Konstantin Khlebnikov wrote:
Andrew Morton wrote:
On Thu, 22 Mar 2012 21:28:11 +0000
Al Viro<viro@xxxxxxxxxxxxxxxxxx> wrote:
On Thu, Mar 22, 2012 at 02:26:47PM -0700, Andrew Morton wrote:
It would be nice to find some way of triggering compiler warnings or
sparse warnings if someone mixes a 32-bit type with a vm_flags_t. Any
thoughts on this?
(Maybe that's what __nocast does, but Documentation/sparse.txt doesn't
describe it)
Use __bitwise for that - check how gfp_t is handled.
So what does __nocast do?
Actually it forbid any non-forced casts, but its implementation in sparse seems buggy:
__nocast generates some strange false positives. For example it sometimes forgot about
type attributes in function arguments, I saw this for vm_flags argument in ksm_madvise().
I can reproduce this bug, if somebody interested.
1.c:
# define __nocast __attribute__((nocast))
typedef long __nocast long_t;
static void f(long_t *x)
{
}
static void g(void)
{
long_t x;
f(&x);
}
$ sparse 1.c
1.c:13:12: warning: incorrect type in argument 1 (different modifiers)
1.c:13:12: expected int [nocast] [usertype] *x
1.c:13:12: got int *<noident>
1.c:13:12: warning: implicit cast to nocast type
Is this ok?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>