ bpf_register_map_type(&htab_lru_type);
+ bpf_register_map_type(&htab_lru_percpu_type);
return 0;
}
late_initcall(register_htab_map);
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