1 files changed, 150 insertions, 35 deletions

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 361a69dfe543..004334ea13ba 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -16,6 +16,7 @@
 #include <linux/rculist_nulls.h>
 #include "percpu_freelist.h"
 #include "bpf_lru_list.h"
+#include "map_in_map.h"
 
 struct bucket {
 	struct hlist_nulls_head head;
@@ -86,6 +87,11 @@ 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);
@@ -426,7 +432,11 @@ again:
 	return NULL;
 }
 
-/* Called from syscall or from eBPF program */
+/* 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);
@@ -458,6 +468,30 @@ static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
 	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);
@@ -506,12 +540,15 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 	struct hlist_nulls_head *head;
 	struct htab_elem *l, *next_l;
 	u32 hash, key_size;
-	int i;
+	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);
@@ -519,10 +556,8 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 	/* lookup the key */
 	l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets);
 
-	if (!l) {
-		i = 0;
+	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)),
@@ -582,6 +617,14 @@ static void htab_elem_free_rcu(struct rcu_head *head)
 
 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 {
@@ -1027,6 +1070,7 @@ static void delete_all_elements(struct bpf_htab *htab)
 		}
 	}
 }
+
 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
 static void htab_map_free(struct bpf_map *map)
 {
@@ -1053,21 +1097,17 @@ static void htab_map_free(struct bpf_map *map)
 	kfree(htab);
 }
 
-static const struct bpf_map_ops htab_ops = {
+const struct bpf_map_ops htab_map_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,
+	.map_gen_lookup = htab_map_gen_lookup,
 };
 
-static struct bpf_map_type_list htab_type __ro_after_init = {
-	.ops = &htab_ops,
-	.type = BPF_MAP_TYPE_HASH,
-};
-
-static const struct bpf_map_ops htab_lru_ops = {
+const struct bpf_map_ops htab_lru_map_ops = {
 	.map_alloc = htab_map_alloc,
 	.map_free = htab_map_free,
 	.map_get_next_key = htab_map_get_next_key,
@@ -1076,11 +1116,6 @@ static const struct bpf_map_ops htab_lru_ops = {
 	.map_delete_elem = htab_lru_map_delete_elem,
 };
 
-static struct bpf_map_type_list htab_lru_type __ro_after_init = {
-	.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)
 {
@@ -1154,7 +1189,7 @@ int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
 	return ret;
 }
 
-static const struct bpf_map_ops htab_percpu_ops = {
+const struct bpf_map_ops htab_percpu_map_ops = {
 	.map_alloc = htab_map_alloc,
 	.map_free = htab_map_free,
 	.map_get_next_key = htab_map_get_next_key,
@@ -1163,12 +1198,7 @@ static const struct bpf_map_ops htab_percpu_ops = {
 	.map_delete_elem = htab_map_delete_elem,
 };
 
-static struct bpf_map_type_list htab_percpu_type __ro_after_init = {
-	.ops = &htab_percpu_ops,
-	.type = BPF_MAP_TYPE_PERCPU_HASH,
-};
-
-static const struct bpf_map_ops htab_lru_percpu_ops = {
+const struct bpf_map_ops htab_lru_percpu_map_ops = {
 	.map_alloc = htab_map_alloc,
 	.map_free = htab_map_free,
 	.map_get_next_key = htab_map_get_next_key,
@@ -1177,17 +1207,102 @@ static const struct bpf_map_ops htab_lru_percpu_ops = {
 	.map_delete_elem = htab_lru_map_delete_elem,
 };
 
-static struct bpf_map_type_list htab_lru_percpu_type __ro_after_init = {
-	.ops = &htab_lru_percpu_ops,
-	.type = BPF_MAP_TYPE_LRU_PERCPU_HASH,
-};
+static struct bpf_map *fd_htab_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_map *map;
+
+	if (attr->value_size != sizeof(u32))
+		return ERR_PTR(-EINVAL);
+
+	/* pointer is stored internally */
+	attr->value_size = sizeof(void *);
+	map = htab_map_alloc(attr);
+	attr->value_size = sizeof(u32);
 
-static int __init register_htab_map(void)
+	return map;
+}
+
+static void fd_htab_map_free(struct bpf_map *map)
 {
-	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;
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+	struct hlist_nulls_node *n;
+	struct hlist_nulls_head *head;
+	struct htab_elem *l;
+	int i;
+
+	for (i = 0; i < htab->n_buckets; i++) {
+		head = select_bucket(htab, i);
+
+		hlist_nulls_for_each_entry_safe(l, n, head, hash_node) {
+			void *ptr = fd_htab_map_get_ptr(map, l);
+
+			map->ops->map_fd_put_ptr(ptr);
+		}
+	}
+
+	htab_map_free(map);
+}
+
+/* only called from syscall */
+int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
+				void *key, void *value, u64 map_flags)
+{
+	void *ptr;
+	int ret;
+	u32 ufd = *(u32 *)value;
+
+	ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	ret = htab_map_update_elem(map, key, &ptr, map_flags);
+	if (ret)
+		map->ops->map_fd_put_ptr(ptr);
+
+	return ret;
+}
+
+static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_map *map, *inner_map_meta;
+
+	inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
+	if (IS_ERR(inner_map_meta))
+		return inner_map_meta;
+
+	map = fd_htab_map_alloc(attr);
+	if (IS_ERR(map)) {
+		bpf_map_meta_free(inner_map_meta);
+		return map;
+	}
+
+	map->inner_map_meta = inner_map_meta;
+
+	return map;
 }
-late_initcall(register_htab_map);
+
+static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_map **inner_map  = htab_map_lookup_elem(map, key);
+
+	if (!inner_map)
+		return NULL;
+
+	return READ_ONCE(*inner_map);
+}
+
+static void htab_of_map_free(struct bpf_map *map)
+{
+	bpf_map_meta_free(map->inner_map_meta);
+	fd_htab_map_free(map);
+}
+
+const struct bpf_map_ops htab_of_maps_map_ops = {
+	.map_alloc = htab_of_map_alloc,
+	.map_free = htab_of_map_free,
+	.map_get_next_key = htab_map_get_next_key,
+	.map_lookup_elem = htab_of_map_lookup_elem,
+	.map_delete_elem = htab_map_delete_elem,
+	.map_fd_get_ptr = bpf_map_fd_get_ptr,
+	.map_fd_put_ptr = bpf_map_fd_put_ptr,
+};