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bpf: rework cgroup storage pointer passing 

To simplify the following introduction of per-cpu cgroup storage,
let's rework a bit a mechanism of passing a pointer to a cgroup
storage into the bpf_get_local_storage(). Let's save a pointer
to the corresponding bpf_cgroup_storage structure, instead of
a pointer to the actual buffer.

It will help us to handle per-cpu storage later, which has
a different way of accessing to the actual data.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
hifive-unleashed-5.1
Roman Gushchin 2018-09-28 14:45:40 +00:00 committed by Daniel Borkmann
parent 8bad74f984
commit f294b37ec7
3 changed files with 12 additions and 12 deletions
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13
include/linux/bpf-cgroup.h
View File

@ -23,7 +23,8 @@ struct bpf_cgroup_storage;
extern struct static_key_false cgroup_bpf_enabled_key;
#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
DECLARE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
DECLARE_PER_CPU(struct bpf_cgroup_storage*,
bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
#define for_each_cgroup_storage_type(stype) \
for (stype = 0; stype < MAX_BPF_CGROUP_STORAGE_TYPE; stype++)
@ -115,15 +116,9 @@ static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage
*storage[MAX_BPF_CGROUP_STORAGE_TYPE])
{
enum bpf_cgroup_storage_type stype;
struct bpf_storage_buffer *buf;
for_each_cgroup_storage_type(stype) {
if (!storage[stype])
continue;
buf = READ_ONCE(storage[stype]->buf);
this_cpu_write(bpf_cgroup_storage[stype], &buf->data[0]);
}
for_each_cgroup_storage_type(stype)
this_cpu_write(bpf_cgroup_storage[stype], storage[stype]);
}
struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,

8
kernel/bpf/helpers.c
View File

@ -195,7 +195,8 @@ const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
};
#ifdef CONFIG_CGROUP_BPF
DECLARE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
DECLARE_PER_CPU(struct bpf_cgroup_storage*,
bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
{
@ -204,8 +205,11 @@ BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
* verifier checks that its value is correct.
*/
enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
struct bpf_cgroup_storage *storage;
return (unsigned long) this_cpu_read(bpf_cgroup_storage[stype]);
storage = this_cpu_read(bpf_cgroup_storage[stype]);
return (unsigned long)&READ_ONCE(storage->buf)->data[0];
}
const struct bpf_func_proto bpf_get_local_storage_proto = {

3
kernel/bpf/local_storage.c
View File

@ -7,7 +7,8 @@
#include <linux/rbtree.h>
#include <linux/slab.h>
DEFINE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
DEFINE_PER_CPU(struct bpf_cgroup_storage*,
bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
#ifdef CONFIG_CGROUP_BPF