diff mbox

HID: core: don't use negative operands when shift

Message ID 1420586235-27660-1-git-send-email-andy.shevchenko@gmail.com (mailing list archive)
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

Andy Shevchenko Jan. 6, 2015, 11:17 p.m. UTC 
The recent C standard in 6.5.7 paragraph 4 defines that operands for
bitwise shift operators should be non-negative, otherwise it's an
undefined behaviour.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 drivers/hid/hid-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index f2a4879..99307f0 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1027,7 +1027,7 @@  static s32 snto32(__u32 value, unsigned n)
 	case 16: return ((__s16)value);
 	case 32: return ((__s32)value);
 	}
-	return value & (1 << (n - 1)) ? value | (-1 << n) : value;
+	return value & (1 << (n - 1)) ? value | (~0U << n) : value;
 }
 
 s32 hid_snto32(__u32 value, unsigned n)