diff options
| -rw-r--r-- | include/linux/string.h | 18 | ||||
| -rw-r--r-- | lib/memcpy_kunit.c | 11 |
2 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h index da490c2154a9..5a36608144a9 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -289,6 +289,24 @@ static inline void memcpy_and_pad(void *dest, size_t dest_len, }) /** + * memset_startat - Set a value starting at a member to the end of a struct + * + * @obj: Address of target struct instance + * @v: Byte value to repeatedly write + * @member: struct member to start writing at + * + * Note that if there is padding between the prior member and the target + * member, memset_after() should be used to clear the prior padding. + */ +#define memset_startat(obj, v, member) \ +({ \ + u8 *__ptr = (u8 *)(obj); \ + typeof(v) __val = (v); \ + memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ + sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ +}) + +/** * str_has_prefix - Test if a string has a given prefix * @str: The string to test * @prefix: The string to see if @str starts with diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c index 5c5b4f3221d9..62f8ffcbbaa3 100644 --- a/lib/memcpy_kunit.c +++ b/lib/memcpy_kunit.c @@ -222,6 +222,13 @@ static void memset_test(struct kunit *test) 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, }, }; + struct some_bytes startat = { + .data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, + 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, + 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, + 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, + }, + }; struct some_bytes dest = { }; int count, value; u8 *ptr; @@ -258,6 +265,10 @@ static void memset_test(struct kunit *test) memset_after(&dest, 0x72, three); compare("memset_after()", dest, after); + /* Verify memset_startat() */ + dest = control; + memset_startat(&dest, 0x79, four); + compare("memset_startat()", dest, startat); #undef TEST_OP } |