Right now struct_size() will over-estimate in the cases where flexible arrays start within the struct (rather than exactly at the end). This isn't ideal, but is currently "just" a few bytes of extra space for allocations, etc. There is a risk of pathological problems, though, so it'd be better to make sure the macro can correctly handle weird structure layouts.
Perhaps something like this, adjusted to use size_mul(), size_add(), etc:
if (offsetof(typeof(p), member) == sizeof(*p)) {
/* flexible array exactly aligned at end of struct */
size = sizeof(*p) + count * sizeof(*p->member);
} else if (offsetof(typeof(p), member) < sizeof(*p)) {
/* flexible array starts before end of struct */
size = offsetof(typeof(p), member) + count * sizeof(*p->member);
if (size < sizeof(*p))
size = sizeof(*p);
} else {
BUILD_BUG_ON(offsetof(typeof(p), member) > sizeof(*p));
}
Right now
struct_size()
will over-estimate in the cases where flexible arrays start within the struct (rather than exactly at the end). This isn't ideal, but is currently "just" a few bytes of extra space for allocations, etc. There is a risk of pathological problems, though, so it'd be better to make sure the macro can correctly handle weird structure layouts.Perhaps something like this, adjusted to use
size_mul()
,size_add()
, etc: