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0dd668d208
In an effort to avoid open-coded arithmetic in the kernel, use the struct_size() helper instead of open-coded calculation. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://github.com/KSPP/linux/issues/160 Link: https://lore.kernel.org/bpf/20211220113048.2859-1-xiujianfeng@huawei.com
608 lines
14 KiB
C
608 lines
14 KiB
C
//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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#ifdef CONFIG_CGROUP_BPF
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#include "../cgroup/cgroup-internal.h"
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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, struct_size(new, data, 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;
|
|
|
|
map = prog->aux->cgroup_storage[stype];
|
|
if (!map)
|
|
return NULL;
|
|
|
|
size = bpf_cgroup_storage_calculate_size(map, &pages);
|
|
|
|
storage = bpf_map_kmalloc_node(map, sizeof(struct bpf_cgroup_storage),
|
|
gfp, map->numa_node);
|
|
if (!storage)
|
|
goto enomem;
|
|
|
|
if (stype == BPF_CGROUP_STORAGE_SHARED) {
|
|
storage->buf = bpf_map_kmalloc_node(map, size, gfp,
|
|
map->numa_node);
|
|
if (!storage->buf)
|
|
goto enomem;
|
|
check_and_init_map_value(map, storage->buf->data);
|
|
} else {
|
|
storage->percpu_buf = bpf_map_alloc_percpu(map, size, 8, gfp);
|
|
if (!storage->percpu_buf)
|
|
goto enomem;
|
|
}
|
|
|
|
storage->map = (struct bpf_cgroup_storage_map *)map;
|
|
|
|
return storage;
|
|
|
|
enomem:
|
|
kfree(storage);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
|
|
{
|
|
struct bpf_cgroup_storage *storage =
|
|
container_of(rcu, struct bpf_cgroup_storage, rcu);
|
|
|
|
kfree(storage->buf);
|
|
kfree(storage);
|
|
}
|
|
|
|
static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
|
|
{
|
|
struct bpf_cgroup_storage *storage =
|
|
container_of(rcu, struct bpf_cgroup_storage, rcu);
|
|
|
|
free_percpu(storage->percpu_buf);
|
|
kfree(storage);
|
|
}
|
|
|
|
void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
|
|
{
|
|
enum bpf_cgroup_storage_type stype;
|
|
struct bpf_map *map;
|
|
|
|
if (!storage)
|
|
return;
|
|
|
|
map = &storage->map->map;
|
|
stype = cgroup_storage_type(map);
|
|
if (stype == BPF_CGROUP_STORAGE_SHARED)
|
|
call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
|
|
else
|
|
call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);
|
|
}
|
|
|
|
void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
|
|
struct cgroup *cgroup,
|
|
enum bpf_attach_type type)
|
|
{
|
|
struct bpf_cgroup_storage_map *map;
|
|
|
|
if (!storage)
|
|
return;
|
|
|
|
storage->key.attach_type = type;
|
|
storage->key.cgroup_inode_id = cgroup_id(cgroup);
|
|
|
|
map = storage->map;
|
|
|
|
spin_lock_bh(&map->lock);
|
|
WARN_ON(cgroup_storage_insert(map, storage));
|
|
list_add(&storage->list_map, &map->list);
|
|
list_add(&storage->list_cg, &cgroup->bpf.storages);
|
|
spin_unlock_bh(&map->lock);
|
|
}
|
|
|
|
void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
|
|
{
|
|
struct bpf_cgroup_storage_map *map;
|
|
struct rb_root *root;
|
|
|
|
if (!storage)
|
|
return;
|
|
|
|
map = storage->map;
|
|
|
|
spin_lock_bh(&map->lock);
|
|
root = &map->root;
|
|
rb_erase(&storage->node, root);
|
|
|
|
list_del(&storage->list_map);
|
|
list_del(&storage->list_cg);
|
|
spin_unlock_bh(&map->lock);
|
|
}
|
|
|
|
#endif
|