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| author | Dave Marchevsky <davemarchevsky@fb.com> | 2024-08-13 21:24:23 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-08-23 11:39:33 -0700 |
| commit | b0966c724584a5a9fd7fb529de19807c31f27a45 (patch) | |
| tree | e86b3cdd3565ea6cb866b565cf8503c992be0522 /include/uapi/linux/bpf.h | |
| parent | d59232afb0344e33e9399f308d9b4a03876e7676 (diff) | |
| download | lwn-b0966c724584a5a9fd7fb529de19807c31f27a45.tar.gz lwn-b0966c724584a5a9fd7fb529de19807c31f27a45.zip | |
bpf: Support bpf_kptr_xchg into local kptr
Currently, users can only stash kptr into map values with bpf_kptr_xchg().
This patch further supports stashing kptr into local kptr by adding local
kptr as a valid destination type.
When stashing into local kptr, btf_record in program BTF is used instead
of btf_record in map to search for the btf_field of the local kptr.
The local kptr specific checks in check_reg_type() only apply when the
source argument of bpf_kptr_xchg() is local kptr. Therefore, we make the
scope of the check explicit as the destination now can also be local kptr.
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Link: https://lore.kernel.org/r/20240813212424.2871455-5-amery.hung@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/uapi/linux/bpf.h')
| -rw-r--r-- | include/uapi/linux/bpf.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 35bcf52dbc65..e2629457d72d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5519,11 +5519,12 @@ union bpf_attr { * **-EOPNOTSUPP** if the hash calculation failed or **-EINVAL** if * invalid arguments are passed. * - * void *bpf_kptr_xchg(void *map_value, void *ptr) + * void *bpf_kptr_xchg(void *dst, void *ptr) * Description - * Exchange kptr at pointer *map_value* with *ptr*, and return the - * old value. *ptr* can be NULL, otherwise it must be a referenced - * pointer which will be released when this helper is called. + * Exchange kptr at pointer *dst* with *ptr*, and return the old value. + * *dst* can be map value or local kptr. *ptr* can be NULL, otherwise + * it must be a referenced pointer which will be released when this helper + * is called. * Return * The old value of kptr (which can be NULL). The returned pointer * if not NULL, is a reference which must be released using its |