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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2025-04-22 15:05:18 -0600 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2025-05-08 09:42:05 -0700 |
| commit | 190faecf64c54bb5f9d8f0ea2a6628078d0f2c83 (patch) | |
| tree | 335a946e7b7120a9689cebcb0f2fa8cad3cd3b88 | |
| parent | ccf1d2b4a1d9ef4287ff51e634c626fd4683b10c (diff) | |
overflow: Add STACK_FLEX_ARRAY_SIZE() helper
Add new STACK_FLEX_ARRAY_SIZE() helper to get the size of a
flexible-array member defined using DEFINE_FLEX()/DEFINE_RAW_FLEX()
at compile time.
This is essentially the same as ARRAY_SIZE() but for on-stack
flexible-array members.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/83d53744e11c80eb3f03765238cbe648855f4168.1745355442.git.gustavoars@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
| -rw-r--r-- | include/linux/overflow.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 6ee67c20b575..f33d74dac06f 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -420,6 +420,8 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * flexible array member. * Use __struct_size(@name) to get compile-time size of it afterwards. * Use __member_size(@name->member) to get compile-time size of @name members. + * Use STACK_FLEX_ARRAY_SIZE(@name, @member) to get compile-time number of + * elements in array @member. */ #define DEFINE_RAW_FLEX(type, name, member, count) \ _DEFINE_FLEX(type, name, member, count, = {}) @@ -438,8 +440,21 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * flexible array member. * Use __struct_size(@NAME) to get compile-time size of it afterwards. * Use __member_size(@NAME->member) to get compile-time size of @NAME members. + * Use STACK_FLEX_ARRAY_SIZE(@name, @member) to get compile-time number of + * elements in array @member. */ #define DEFINE_FLEX(TYPE, NAME, MEMBER, COUNTER, COUNT) \ _DEFINE_FLEX(TYPE, NAME, MEMBER, COUNT, = { .obj.COUNTER = COUNT, }) +/** + * STACK_FLEX_ARRAY_SIZE() - helper macro for DEFINE_FLEX() family. + * Returns the number of elements in @array. + * + * @name: Name for a variable defined in DEFINE_RAW_FLEX()/DEFINE_FLEX(). + * @array: Name of the array member. + */ +#define STACK_FLEX_ARRAY_SIZE(name, array) \ + (__member_size((name)->array) / sizeof(*(name)->array) + \ + __must_be_array((name)->array)) + #endif /* __LINUX_OVERFLOW_H */ |