Running sparse on page_alloc.c today, it errors out:
include/linux/gfp.h:254:17: error: bad constant expression
include/linux/gfp.h:254:17: error: cannot size expression
which is a line in gfp_zone():
BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
That's really unfortunate, because it ends up hiding all of the other
legitimate sparse messages like this:
mm/page_alloc.c:5315:59: warning: incorrect type in argument 1 (different base types)
mm/page_alloc.c:5315:59: expected unsigned long [unsigned] [usertype] size
mm/page_alloc.c:5315:59: got restricted gfp_t [usertype] <noident>
...
Having sparse be able to catch these very oopsable bugs is a lot more
important than keeping a BUILD_BUG_ON(). Kill the BUILD_BUG_ON().
Compiles on x86_64 with and without CONFIG_DEBUG_VM=y. defconfig
boots fine for me.
Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
---
linux-2.6.git-dave/include/linux/gfp.h | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff -puN include/linux/gfp.h~make-sparse-happy-with-gfp_h include/linux/gfp.h
--- linux-2.6.git/include/linux/gfp.h~make-sparse-happy-with-gfp_h 2011-04-14 14:47:02.629275904 -0700
+++ linux-2.6.git-dave/include/linux/gfp.h 2011-04-14 14:47:38.813272674 -0700
@@ -249,14 +249,9 @@ static inline enum zone_type gfp_zone(gf
z = (GFP_ZONE_TABLE >> (bit * ZONES_SHIFT)) &
((1 << ZONES_SHIFT) - 1);
-
- if (__builtin_constant_p(bit))
- BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
- else {
#ifdef CONFIG_DEBUG_VM
- BUG_ON((GFP_ZONE_BAD >> bit) & 1);
+ BUG_ON((GFP_ZONE_BAD >> bit) & 1);
#endif
- }
return z;
}
_
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx 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>