Re: + expose-range-checking-functions-from-arch-specific.patch added to -mm tree

[David Howells <dhowells@redhat.com>]

Rusty Russell <rusty@rustcorp.com.au> wrote:

> static inline bool range_over_limit(unsigned long start,
> 				    unsigned long len,
> 				    unsigned long limit)

I'm still not sure the name is entirely clear, but it's better.  I'd still
stick the word "check" in there personally, perhaps check_range_limit(), but
that's just my preference.

> PS.  Previously this identical function was called __range_ok() (and
> returned 0 if it was not ok...)

Ummm...  Didn't __range_ok() implicitly involve get_addr_limit() rather than
taking an explicit range?  Certainly i386 thinks so:

#define __range_ok(addr,size) ({ \
	unsigned long flag,roksum; \
	__chk_user_ptr(addr); \
	asm("addl %3,%1 ; sbbl %0,%0; cmpl %1,%4; sbbl $0,%0" \
		:"=&r" (flag), "=r" (roksum) \
		:"1" (addr),"g" ((int)(size)),"rm" (current_thread_info()->addr_limit.seg)); \
	flag; })

David