Commit 91241681 authored Apr 05, 2018 by Michal Hocko Committed by Linus Torvalds Apr 05, 2018

include/linux/mmdebug.h: make VM_WARN* non-rvals



At present the construct

	if (VM_WARN(...))

will compile OK with CONFIG_DEBUG_VM=y and will fail with
CONFIG_DEBUG_VM=n.  The reason is that VM_{WARN,BUG}* have always been
special wrt.  {WARN/BUG}* and never generate any code when DEBUG_VM is
disabled.  So we cannot really use it in conditionals.

We considered changing things so that this construct works in both cases
but that might cause unwanted code generation with CONFIG_DEBUG_VM=n.
It is safer and simpler to make the build fail in both cases.

[akpm@linux-foundation.org: changelog]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 2c7452a0

include/linux/mmdebug.h

+4 −4

Original line number	Diff line number	Diff line
		@@ -37,10 +37,10 @@ void dump_mm(const struct mm_struct *mm);
		BUG(); \
		} \
		} while (0)
		#define VM_WARN_ON(cond) WARN_ON(cond)
		#define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
		#define VM_WARN_ONCE(cond, format...) WARN_ONCE(cond, format)
		#define VM_WARN(cond, format...) WARN(cond, format)
		#define VM_WARN_ON(cond) (void)WARN_ON(cond)
		#define VM_WARN_ON_ONCE(cond) (void)WARN_ON_ONCE(cond)
		#define VM_WARN_ONCE(cond, format...) (void)WARN_ONCE(cond, format)
		#define VM_WARN(cond, format...) (void)WARN(cond, format)
		#else
		#define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
		#define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)

Admin message