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authorRoman Gushchin <guro@fb.com>2018-09-28 14:45:40 +0000
committerDaniel Borkmann <daniel@iogearbox.net>2018-10-01 16:18:32 +0200
commitf294b37ec7b24a574884cd157497a3748081c0f0 (patch)
treefb5bdf6cf4a5ff61b7a5f84274ae82c123aac7a9 /kernel/bpf/helpers.c
parent8bad74f9840f87661f20ced3dc80c84ab4fd55a1 (diff)
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>
Diffstat (limited to 'kernel/bpf/helpers.c')
-rw-r--r--kernel/bpf/helpers.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 9070b2ace6aa..e42f8789b7ea 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -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 = {