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bpf: extend bpf_prog_array to store pointers to the cgroup storage

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This patch converts bpf_prog_array from an array of prog pointers
to the array of struct bpf_prog_array_item elements.

This allows to save a cgroup storage pointer for each bpf program
efficiently attached to a cgroup.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Roman Gushchin
2018-08-02 14:27:21 -07:00
committed by Daniel Borkmann
parent d7bf2c10af
commit 394e40a297
4 changed files with 70 additions and 56 deletions
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19
include/linux/bpf.h
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@@ -349,9 +349,14 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
* The 'struct bpf_prog_array *' should only be replaced with xchg()
* since other cpus are walking the array of pointers in parallel.
*/
struct bpf_prog_array_item {
struct bpf_prog *prog;
struct bpf_cgroup_storage *cgroup_storage;
};
struct bpf_prog_array {
struct rcu_head rcu;
struct bpf_prog *progs[0];
struct bpf_prog_array_item items[0];
};
struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags);
@@ -372,7 +377,8 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
#define __BPF_PROG_RUN_ARRAY(array, ctx, func, check_non_null) \
({ \
struct bpf_prog **_prog, *__prog; \
struct bpf_prog_array_item *_item; \
struct bpf_prog *_prog; \
struct bpf_prog_array *_array; \
u32 _ret = 1; \
preempt_disable(); \
@@ -380,10 +386,11 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
_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++; \
_item = &_array->items[0]; \
while ((_prog = READ_ONCE(_item->prog))) { \
bpf_cgroup_storage_set(_item->cgroup_storage); \
_ret &= func(_prog, ctx); \
_item++; \
} \
_out: \
rcu_read_unlock(); \