[RFC net-next 1/2] overflow: add DECLARE_FLEX() for on-stack allocs
From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Date: 2023-08-01 11:19:53
Also in:
intel-wired-lan
Subsystem:
kernel hardening (not covered by other areas), the rest · Maintainers:
Kees Cook, Linus Torvalds
Add DECLARE_FLEX() macro for on-stack allocations of structs with flexible array member. Using underlying array for on-stack storage lets us to declare known on compile-time structures without kzalloc(). Actual usage for ice driver is in next patch of the series. Note that "struct" kw and "*" char is moved to the caller, to both: have shorter macro name, and have more natural type specification in the driver code (IOW not hiding an actual type of var). Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> --- include/linux/overflow.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index f9b60313eaea..403b7ec120a2 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h@@ -309,4 +309,18 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) #define struct_size_t(type, member, count) \ struct_size((type *)NULL, member, count) +/** + * DECLARE_FLEX() - Declare an on-stack instance of structure with trailing + * flexible array. + * @type: Pointer to structure type, including "struct" keyword and "*" char. + * @name: Name for a (pointer) variable to create. + * @member: Name of the array member. + * @count: Number of elements in the array; must be compile-time const. + * + * Declare an instance of structure *@type with trailing flexible array. + */ +#define DECLARE_FLEX(type, name, member, count) \ + u8 name##_buf[struct_size((type)NULL, member, count)] __aligned(8) = {};\ + type name = (type)&name##_buf + #endif /* __LINUX_OVERFLOW_H */
--
2.38.1