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608 lines
14 KiB
608 lines
14 KiB
//SPDX-License-Identifier: GPL-2.0 |
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#include <linux/bpf-cgroup.h> |
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#include <linux/bpf.h> |
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#include <linux/bpf_local_storage.h> |
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#include <linux/btf.h> |
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#include <linux/bug.h> |
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#include <linux/filter.h> |
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#include <linux/mm.h> |
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#include <linux/rbtree.h> |
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#include <linux/slab.h> |
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#include <uapi/linux/btf.h> |
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|
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#ifdef CONFIG_CGROUP_BPF |
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|
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#include "../cgroup/cgroup-internal.h" |
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|
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#define LOCAL_STORAGE_CREATE_FLAG_MASK \ |
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(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK) |
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struct bpf_cgroup_storage_map { |
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struct bpf_map map; |
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spinlock_t lock; |
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struct rb_root root; |
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struct list_head list; |
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}; |
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static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map) |
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{ |
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return container_of(map, struct bpf_cgroup_storage_map, map); |
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} |
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static bool attach_type_isolated(const struct bpf_map *map) |
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{ |
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return map->key_size == sizeof(struct bpf_cgroup_storage_key); |
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} |
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static int bpf_cgroup_storage_key_cmp(const struct bpf_cgroup_storage_map *map, |
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const void *_key1, const void *_key2) |
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{ |
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if (attach_type_isolated(&map->map)) { |
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const struct bpf_cgroup_storage_key *key1 = _key1; |
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const struct bpf_cgroup_storage_key *key2 = _key2; |
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if (key1->cgroup_inode_id < key2->cgroup_inode_id) |
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return -1; |
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else if (key1->cgroup_inode_id > key2->cgroup_inode_id) |
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return 1; |
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else if (key1->attach_type < key2->attach_type) |
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return -1; |
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else if (key1->attach_type > key2->attach_type) |
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return 1; |
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} else { |
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const __u64 *cgroup_inode_id1 = _key1; |
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const __u64 *cgroup_inode_id2 = _key2; |
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if (*cgroup_inode_id1 < *cgroup_inode_id2) |
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return -1; |
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else if (*cgroup_inode_id1 > *cgroup_inode_id2) |
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return 1; |
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} |
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return 0; |
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} |
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struct bpf_cgroup_storage * |
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cgroup_storage_lookup(struct bpf_cgroup_storage_map *map, |
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void *key, bool locked) |
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{ |
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struct rb_root *root = &map->root; |
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struct rb_node *node; |
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if (!locked) |
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spin_lock_bh(&map->lock); |
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node = root->rb_node; |
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while (node) { |
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struct bpf_cgroup_storage *storage; |
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storage = container_of(node, struct bpf_cgroup_storage, node); |
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switch (bpf_cgroup_storage_key_cmp(map, key, &storage->key)) { |
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case -1: |
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node = node->rb_left; |
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break; |
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case 1: |
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node = node->rb_right; |
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break; |
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default: |
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if (!locked) |
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spin_unlock_bh(&map->lock); |
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return storage; |
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} |
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} |
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if (!locked) |
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spin_unlock_bh(&map->lock); |
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return NULL; |
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} |
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static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map, |
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struct bpf_cgroup_storage *storage) |
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{ |
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struct rb_root *root = &map->root; |
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struct rb_node **new = &(root->rb_node), *parent = NULL; |
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while (*new) { |
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struct bpf_cgroup_storage *this; |
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this = container_of(*new, struct bpf_cgroup_storage, node); |
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parent = *new; |
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switch (bpf_cgroup_storage_key_cmp(map, &storage->key, &this->key)) { |
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case -1: |
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new = &((*new)->rb_left); |
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break; |
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case 1: |
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new = &((*new)->rb_right); |
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break; |
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default: |
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return -EEXIST; |
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} |
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} |
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rb_link_node(&storage->node, parent, new); |
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rb_insert_color(&storage->node, root); |
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return 0; |
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} |
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static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *key) |
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{ |
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struct bpf_cgroup_storage_map *map = map_to_storage(_map); |
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struct bpf_cgroup_storage *storage; |
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storage = cgroup_storage_lookup(map, key, false); |
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if (!storage) |
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return NULL; |
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return &READ_ONCE(storage->buf)->data[0]; |
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} |
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static int cgroup_storage_update_elem(struct bpf_map *map, void *key, |
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void *value, u64 flags) |
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{ |
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struct bpf_cgroup_storage *storage; |
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struct bpf_storage_buffer *new; |
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if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST))) |
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return -EINVAL; |
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if (unlikely((flags & BPF_F_LOCK) && |
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!map_value_has_spin_lock(map))) |
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return -EINVAL; |
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storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map, |
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key, false); |
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if (!storage) |
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return -ENOENT; |
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if (flags & BPF_F_LOCK) { |
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copy_map_value_locked(map, storage->buf->data, value, false); |
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return 0; |
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} |
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new = bpf_map_kmalloc_node(map, sizeof(struct bpf_storage_buffer) + |
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map->value_size, |
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__GFP_ZERO | GFP_ATOMIC | __GFP_NOWARN, |
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map->numa_node); |
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if (!new) |
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return -ENOMEM; |
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memcpy(&new->data[0], value, map->value_size); |
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check_and_init_map_value(map, new->data); |
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new = xchg(&storage->buf, new); |
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kfree_rcu(new, rcu); |
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return 0; |
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} |
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int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, |
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void *value) |
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{ |
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struct bpf_cgroup_storage_map *map = map_to_storage(_map); |
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struct bpf_cgroup_storage *storage; |
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int cpu, off = 0; |
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u32 size; |
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rcu_read_lock(); |
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storage = cgroup_storage_lookup(map, key, false); |
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if (!storage) { |
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rcu_read_unlock(); |
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return -ENOENT; |
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} |
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/* per_cpu areas are zero-filled and bpf programs can only |
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* access 'value_size' of them, so copying rounded areas |
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* will not leak any kernel data |
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*/ |
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size = round_up(_map->value_size, 8); |
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for_each_possible_cpu(cpu) { |
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bpf_long_memcpy(value + off, |
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per_cpu_ptr(storage->percpu_buf, cpu), size); |
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off += size; |
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} |
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rcu_read_unlock(); |
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return 0; |
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} |
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int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, |
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void *value, u64 map_flags) |
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{ |
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struct bpf_cgroup_storage_map *map = map_to_storage(_map); |
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struct bpf_cgroup_storage *storage; |
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int cpu, off = 0; |
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u32 size; |
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if (map_flags != BPF_ANY && map_flags != BPF_EXIST) |
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return -EINVAL; |
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rcu_read_lock(); |
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storage = cgroup_storage_lookup(map, key, false); |
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if (!storage) { |
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rcu_read_unlock(); |
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return -ENOENT; |
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} |
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/* the user space will provide round_up(value_size, 8) bytes that |
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* will be copied into per-cpu area. bpf programs can only access |
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* value_size of it. During lookup the same extra bytes will be |
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* returned or zeros which were zero-filled by percpu_alloc, |
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* so no kernel data leaks possible |
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*/ |
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size = round_up(_map->value_size, 8); |
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for_each_possible_cpu(cpu) { |
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bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu), |
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value + off, size); |
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off += size; |
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} |
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rcu_read_unlock(); |
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return 0; |
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} |
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static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key, |
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void *_next_key) |
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{ |
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struct bpf_cgroup_storage_map *map = map_to_storage(_map); |
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struct bpf_cgroup_storage *storage; |
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spin_lock_bh(&map->lock); |
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if (list_empty(&map->list)) |
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goto enoent; |
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if (key) { |
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storage = cgroup_storage_lookup(map, key, true); |
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if (!storage) |
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goto enoent; |
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storage = list_next_entry(storage, list_map); |
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if (!storage) |
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goto enoent; |
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} else { |
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storage = list_first_entry(&map->list, |
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struct bpf_cgroup_storage, list_map); |
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} |
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spin_unlock_bh(&map->lock); |
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if (attach_type_isolated(&map->map)) { |
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struct bpf_cgroup_storage_key *next = _next_key; |
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*next = storage->key; |
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} else { |
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__u64 *next = _next_key; |
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*next = storage->key.cgroup_inode_id; |
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} |
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return 0; |
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enoent: |
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spin_unlock_bh(&map->lock); |
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return -ENOENT; |
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} |
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static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr) |
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{ |
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__u32 max_value_size = BPF_LOCAL_STORAGE_MAX_VALUE_SIZE; |
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int numa_node = bpf_map_attr_numa_node(attr); |
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struct bpf_cgroup_storage_map *map; |
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/* percpu is bound by PCPU_MIN_UNIT_SIZE, non-percu |
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* is the same as other local storages. |
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*/ |
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if (attr->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) |
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max_value_size = min_t(__u32, max_value_size, |
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PCPU_MIN_UNIT_SIZE); |
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if (attr->key_size != sizeof(struct bpf_cgroup_storage_key) && |
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attr->key_size != sizeof(__u64)) |
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return ERR_PTR(-EINVAL); |
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if (attr->value_size == 0) |
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return ERR_PTR(-EINVAL); |
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if (attr->value_size > max_value_size) |
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return ERR_PTR(-E2BIG); |
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if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK || |
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!bpf_map_flags_access_ok(attr->map_flags)) |
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return ERR_PTR(-EINVAL); |
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if (attr->max_entries) |
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/* max_entries is not used and enforced to be 0 */ |
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return ERR_PTR(-EINVAL); |
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map = kmalloc_node(sizeof(struct bpf_cgroup_storage_map), |
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__GFP_ZERO | GFP_USER | __GFP_ACCOUNT, numa_node); |
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if (!map) |
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return ERR_PTR(-ENOMEM); |
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/* copy mandatory map attributes */ |
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bpf_map_init_from_attr(&map->map, attr); |
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spin_lock_init(&map->lock); |
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map->root = RB_ROOT; |
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INIT_LIST_HEAD(&map->list); |
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return &map->map; |
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} |
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static void cgroup_storage_map_free(struct bpf_map *_map) |
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{ |
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struct bpf_cgroup_storage_map *map = map_to_storage(_map); |
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struct list_head *storages = &map->list; |
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struct bpf_cgroup_storage *storage, *stmp; |
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mutex_lock(&cgroup_mutex); |
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list_for_each_entry_safe(storage, stmp, storages, list_map) { |
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bpf_cgroup_storage_unlink(storage); |
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bpf_cgroup_storage_free(storage); |
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} |
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mutex_unlock(&cgroup_mutex); |
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WARN_ON(!RB_EMPTY_ROOT(&map->root)); |
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WARN_ON(!list_empty(&map->list)); |
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kfree(map); |
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} |
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static int cgroup_storage_delete_elem(struct bpf_map *map, void *key) |
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{ |
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return -EINVAL; |
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} |
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static int cgroup_storage_check_btf(const struct bpf_map *map, |
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const struct btf *btf, |
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const struct btf_type *key_type, |
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const struct btf_type *value_type) |
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{ |
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if (attach_type_isolated(map)) { |
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struct btf_member *m; |
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u32 offset, size; |
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/* Key is expected to be of struct bpf_cgroup_storage_key type, |
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* which is: |
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* struct bpf_cgroup_storage_key { |
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* __u64 cgroup_inode_id; |
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* __u32 attach_type; |
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* }; |
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*/ |
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/* |
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* Key_type must be a structure with two fields. |
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*/ |
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if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT || |
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BTF_INFO_VLEN(key_type->info) != 2) |
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return -EINVAL; |
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/* |
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* The first field must be a 64 bit integer at 0 offset. |
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*/ |
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m = (struct btf_member *)(key_type + 1); |
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size = sizeof_field(struct bpf_cgroup_storage_key, cgroup_inode_id); |
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if (!btf_member_is_reg_int(btf, key_type, m, 0, size)) |
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return -EINVAL; |
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/* |
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* The second field must be a 32 bit integer at 64 bit offset. |
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*/ |
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m++; |
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offset = offsetof(struct bpf_cgroup_storage_key, attach_type); |
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size = sizeof_field(struct bpf_cgroup_storage_key, attach_type); |
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if (!btf_member_is_reg_int(btf, key_type, m, offset, size)) |
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return -EINVAL; |
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} else { |
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u32 int_data; |
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/* |
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* Key is expected to be u64, which stores the cgroup_inode_id |
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*/ |
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if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT) |
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return -EINVAL; |
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int_data = *(u32 *)(key_type + 1); |
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if (BTF_INT_BITS(int_data) != 64 || BTF_INT_OFFSET(int_data)) |
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return -EINVAL; |
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} |
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return 0; |
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} |
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static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *key, |
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struct seq_file *m) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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struct bpf_cgroup_storage *storage; |
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int cpu; |
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rcu_read_lock(); |
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storage = cgroup_storage_lookup(map_to_storage(map), key, false); |
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if (!storage) { |
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rcu_read_unlock(); |
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return; |
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} |
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btf_type_seq_show(map->btf, map->btf_key_type_id, key, m); |
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stype = cgroup_storage_type(map); |
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if (stype == BPF_CGROUP_STORAGE_SHARED) { |
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seq_puts(m, ": "); |
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btf_type_seq_show(map->btf, map->btf_value_type_id, |
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&READ_ONCE(storage->buf)->data[0], m); |
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seq_puts(m, "\n"); |
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} else { |
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seq_puts(m, ": {\n"); |
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for_each_possible_cpu(cpu) { |
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seq_printf(m, "\tcpu%d: ", cpu); |
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btf_type_seq_show(map->btf, map->btf_value_type_id, |
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per_cpu_ptr(storage->percpu_buf, cpu), |
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m); |
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seq_puts(m, "\n"); |
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} |
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seq_puts(m, "}\n"); |
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} |
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rcu_read_unlock(); |
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} |
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static int cgroup_storage_map_btf_id; |
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const struct bpf_map_ops cgroup_storage_map_ops = { |
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.map_alloc = cgroup_storage_map_alloc, |
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.map_free = cgroup_storage_map_free, |
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.map_get_next_key = cgroup_storage_get_next_key, |
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.map_lookup_elem = cgroup_storage_lookup_elem, |
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.map_update_elem = cgroup_storage_update_elem, |
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.map_delete_elem = cgroup_storage_delete_elem, |
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.map_check_btf = cgroup_storage_check_btf, |
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.map_seq_show_elem = cgroup_storage_seq_show_elem, |
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.map_btf_name = "bpf_cgroup_storage_map", |
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.map_btf_id = &cgroup_storage_map_btf_id, |
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}; |
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int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map) |
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{ |
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enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map); |
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if (aux->cgroup_storage[stype] && |
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aux->cgroup_storage[stype] != _map) |
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return -EBUSY; |
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aux->cgroup_storage[stype] = _map; |
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return 0; |
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} |
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static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages) |
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{ |
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size_t size; |
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if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) { |
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size = sizeof(struct bpf_storage_buffer) + map->value_size; |
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*pages = round_up(sizeof(struct bpf_cgroup_storage) + size, |
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PAGE_SIZE) >> PAGE_SHIFT; |
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} else { |
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size = map->value_size; |
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*pages = round_up(round_up(size, 8) * num_possible_cpus(), |
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PAGE_SIZE) >> PAGE_SHIFT; |
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} |
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return size; |
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} |
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struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog, |
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enum bpf_cgroup_storage_type stype) |
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{ |
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const gfp_t gfp = __GFP_ZERO | GFP_USER; |
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struct bpf_cgroup_storage *storage; |
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struct bpf_map *map; |
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size_t size; |
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u32 pages; |
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map = prog->aux->cgroup_storage[stype]; |
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if (!map) |
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return NULL; |
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size = bpf_cgroup_storage_calculate_size(map, &pages); |
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storage = bpf_map_kmalloc_node(map, sizeof(struct bpf_cgroup_storage), |
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gfp, map->numa_node); |
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if (!storage) |
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goto enomem; |
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if (stype == BPF_CGROUP_STORAGE_SHARED) { |
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storage->buf = bpf_map_kmalloc_node(map, size, gfp, |
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map->numa_node); |
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if (!storage->buf) |
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goto enomem; |
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check_and_init_map_value(map, storage->buf->data); |
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} else { |
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storage->percpu_buf = bpf_map_alloc_percpu(map, size, 8, gfp); |
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if (!storage->percpu_buf) |
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goto enomem; |
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} |
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storage->map = (struct bpf_cgroup_storage_map *)map; |
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return storage; |
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enomem: |
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kfree(storage); |
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return ERR_PTR(-ENOMEM); |
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} |
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|
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static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu) |
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{ |
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struct bpf_cgroup_storage *storage = |
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container_of(rcu, struct bpf_cgroup_storage, rcu); |
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|
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kfree(storage->buf); |
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kfree(storage); |
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} |
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|
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static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu) |
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{ |
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struct bpf_cgroup_storage *storage = |
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container_of(rcu, struct bpf_cgroup_storage, rcu); |
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|
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free_percpu(storage->percpu_buf); |
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kfree(storage); |
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} |
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|
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void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage) |
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{ |
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enum bpf_cgroup_storage_type stype; |
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struct bpf_map *map; |
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|
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if (!storage) |
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return; |
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map = &storage->map->map; |
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stype = cgroup_storage_type(map); |
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if (stype == BPF_CGROUP_STORAGE_SHARED) |
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call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu); |
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else |
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call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu); |
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} |
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|
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void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage, |
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struct cgroup *cgroup, |
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enum bpf_attach_type type) |
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{ |
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struct bpf_cgroup_storage_map *map; |
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if (!storage) |
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return; |
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storage->key.attach_type = type; |
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storage->key.cgroup_inode_id = cgroup_id(cgroup); |
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map = storage->map; |
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spin_lock_bh(&map->lock); |
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WARN_ON(cgroup_storage_insert(map, storage)); |
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list_add(&storage->list_map, &map->list); |
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list_add(&storage->list_cg, &cgroup->bpf.storages); |
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spin_unlock_bh(&map->lock); |
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} |
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void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage) |
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{ |
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struct bpf_cgroup_storage_map *map; |
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struct rb_root *root; |
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if (!storage) |
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return; |
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map = storage->map; |
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spin_lock_bh(&map->lock); |
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root = &map->root; |
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rb_erase(&storage->node, root); |
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list_del(&storage->list_map); |
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list_del(&storage->list_cg); |
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spin_unlock_bh(&map->lock); |
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} |
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#endif
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