@@ -28,6 +28,7 @@
#include <linux/list.h>
#include <linux/overflow.h>
#include <linux/sched.h>
+#include <linux/stringify.h>
#include <linux/types.h>
#include <linux/workqueue.h>
@@ -469,6 +470,9 @@ static inline bool timer_expired(const struct timer_list *t)
*
* Returns 0 if @config is 0, 1 if set to any value.
*/
-#define IS_CONFIG_NONZERO(config) ((config) != 0)
+#define IS_CONFIG_NONZERO(config) ( \
+ (__stringify_1(config)[0] > '0' && __stringify_1(config)[0] < '9') || \
+ __stringify_1(config)[0] == '-' \
+)
#endif /* !__I915_UTILS_H */
Like the IS_ENABLED() counterpart, we can make IS_CONFIG_NONZERO() to return the right thing when the config is not defined rather than a build error, with the limitation that it can't be used on preprocessor context. The trick here is that macro names can't start with a number or dash, so we stringify the argument and check that the first char is a number != 0 (or starting with a dash to cover negative numbers). Except for -O0 builds the strings are all eliminated. Taking CONFIG_DRM_I915_REQUEST_TIMEOUT in drivers/gpu/drm/i915/gem/i915_gem_context.c as example, we have the following output of the preprocessor: old: if (((20000) != 0) && new: if (( ("20000"[0] > '0' && "20000"[0] < '9') || "20000"[0] == '-' ) && New one looks worse, but is also eliminated from the object: $ size drivers/gpu/drm/i915/gem/i915_gem_context.o.* text data bss dec hex filename 52021 1070 232 53323 d04b drivers/gpu/drm/i915/gem/i915_gem_context.o.new 52021 1070 232 53323 d04b drivers/gpu/drm/i915/gem/i915_gem_context.o.old Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com> --- drivers/gpu/drm/i915/i915_utils.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)