diff mbox series

[17/38] backports: define __is_constexpr() for older kernels

Message ID 20221011230356.1c8492a8a107.Ib82d1b3349ab6fc55b5f17dba1ada60601dcd742@changeid (mailing list archive)
State New, archived
Headers show
Series backports updates | expand

Commit Message

Johannes Berg Oct. 11, 2022, 9:04 p.m. UTC 
From: Gregory Greenman <gregory.greenman@intel.com>

type=maint
ticket=none

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
---
 backport/backport-include/linux/kernel.h | 11 +++++++++++
 1 file changed, 11 insertions(+)
diff mbox series

Patch

diff --git a/backport/backport-include/linux/kernel.h b/backport/backport-include/linux/kernel.h
index 36bb755e353c..2555e3c4a0a8 100644
--- a/backport/backport-include/linux/kernel.h
+++ b/backport/backport-include/linux/kernel.h
@@ -5,6 +5,17 @@ 
 #include <linux/bug.h>
 #include <linux/version.h>
 
+#if LINUX_VERSION_IS_LESS(4,17,0)
+
+/*
+ * This returns a constant expression while determining if an argument is
+ * a constant expression, most importantly without evaluating the argument.
+ * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
+ */
+#define __is_constexpr(x) \
+	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
+
+#endif /* < 4.17.0 */
 
 #if LINUX_VERSION_IS_LESS(4,6,0)
 #define kstrtobool LINUX_BACKPORT(kstrtobool)