diff options
| author | Anton Protopopov <aspsk@isovalent.com> | 2024-12-13 13:09:28 +0000 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-12-13 14:45:58 -0800 |
| commit | 4e885fab7164689f031a6c73522a3d91674c5bdc (patch) | |
| tree | 8cf0738eed8aec1712d2153ad10ab9cf0193e1e8 | |
| parent | 6a10d2d3613fed501ae9c164cb1c4335e11cb714 (diff) | |
bpf: Add a __btf_get_by_fd helper
Add a new helper to get a pointer to a struct btf from a file
descriptor. This helper doesn't increase a refcnt. Add a comment
explaining this and pointing to a corresponding function which
does take a reference.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241213130934.1087929-2-aspsk@isovalent.com
| -rw-r--r-- | include/linux/bpf.h | 17 | ||||
| -rw-r--r-- | kernel/bpf/btf.c | 11 |
2 files changed, 20 insertions, 8 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index eaee2a819f4c..ac44b857b2f9 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2301,6 +2301,14 @@ void __bpf_obj_drop_impl(void *p, const struct btf_record *rec, bool percpu); struct bpf_map *bpf_map_get(u32 ufd); struct bpf_map *bpf_map_get_with_uref(u32 ufd); +/* + * The __bpf_map_get() and __btf_get_by_fd() functions parse a file + * descriptor and return a corresponding map or btf object. + * Their names are double underscored to emphasize the fact that they + * do not increase refcnt. To also increase refcnt use corresponding + * bpf_map_get() and btf_get_by_fd() functions. + */ + static inline struct bpf_map *__bpf_map_get(struct fd f) { if (fd_empty(f)) @@ -2310,6 +2318,15 @@ static inline struct bpf_map *__bpf_map_get(struct fd f) return fd_file(f)->private_data; } +static inline struct btf *__btf_get_by_fd(struct fd f) +{ + if (fd_empty(f)) + return ERR_PTR(-EBADF); + if (unlikely(fd_file(f)->f_op != &btf_fops)) + return ERR_PTR(-EINVAL); + return fd_file(f)->private_data; +} + void bpf_map_inc(struct bpf_map *map); void bpf_map_inc_with_uref(struct bpf_map *map); struct bpf_map *__bpf_map_inc_not_zero(struct bpf_map *map, bool uref); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index e7a59e6462a9..2ef4fef71910 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -7746,14 +7746,9 @@ struct btf *btf_get_by_fd(int fd) struct btf *btf; CLASS(fd, f)(fd); - if (fd_empty(f)) - return ERR_PTR(-EBADF); - - if (fd_file(f)->f_op != &btf_fops) - return ERR_PTR(-EINVAL); - - btf = fd_file(f)->private_data; - refcount_inc(&btf->refcnt); + btf = __btf_get_by_fd(f); + if (!IS_ERR(btf)) + refcount_inc(&btf->refcnt); return btf; } |