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-rw-r--r--kernel/bpf/hashtab.c253
-rw-r--r--kernel/bpf/lpm_trie.c6
2 files changed, 152 insertions, 107 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 3ea87fb19a94..361a69dfe543 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -13,11 +13,12 @@
#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"
struct bucket {
- struct hlist_head head;
+ struct hlist_nulls_head head;
raw_spinlock_t lock;
};
@@ -29,28 +30,26 @@ struct bpf_htab {
struct pcpu_freelist freelist;
struct bpf_lru lru;
};
- void __percpu *extra_elems;
+ 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 */
};
-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;
+ struct hlist_nulls_node hash_node;
+ struct {
+ void *padding;
+ union {
+ struct bpf_htab *htab;
+ struct pcpu_freelist_node fnode;
+ };
+ };
};
union {
struct rcu_head rcu;
- enum extra_elem_state state;
struct bpf_lru_node lru_node;
};
u32 hash;
@@ -71,6 +70,11 @@ static bool htab_is_percpu(const struct bpf_htab *htab)
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)
{
@@ -122,17 +126,20 @@ static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
static int prealloc_init(struct bpf_htab *htab)
{
+ u32 num_entries = htab->map.max_entries;
int err = -ENOMEM, i;
- htab->elems = bpf_map_area_alloc(htab->elem_size *
- htab->map.max_entries);
+ 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);
if (!htab->elems)
return -ENOMEM;
if (!htab_is_percpu(htab))
goto skip_percpu_elems;
- for (i = 0; i < htab->map.max_entries; i++) {
+ for (i = 0; i < num_entries; i++) {
u32 size = round_up(htab->map.value_size, 8);
void __percpu *pptr;
@@ -160,10 +167,11 @@ skip_percpu_elems:
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);
+ htab->elem_size, num_entries);
else
- pcpu_freelist_populate(&htab->freelist, htab->elems,
- htab->elem_size, htab->map.max_entries);
+ pcpu_freelist_populate(&htab->freelist,
+ htab->elems + offsetof(struct htab_elem, fnode),
+ htab->elem_size, num_entries);
return 0;
@@ -184,16 +192,22 @@ static void prealloc_destroy(struct bpf_htab *htab)
static int alloc_extra_elems(struct bpf_htab *htab)
{
- void __percpu *pptr;
+ struct htab_elem *__percpu *pptr, *l_new;
+ struct pcpu_freelist_node *l;
int cpu;
- pptr = __alloc_percpu_gfp(htab->elem_size, 8, GFP_USER | __GFP_NOWARN);
+ pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 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;
+ 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;
@@ -217,6 +231,11 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
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.
@@ -326,29 +345,29 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
goto free_htab;
for (i = 0; i < htab->n_buckets; i++) {
- INIT_HLIST_HEAD(&htab->buckets[i].head);
+ INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
raw_spin_lock_init(&htab->buckets[i].lock);
}
- 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 (prealloc) {
err = prealloc_init(htab);
if (err)
- goto free_extra_elems;
+ 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_extra_elems:
- free_percpu(htab->extra_elems);
+free_prealloc:
+ prealloc_destroy(htab);
free_buckets:
bpf_map_area_free(htab->buckets);
free_htab:
@@ -366,20 +385,44 @@ 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)
+static inline struct hlist_nulls_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,
+/* 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;
- hlist_for_each_entry_rcu(l, head, hash_node)
+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;
}
@@ -387,7 +430,7 @@ static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,
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 hlist_nulls_head *head;
struct htab_elem *l;
u32 hash, key_size;
@@ -400,7 +443,7 @@ static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
head = select_bucket(htab, hash);
- l = lookup_elem_raw(head, hash, key, key_size);
+ l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
return l;
}
@@ -433,8 +476,9 @@ static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key)
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;
+ struct htab_elem *l = NULL, *tgt_l;
+ struct hlist_nulls_head *head;
+ struct hlist_nulls_node *n;
unsigned long flags;
struct bucket *b;
@@ -444,9 +488,9 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
raw_spin_lock_irqsave(&b->lock, flags);
- hlist_for_each_entry_rcu(l, head, hash_node)
+ hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
if (l == tgt_l) {
- hlist_del_rcu(&l->hash_node);
+ hlist_nulls_del_rcu(&l->hash_node);
break;
}
@@ -459,7 +503,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node)
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 hlist_nulls_head *head;
struct htab_elem *l, *next_l;
u32 hash, key_size;
int i;
@@ -473,7 +517,7 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
head = select_bucket(htab, hash);
/* lookup the key */
- l = lookup_elem_raw(head, hash, key, key_size);
+ l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
if (!l) {
i = 0;
@@ -481,7 +525,7 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
}
/* key was found, get next key in the same bucket */
- next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)),
+ next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_next_rcu(&l->hash_node)),
struct htab_elem, hash_node);
if (next_l) {
@@ -500,7 +544,7 @@ find_first_elem:
head = select_bucket(htab, i);
/* pick first element in the bucket */
- next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
+ 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 */
@@ -538,12 +582,7 @@ static void htab_elem_free_rcu(struct rcu_head *head)
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)) {
+ if (htab_is_prealloc(htab)) {
pcpu_freelist_push(&htab->freelist, &l->fnode);
} else {
atomic_dec(&htab->count);
@@ -573,43 +612,43 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
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)
+ struct htab_elem *old_elem)
{
u32 size = htab->map.value_size;
- bool prealloc = !(htab->map.map_flags & BPF_F_NO_PREALLOC);
- struct htab_elem *l_new;
+ bool prealloc = htab_is_prealloc(htab);
+ struct htab_elem *l_new, **pl_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;
+ 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 {
- l_new = kmalloc(htab->elem_size,
- GFP_ATOMIC | __GFP_NOWARN);
- if (!l_new)
- return ERR_PTR(-ENOMEM);
- }
- }
+ struct pcpu_freelist_node *l;
- 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;
+ l = pcpu_freelist_pop(&htab->freelist);
+ if (!l)
+ return ERR_PTR(-E2BIG);
+ l_new = container_of(l, struct htab_elem, fnode);
+ }
} else {
- l_new->state = HTAB_NOT_AN_EXTRA_ELEM;
+ 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(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN);
+ if (!l_new)
+ return ERR_PTR(-ENOMEM);
}
memcpy(l_new->key, key, key_size);
@@ -661,7 +700,7 @@ 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 = NULL, *l_old;
- struct hlist_head *head;
+ struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
@@ -690,7 +729,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
goto err;
l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
- !!l_old);
+ l_old);
if (IS_ERR(l_new)) {
/* all pre-allocated elements are in use or memory exhausted */
ret = PTR_ERR(l_new);
@@ -700,10 +739,11 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
/* 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);
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
if (l_old) {
- hlist_del_rcu(&l_old->hash_node);
- free_htab_elem(htab, l_old);
+ hlist_nulls_del_rcu(&l_old->hash_node);
+ if (!htab_is_prealloc(htab))
+ free_htab_elem(htab, l_old);
}
ret = 0;
err:
@@ -716,7 +756,7 @@ static int htab_lru_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 = NULL;
- struct hlist_head *head;
+ struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
@@ -757,10 +797,10 @@ static int htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value,
/* 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);
+ hlist_nulls_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);
+ hlist_nulls_del_rcu(&l_old->hash_node);
}
ret = 0;
@@ -781,7 +821,7 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new = NULL, *l_old;
- struct hlist_head *head;
+ struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
@@ -815,12 +855,12 @@ static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
value, onallcpus);
} else {
l_new = alloc_htab_elem(htab, key, value, key_size,
- hash, true, onallcpus, false);
+ hash, true, onallcpus, NULL);
if (IS_ERR(l_new)) {
ret = PTR_ERR(l_new);
goto err;
}
- hlist_add_head_rcu(&l_new->hash_node, head);
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
}
ret = 0;
err:
@@ -834,7 +874,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
{
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
struct htab_elem *l_new = NULL, *l_old;
- struct hlist_head *head;
+ struct hlist_nulls_head *head;
unsigned long flags;
struct bucket *b;
u32 key_size, hash;
@@ -882,7 +922,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
} else {
pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
value, onallcpus);
- hlist_add_head_rcu(&l_new->hash_node, head);
+ hlist_nulls_add_head_rcu(&l_new->hash_node, head);
l_new = NULL;
}
ret = 0;
@@ -910,7 +950,7 @@ static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
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 hlist_nulls_head *head;
struct bucket *b;
struct htab_elem *l;
unsigned long flags;
@@ -930,7 +970,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
l = lookup_elem_raw(head, hash, key, key_size);
if (l) {
- hlist_del_rcu(&l->hash_node);
+ hlist_nulls_del_rcu(&l->hash_node);
free_htab_elem(htab, l);
ret = 0;
}
@@ -942,7 +982,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key)
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 hlist_nulls_head *head;
struct bucket *b;
struct htab_elem *l;
unsigned long flags;
@@ -962,7 +1002,7 @@ static int htab_lru_map_delete_elem(struct bpf_map *map, void *key)
l = lookup_elem_raw(head, hash, key, key_size);
if (l) {
- hlist_del_rcu(&l->hash_node);
+ hlist_nulls_del_rcu(&l->hash_node);
ret = 0;
}
@@ -977,14 +1017,13 @@ 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 hlist_nulls_head *head = select_bucket(htab, i);
+ struct hlist_nulls_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);
+ hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+ hlist_nulls_del_rcu(&l->hash_node);
+ htab_elem_free(htab, l);
}
}
}
@@ -1004,7 +1043,7 @@ static void htab_map_free(struct bpf_map *map)
* not have executed. Wait for them.
*/
rcu_barrier();
- if (htab->map.map_flags & BPF_F_NO_PREALLOC)
+ if (!htab_is_prealloc(htab))
delete_all_elements(htab);
else
prealloc_destroy(htab);
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 8bfe0afaee10..b37bd9ab7f57 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -500,9 +500,15 @@ unlock:
raw_spin_unlock(&trie->lock);
}
+static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key)
+{
+ return -ENOTSUPP;
+}
+
static const struct bpf_map_ops trie_ops = {
.map_alloc = trie_alloc,
.map_free = trie_free,
+ .map_get_next_key = trie_get_next_key,
.map_lookup_elem = trie_lookup_elem,
.map_update_elem = trie_update_elem,
.map_delete_elem = trie_delete_elem,
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 01:29:20 +0000