Commit f294b37e authored by Roman Gushchin's avatar Roman Gushchin Committed by Daniel Borkmann
Browse files

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: default avatarRoman Gushchin <guro@fb.com>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 8bad74f9

include/linux/bpf-cgroup.h

+4 −9
Original line number Diff line number Diff line
@@ -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,

kernel/bpf/helpers.c

+6 −2
Original line number Diff line number Diff line
@@ -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 = {

kernel/bpf/local_storage.c

+2 −1
Original line number Diff line number Diff line
@@ -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

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