diff options
author | Andrii Nakryiko <andriin@fb.com> | 2020-09-25 18:13:52 -0700 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-28 17:27:31 -0700 |
commit | 7d9c71e10baa3496d95226aa3bba668f7533ec70 (patch) | |
tree | ec6765ac143da67147fabf28281deee6d8a9050d /tools/lib | |
parent | 192f5a1fe6894dca58d14dc883e6c7030e7267f7 (diff) | |
download | linux-7d9c71e10baa3496d95226aa3bba668f7533ec70.tar.bz2 |
libbpf: Extract generic string hashing function for reuse
Calculating a hash of zero-terminated string is a common need when using
hashmap, so extract it for reuse.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200926011357.2366158-5-andriin@fb.com
Diffstat (limited to 'tools/lib')
-rw-r--r-- | tools/lib/bpf/btf_dump.c | 9 | ||||
-rw-r--r-- | tools/lib/bpf/hashmap.h | 12 |
2 files changed, 13 insertions, 8 deletions
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 6c079b3c8679..91310e528a3a 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -90,14 +90,7 @@ struct btf_dump { static size_t str_hash_fn(const void *key, void *ctx) { - const char *s = key; - size_t h = 0; - - while (*s) { - h = h * 31 + *s; - s++; - } - return h; + return str_hash(key); } static bool str_equal_fn(const void *a, const void *b, void *ctx) diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h index e0af36b0e5d8..d9b385fe808c 100644 --- a/tools/lib/bpf/hashmap.h +++ b/tools/lib/bpf/hashmap.h @@ -25,6 +25,18 @@ static inline size_t hash_bits(size_t h, int bits) #endif } +/* generic C-string hashing function */ +static inline size_t str_hash(const char *s) +{ + size_t h = 0; + + while (*s) { + h = h * 31 + *s; + s++; + } + return h; +} + typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); |