[PATCH] lockdep: change 'static const' variables to enum values

[PATCH] lockdep: change 'static const' variables to enum values

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

gcc warns about 'static const' variables even in headers when building
with -Wunused-const-variables enabled:

In file included from kernel/locking/lockdep_proc.c:25:
kernel/locking/lockdep_internals.h:69:28: error: 'LOCKF_USED_IN_IRQ_READ' defined but not used [-Werror=unused-const-variable=]
   69 | static const unsigned long LOCKF_USED_IN_IRQ_READ =
      |                            ^~~~~~~~~~~~~~~~~~~~~~
kernel/locking/lockdep_internals.h:63:28: error: 'LOCKF_ENABLED_IRQ_READ' defined but not used [-Werror=unused-const-variable=]
   63 | static const unsigned long LOCKF_ENABLED_IRQ_READ =
      |                            ^~~~~~~~~~~~~~~~~~~~~~
kernel/locking/lockdep_internals.h:57:28: error: 'LOCKF_USED_IN_IRQ' defined but not used [-Werror=unused-const-variable=]
   57 | static const unsigned long LOCKF_USED_IN_IRQ =
      |                            ^~~~~~~~~~~~~~~~~
kernel/locking/lockdep_internals.h:51:28: error: 'LOCKF_ENABLED_IRQ' defined but not used [-Werror=unused-const-variable=]
   51 | static const unsigned long LOCKF_ENABLED_IRQ =
      |                            ^~~~~~~~~~~~~~~~~

This one is easy to avoid by changing the generated constant definition
into an equivalent enum.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/locking/lockdep_internals.h | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 20f9ef58d3d0..8b4cd6540e49 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -47,29 +47,31 @@ enum {
 	__LOCKF(USED_READ)
 };
 
+enum {
 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE |
-static const unsigned long LOCKF_ENABLED_IRQ =
+	LOCKF_ENABLED_IRQ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE |
-static const unsigned long LOCKF_USED_IN_IRQ =
+	LOCKF_USED_IN_IRQ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE##_READ |
-static const unsigned long LOCKF_ENABLED_IRQ_READ =
+	LOCKF_ENABLED_IRQ_READ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE##_READ |
-static const unsigned long LOCKF_USED_IN_IRQ_READ =
+	LOCKF_USED_IN_IRQ_READ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
+};
 
 #define LOCKF_ENABLED_IRQ_ALL (LOCKF_ENABLED_IRQ | LOCKF_ENABLED_IRQ_READ)
 #define LOCKF_USED_IN_IRQ_ALL (LOCKF_USED_IN_IRQ | LOCKF_USED_IN_IRQ_READ)
-- 
2.39.5

Re: [PATCH] lockdep: change 'static const' variables to enum values

[Andy Shevchenko]

On Tue, Feb 25, 2025 at 09:08:26PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcc warns about 'static const' variables even in headers when building
> with -Wunused-const-variables enabled:
> 
> In file included from kernel/locking/lockdep_proc.c:25:
> kernel/locking/lockdep_internals.h:69:28: error: 'LOCKF_USED_IN_IRQ_READ' defined but not used [-Werror=unused-const-variable=]
>    69 | static const unsigned long LOCKF_USED_IN_IRQ_READ =
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> kernel/locking/lockdep_internals.h:63:28: error: 'LOCKF_ENABLED_IRQ_READ' defined but not used [-Werror=unused-const-variable=]
>    63 | static const unsigned long LOCKF_ENABLED_IRQ_READ =
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> kernel/locking/lockdep_internals.h:57:28: error: 'LOCKF_USED_IN_IRQ' defined but not used [-Werror=unused-const-variable=]
>    57 | static const unsigned long LOCKF_USED_IN_IRQ =
>       |                            ^~~~~~~~~~~~~~~~~
> kernel/locking/lockdep_internals.h:51:28: error: 'LOCKF_ENABLED_IRQ' defined but not used [-Werror=unused-const-variable=]
>    51 | static const unsigned long LOCKF_ENABLED_IRQ =
>       |                            ^~~~~~~~~~~~~~~~~
> 
> This one is easy to avoid by changing the generated constant definition
> into an equivalent enum.

Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko