From 15fa8f425557a0d698f933627771f520ef4ae34b Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave@linux.vnet.ibm.com>
Date: Tue, 24 May 2011 17:11:41 -0700
Subject: [PATCH] include/linux/gfp.h: work around apparent sparse confusion
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@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/gfp.h | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 56d8fc87fbbc..7e8f5d863c76 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -249,14 +249,9 @@ static inline enum zone_type gfp_zone(gfp_t flags)
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;
}
--
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