248 lines
6.2 KiB
C
248 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/bpf.h>
|
|
#include <linux/bpf_local_storage.h>
|
|
#include <uapi/linux/btf.h>
|
|
#include <linux/btf_ids.h>
|
|
|
|
DEFINE_BPF_STORAGE_CACHE(cgroup_cache);
|
|
|
|
static DEFINE_PER_CPU(int, bpf_cgrp_storage_busy);
|
|
|
|
static void bpf_cgrp_storage_lock(void)
|
|
{
|
|
migrate_disable();
|
|
this_cpu_inc(bpf_cgrp_storage_busy);
|
|
}
|
|
|
|
static void bpf_cgrp_storage_unlock(void)
|
|
{
|
|
this_cpu_dec(bpf_cgrp_storage_busy);
|
|
migrate_enable();
|
|
}
|
|
|
|
static bool bpf_cgrp_storage_trylock(void)
|
|
{
|
|
migrate_disable();
|
|
if (unlikely(this_cpu_inc_return(bpf_cgrp_storage_busy) != 1)) {
|
|
this_cpu_dec(bpf_cgrp_storage_busy);
|
|
migrate_enable();
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static struct bpf_local_storage __rcu **cgroup_storage_ptr(void *owner)
|
|
{
|
|
struct cgroup *cg = owner;
|
|
|
|
return &cg->bpf_cgrp_storage;
|
|
}
|
|
|
|
void bpf_cgrp_storage_free(struct cgroup *cgroup)
|
|
{
|
|
struct bpf_local_storage *local_storage;
|
|
bool free_cgroup_storage = false;
|
|
unsigned long flags;
|
|
|
|
rcu_read_lock();
|
|
local_storage = rcu_dereference(cgroup->bpf_cgrp_storage);
|
|
if (!local_storage) {
|
|
rcu_read_unlock();
|
|
return;
|
|
}
|
|
|
|
bpf_cgrp_storage_lock();
|
|
raw_spin_lock_irqsave(&local_storage->lock, flags);
|
|
free_cgroup_storage = bpf_local_storage_unlink_nolock(local_storage);
|
|
raw_spin_unlock_irqrestore(&local_storage->lock, flags);
|
|
bpf_cgrp_storage_unlock();
|
|
rcu_read_unlock();
|
|
|
|
if (free_cgroup_storage)
|
|
kfree_rcu(local_storage, rcu);
|
|
}
|
|
|
|
static struct bpf_local_storage_data *
|
|
cgroup_storage_lookup(struct cgroup *cgroup, struct bpf_map *map, bool cacheit_lockit)
|
|
{
|
|
struct bpf_local_storage *cgroup_storage;
|
|
struct bpf_local_storage_map *smap;
|
|
|
|
cgroup_storage = rcu_dereference_check(cgroup->bpf_cgrp_storage,
|
|
bpf_rcu_lock_held());
|
|
if (!cgroup_storage)
|
|
return NULL;
|
|
|
|
smap = (struct bpf_local_storage_map *)map;
|
|
return bpf_local_storage_lookup(cgroup_storage, smap, cacheit_lockit);
|
|
}
|
|
|
|
static void *bpf_cgrp_storage_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_local_storage_data *sdata;
|
|
struct cgroup *cgroup;
|
|
int fd;
|
|
|
|
fd = *(int *)key;
|
|
cgroup = cgroup_get_from_fd(fd);
|
|
if (IS_ERR(cgroup))
|
|
return ERR_CAST(cgroup);
|
|
|
|
bpf_cgrp_storage_lock();
|
|
sdata = cgroup_storage_lookup(cgroup, map, true);
|
|
bpf_cgrp_storage_unlock();
|
|
cgroup_put(cgroup);
|
|
return sdata ? sdata->data : NULL;
|
|
}
|
|
|
|
static int bpf_cgrp_storage_update_elem(struct bpf_map *map, void *key,
|
|
void *value, u64 map_flags)
|
|
{
|
|
struct bpf_local_storage_data *sdata;
|
|
struct cgroup *cgroup;
|
|
int fd;
|
|
|
|
fd = *(int *)key;
|
|
cgroup = cgroup_get_from_fd(fd);
|
|
if (IS_ERR(cgroup))
|
|
return PTR_ERR(cgroup);
|
|
|
|
bpf_cgrp_storage_lock();
|
|
sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map,
|
|
value, map_flags, GFP_ATOMIC);
|
|
bpf_cgrp_storage_unlock();
|
|
cgroup_put(cgroup);
|
|
return PTR_ERR_OR_ZERO(sdata);
|
|
}
|
|
|
|
static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map)
|
|
{
|
|
struct bpf_local_storage_data *sdata;
|
|
|
|
sdata = cgroup_storage_lookup(cgroup, map, false);
|
|
if (!sdata)
|
|
return -ENOENT;
|
|
|
|
bpf_selem_unlink(SELEM(sdata), true);
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct cgroup *cgroup;
|
|
int err, fd;
|
|
|
|
fd = *(int *)key;
|
|
cgroup = cgroup_get_from_fd(fd);
|
|
if (IS_ERR(cgroup))
|
|
return PTR_ERR(cgroup);
|
|
|
|
bpf_cgrp_storage_lock();
|
|
err = cgroup_storage_delete(cgroup, map);
|
|
bpf_cgrp_storage_unlock();
|
|
cgroup_put(cgroup);
|
|
return err;
|
|
}
|
|
|
|
static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key)
|
|
{
|
|
return -ENOTSUPP;
|
|
}
|
|
|
|
static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
|
|
{
|
|
return bpf_local_storage_map_alloc(attr, &cgroup_cache);
|
|
}
|
|
|
|
static void cgroup_storage_map_free(struct bpf_map *map)
|
|
{
|
|
bpf_local_storage_map_free(map, &cgroup_cache, NULL);
|
|
}
|
|
|
|
/* *gfp_flags* is a hidden argument provided by the verifier */
|
|
BPF_CALL_5(bpf_cgrp_storage_get, struct bpf_map *, map, struct cgroup *, cgroup,
|
|
void *, value, u64, flags, gfp_t, gfp_flags)
|
|
{
|
|
struct bpf_local_storage_data *sdata;
|
|
|
|
WARN_ON_ONCE(!bpf_rcu_lock_held());
|
|
if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
|
|
return (unsigned long)NULL;
|
|
|
|
if (!cgroup)
|
|
return (unsigned long)NULL;
|
|
|
|
if (!bpf_cgrp_storage_trylock())
|
|
return (unsigned long)NULL;
|
|
|
|
sdata = cgroup_storage_lookup(cgroup, map, true);
|
|
if (sdata)
|
|
goto unlock;
|
|
|
|
/* only allocate new storage, when the cgroup is refcounted */
|
|
if (!percpu_ref_is_dying(&cgroup->self.refcnt) &&
|
|
(flags & BPF_LOCAL_STORAGE_GET_F_CREATE))
|
|
sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map,
|
|
value, BPF_NOEXIST, gfp_flags);
|
|
|
|
unlock:
|
|
bpf_cgrp_storage_unlock();
|
|
return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data;
|
|
}
|
|
|
|
BPF_CALL_2(bpf_cgrp_storage_delete, struct bpf_map *, map, struct cgroup *, cgroup)
|
|
{
|
|
int ret;
|
|
|
|
WARN_ON_ONCE(!bpf_rcu_lock_held());
|
|
if (!cgroup)
|
|
return -EINVAL;
|
|
|
|
if (!bpf_cgrp_storage_trylock())
|
|
return -EBUSY;
|
|
|
|
ret = cgroup_storage_delete(cgroup, map);
|
|
bpf_cgrp_storage_unlock();
|
|
return ret;
|
|
}
|
|
|
|
const struct bpf_map_ops cgrp_storage_map_ops = {
|
|
.map_meta_equal = bpf_map_meta_equal,
|
|
.map_alloc_check = bpf_local_storage_map_alloc_check,
|
|
.map_alloc = cgroup_storage_map_alloc,
|
|
.map_free = cgroup_storage_map_free,
|
|
.map_get_next_key = notsupp_get_next_key,
|
|
.map_lookup_elem = bpf_cgrp_storage_lookup_elem,
|
|
.map_update_elem = bpf_cgrp_storage_update_elem,
|
|
.map_delete_elem = bpf_cgrp_storage_delete_elem,
|
|
.map_check_btf = bpf_local_storage_map_check_btf,
|
|
.map_mem_usage = bpf_local_storage_map_mem_usage,
|
|
.map_btf_id = &bpf_local_storage_map_btf_id[0],
|
|
.map_owner_storage_ptr = cgroup_storage_ptr,
|
|
};
|
|
|
|
const struct bpf_func_proto bpf_cgrp_storage_get_proto = {
|
|
.func = bpf_cgrp_storage_get,
|
|
.gpl_only = false,
|
|
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
|
|
.arg1_type = ARG_CONST_MAP_PTR,
|
|
.arg2_type = ARG_PTR_TO_BTF_ID,
|
|
.arg2_btf_id = &bpf_cgroup_btf_id[0],
|
|
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
|
|
.arg4_type = ARG_ANYTHING,
|
|
};
|
|
|
|
const struct bpf_func_proto bpf_cgrp_storage_delete_proto = {
|
|
.func = bpf_cgrp_storage_delete,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_CONST_MAP_PTR,
|
|
.arg2_type = ARG_PTR_TO_BTF_ID,
|
|
.arg2_btf_id = &bpf_cgroup_btf_id[0],
|
|
};
|