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| author | Yonghong Song <yhs@fb.com> | 2017-10-23 23:53:08 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-25 10:47:47 +0900 |
| commit | e87c6bc3852b981e71c757be20771546ce9f76f3 (patch) | |
| tree | bad3be630137d8e873f4ad5a1ea77b4aa1853184 /include/linux/bpf.h | |
| parent | 0b4c6841fee03e096b735074a0c4aab3a8e92986 (diff) | |
| download | linux-e87c6bc3852b981e71c757be20771546ce9f76f3.tar.gz linux-e87c6bc3852b981e71c757be20771546ce9f76f3.tar.bz2 linux-e87c6bc3852b981e71c757be20771546ce9f76f3.zip | |
bpf: permit multiple bpf attachments for a single perf event
This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.
A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.
The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/bpf.h')
| -rw-r--r-- | include/linux/bpf.h | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1e334b248ff6..172be7faf7ba 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -273,18 +273,38 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs); int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, __u32 __user *prog_ids, u32 cnt); -#define BPF_PROG_RUN_ARRAY(array, ctx, func) \ +void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs, + struct bpf_prog *old_prog); +int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, + struct bpf_prog *exclude_prog, + struct bpf_prog *include_prog, + struct bpf_prog_array **new_array); + +#define __BPF_PROG_RUN_ARRAY(array, ctx, func, check_non_null) \ ({ \ - struct bpf_prog **_prog; \ + struct bpf_prog **_prog, *__prog; \ + struct bpf_prog_array *_array; \ u32 _ret = 1; \ rcu_read_lock(); \ - _prog = rcu_dereference(array)->progs; \ - for (; *_prog; _prog++) \ - _ret &= func(*_prog, ctx); \ + _array = rcu_dereference(array); \ + if (unlikely(check_non_null && !_array))\ + goto _out; \ + _prog = _array->progs; \ + while ((__prog = READ_ONCE(*_prog))) { \ + _ret &= func(__prog, ctx); \ + _prog++; \ + } \ +_out: \ rcu_read_unlock(); \ _ret; \ }) +#define BPF_PROG_RUN_ARRAY(array, ctx, func) \ + __BPF_PROG_RUN_ARRAY(array, ctx, func, false) + +#define BPF_PROG_RUN_ARRAY_CHECK(array, ctx, func) \ + __BPF_PROG_RUN_ARRAY(array, ctx, func, true) + #ifdef CONFIG_BPF_SYSCALL DECLARE_PER_CPU(int, bpf_prog_active); |