mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 18:09:57 +00:00
![Song Liu](/assets/img/avatar_default.png)
To access per-task data, BPF programs usually creates a hash table with pid as the key. This is not ideal because: 1. The user need to estimate the proper size of the hash table, which may be inaccurate; 2. Big hash tables are slow; 3. To clean up the data properly during task terminations, the user need to write extra logic. Task local storage overcomes these issues and offers a better option for these per-task data. Task local storage is only available to BPF_LSM. Now enable it for tracing programs. Unlike LSM programs, tracing programs can be called in IRQ contexts. Helpers that access task local storage are updated to use raw_spin_lock_irqsave() instead of raw_spin_lock_bh(). Tracing programs can attach to functions on the task free path, e.g. exit_creds(). To avoid allocating task local storage after bpf_task_storage_free(). bpf_task_storage_get() is updated to not allocate new storage when the task is not refcounted (task->usage == 0). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: KP Singh <kpsingh@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210225234319.336131-2-songliubraving@fb.com
70 lines
1.4 KiB
C
70 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
|
|
/*
|
|
* Copyright (C) 2020 Google LLC.
|
|
*/
|
|
|
|
#ifndef _LINUX_BPF_LSM_H
|
|
#define _LINUX_BPF_LSM_H
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/bpf.h>
|
|
#include <linux/lsm_hooks.h>
|
|
|
|
#ifdef CONFIG_BPF_LSM
|
|
|
|
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
|
|
RET bpf_lsm_##NAME(__VA_ARGS__);
|
|
#include <linux/lsm_hook_defs.h>
|
|
#undef LSM_HOOK
|
|
|
|
struct bpf_storage_blob {
|
|
struct bpf_local_storage __rcu *storage;
|
|
};
|
|
|
|
extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
|
|
|
|
int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
|
|
const struct bpf_prog *prog);
|
|
|
|
bool bpf_lsm_is_sleepable_hook(u32 btf_id);
|
|
|
|
static inline struct bpf_storage_blob *bpf_inode(
|
|
const struct inode *inode)
|
|
{
|
|
if (unlikely(!inode->i_security))
|
|
return NULL;
|
|
|
|
return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
|
|
}
|
|
|
|
extern const struct bpf_func_proto bpf_inode_storage_get_proto;
|
|
extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
|
|
void bpf_inode_storage_free(struct inode *inode);
|
|
|
|
#else /* !CONFIG_BPF_LSM */
|
|
|
|
static inline bool bpf_lsm_is_sleepable_hook(u32 btf_id)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
|
|
const struct bpf_prog *prog)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
static inline struct bpf_storage_blob *bpf_inode(
|
|
const struct inode *inode)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
static inline void bpf_inode_storage_free(struct inode *inode)
|
|
{
|
|
}
|
|
|
|
#endif /* CONFIG_BPF_LSM */
|
|
|
|
#endif /* _LINUX_BPF_LSM_H */
|