Re: [PATCH bpf-next 2/9] bpf: rework cgroup storage pointer passing
From: Song Liu <hidden>
Date: 2018-09-25 06:06:05
Also in:
lkml
On Fri, Sep 21, 2018 at 10:16 AM Roman Gushchin [off-list ref] wrote:
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 <redacted> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <redacted>
quoted hunk ↗ jump to hunk
--- include/linux/bpf-cgroup.h | 13 ++++--------- kernel/bpf/helpers.c | 8 ++++++-- kernel/bpf/local_storage.c | 3 ++- 3 files changed, 12 insertions(+), 12 deletions(-)diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index e9871b012dac..7e0c9a1d48b7 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h@@ -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,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 = {diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index 0bd9f19fc557..6742292fb39e 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c@@ -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 --2.17.1