[ezy]

Most of the article is devoted to complications related to handling arrays that are inline at the tail of existing structs that usually are layout and size sensitive. Hence the related two restrictions that the count variable keep the same name and location in the struct, and there is no explicit array head pointer (just the implicit location at which the array starts at the end of the struct).

The reasoning most likely being that a bunch of annotations to structs, and perhaps some changes to calls to kmalloc() would be less destructive and much simpler than breaking the kernel ABI and altering the base size of any struct that used that idiom while also having to change every for loop or whatnot in the kernel that uses an explicit counter member name.