[RFC PATCH bpf-next 05/15] bpf: Introduce helpers for container of struct bpf_map
From: Yafang Shao <hidden>
Date: 2022-07-29 15:23:33
Also in:
bpf, linux-mm
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Currently bpf_map_area_alloc() is used to allocate a container of struct
bpf_map or members in this container. To distinguish the map creation
and other members, let split it into two different helpers,
- bpf_map_container_alloc()
Used to allocate a container of struct bpf_map, the container is as
follows,
struct bpf_map_container {
struct bpf_map map; // the map must be the first member
....
};
Pls. note that the struct bpf_map_contianer is a abstract one, which
can be struct bpf_array, struct bpf_bloom_filter and etc.
In this helper, it will call bpf_map_save_memcg() to init memcg
relevant data in the bpf map. And these data will be cleared in
bpf_map_container_free().
- bpf_map_area_alloc()
Now it is used to allocate the members in a contianer only.
Signed-off-by: Yafang Shao <redacted>
---
include/linux/bpf.h | 4 ++++
kernel/bpf/syscall.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 20c26aed7896..2d971b0eb24b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h@@ -1634,9 +1634,13 @@ void bpf_map_inc_with_uref(struct bpf_map *map); struct bpf_map * __must_check bpf_map_inc_not_zero(struct bpf_map *map); void bpf_map_put_with_uref(struct bpf_map *map); void bpf_map_put(struct bpf_map *map); +void *bpf_map_container_alloc(u64 size, int numa_node); +void *bpf_map_container_mmapable_alloc(u64 size, int numa_node, + u32 align, u32 offset); void *bpf_map_area_alloc(u64 size, int numa_node); void *bpf_map_area_mmapable_alloc(u64 size, int numa_node); void bpf_map_area_free(void *base); +void bpf_map_container_free(void *base); bool bpf_map_write_active(const struct bpf_map *map); void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr); int generic_map_lookup_batch(struct bpf_map *map,
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 83c7136c5788..1a1a81a11b37 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c@@ -495,6 +495,62 @@ static void bpf_map_release_memcg(struct bpf_map *map) } #endif +/* + * The return pointer is a bpf_map container, as follow, + * struct bpf_map_container { + * struct bpf_map map; + * ... + * }; + * + * It is used in map creation path. + */ +void *bpf_map_container_alloc(u64 size, int numa_node) +{ + struct bpf_map *map; + void *container; + + container = __bpf_map_area_alloc(size, numa_node, false); + if (!container) + return NULL; + + map = (struct bpf_map *)container; + bpf_map_save_memcg(map); + + return container; +} + +void *bpf_map_container_mmapable_alloc(u64 size, int numa_node, u32 align, + u32 offset) +{ + struct bpf_map *map; + void *container; + void *ptr; + + /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */ + ptr = __bpf_map_area_alloc(size, numa_node, true); + if (!ptr) + return NULL; + + container = ptr + align - offset; + map = (struct bpf_map *)container; + bpf_map_save_memcg(map); + + return ptr; +} + +void bpf_map_container_free(void *container) +{ + struct bpf_map *map; + + if (!container) + return; + + map = (struct bpf_map *)container; + bpf_map_release_memcg(map); + + kvfree(container); +} + static int bpf_map_kptr_off_cmp(const void *a, const void *b) { const struct bpf_map_value_off_desc *off_desc1 = a, *off_desc2 = b;
--
2.17.1