[PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

When debugfs is disabled, including panthor_gem.h causes warnings
about a non-static global function defined in a header:

In file included from drivers/gpu/drm/panthor/panthor_drv.c:30:
drivers/gpu/drm/panthor/panthor_gem.h:222:6: error: no previous prototype for 'panthor_gem_debugfs_set_usage_flags' [-Werror=missing-prototypes]
  222 | void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};

This could be changed to a static inline function, but as the normal
one is also static inline, just move the #ifdef check in there.
The #ifdef is still needed to avoid accessing a struct member that
does not exist without debugfs.

Fixes: a3707f53eb3f ("drm/panthor: show device-wide list of DRM GEM objects over DebugFS")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/panthor/panthor_gem.h | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
index 4641994ddd7f..693842e10dee 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.h
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -209,17 +209,14 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
 
 void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
 
-#ifdef CONFIG_DEBUG_FS
 void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
 				   struct seq_file *m);
 static inline void
 panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags)
 {
+#ifdef CONFIG_DEBUG_FS
 	bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
-}
-
-#else
-void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
 #endif
+}
 
 #endif /* __PANTHOR_GEM_H__ */
-- 
2.39.5

Re: [PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[Boris Brezillon]

On Thu, 24 Apr 2025 13:25:47 +0200
Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> When debugfs is disabled, including panthor_gem.h causes warnings
> about a non-static global function defined in a header:
> 
> In file included from drivers/gpu/drm/panthor/panthor_drv.c:30:
> drivers/gpu/drm/panthor/panthor_gem.h:222:6: error: no previous prototype for 'panthor_gem_debugfs_set_usage_flags' [-Werror=missing-prototypes]
>   222 | void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
> 
> This could be changed to a static inline function, but as the normal
> one is also static inline, just move the #ifdef check in there.
> The #ifdef is still needed to avoid accessing a struct member that
> does not exist without debugfs.
> 
> Fixes: a3707f53eb3f ("drm/panthor: show device-wide list of DRM GEM objects over DebugFS")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/gpu/drm/panthor/panthor_gem.h | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
> index 4641994ddd7f..693842e10dee 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.h
> +++ b/drivers/gpu/drm/panthor/panthor_gem.h
> @@ -209,17 +209,14 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
>  
>  void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
>  
> -#ifdef CONFIG_DEBUG_FS
>  void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
>  				   struct seq_file *m);
>  static inline void
>  panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags)
>  {
> +#ifdef CONFIG_DEBUG_FS
>  	bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
> -}
> -
> -#else
> -void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
>  #endif
> +}
>  

Oops. I actually don't see a good reason to expose this function, so
could we go for something like that instead?

diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
index 2dcf308094b2..962c2dc075db 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.c
+++ b/drivers/gpu/drm/panthor/panthor_gem.c
@@ -42,11 +42,20 @@ static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo)
        mutex_unlock(&ptdev->gems.lock);
 }
 
+static void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo,
+                                               u32 usage_flags)
+{
+       bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
+}
 #else
 static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,
                                       struct panthor_gem_object *bo)
 {}
 static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
+static void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo,
+                                               u32 usage_flags)
+{
+}
 #endif
 
 static void panthor_gem_free_object(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
index 4641994ddd7f..4dd732dcd59f 100644
--- a/drivers/gpu/drm/panthor/panthor_gem.h
+++ b/drivers/gpu/drm/panthor/panthor_gem.h
@@ -212,14 +212,6 @@ void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
 #ifdef CONFIG_DEBUG_FS
 void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
                                   struct seq_file *m);
-static inline void
-panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags)
-{
-       bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
-}
-
-#else
-void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
 #endif
 
 #endif /* __PANTHOR_GEM_H__ */

Re: [PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[Arnd Bergmann]

On Thu, Apr 24, 2025, at 13:41, Boris Brezillon wrote:
> On Thu, 24 Apr 2025 13:25:47 +0200
>> +#ifdef CONFIG_DEBUG_FS
>>  	bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
>> -}
>> -
>> -#else
>> -void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
>>  #endif
>> +}
>>  
>
> Oops. I actually don't see a good reason to expose this function, so
> could we go for something like that instead?

I think moving it into pantor_gem.c makes sense, and it certainly
avoids the build warning.

>  #else
>  static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,
>                                        struct panthor_gem_object *bo)
>  {}
>  static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
> +static void panthor_gem_debugfs_set_usage_flags(struct 
> panthor_gem_object *bo,
> +                                               u32 usage_flags)
> +{

Side note: I think the panthor_gem_debugfs_bo_{add,rm} stubs could
actually be replaced with an IS_ENABLED() check in the normal
functions, but that wouldn't work for
panthor_gem_debugfs_set_usage_flags or
panthor_gem_debugfs_print_bos().

    Arnd

Re: [PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[Boris Brezillon]

On Thu, 24 Apr 2025 14:10:16 +0200
"Arnd Bergmann" <arnd@arndb.de> wrote:

> On Thu, Apr 24, 2025, at 13:41, Boris Brezillon wrote:
> > On Thu, 24 Apr 2025 13:25:47 +0200  
> >> +#ifdef CONFIG_DEBUG_FS
> >>  	bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
> >> -}
> >> -
> >> -#else
> >> -void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
> >>  #endif
> >> +}
> >>    
> >
> > Oops. I actually don't see a good reason to expose this function, so
> > could we go for something like that instead?  
> 
> I think moving it into pantor_gem.c makes sense, and it certainly
> avoids the build warning.
> 
> >  #else
> >  static void panthor_gem_debugfs_bo_add(struct panthor_device *ptdev,
> >                                        struct panthor_gem_object *bo)
> >  {}
> >  static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
> > +static void panthor_gem_debugfs_set_usage_flags(struct 
> > panthor_gem_object *bo,
> > +                                               u32 usage_flags)
> > +{  
> 
> Side note: I think the panthor_gem_debugfs_bo_{add,rm} stubs could
> actually be replaced with an IS_ENABLED() check in the normal
> functions, but that wouldn't work for
> panthor_gem_debugfs_set_usage_flags or
> panthor_gem_debugfs_print_bos().

Yeah, I think I prefer consistency over saving a few LoC ;-).
Do you plan to send a v2 with the suggested changes, or should we take
care of that?

Re: [PATCH] drm/panthor: fix building without CONFIG_DEBUG_FS

[Adrián Larumbe]

Hi Arnd,

Thanks for the fix. I've already submitted a second attempt because I thought the build being broken
is something we ought to deal with ASAP. I've added you as a bug reporter and also made mention
of this thread in the new patch.

Kind Regards,
Adrian

On 24.04.2025 13:25, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> When debugfs is disabled, including panthor_gem.h causes warnings
> about a non-static global function defined in a header:
>
> In file included from drivers/gpu/drm/panthor/panthor_drv.c:30:
> drivers/gpu/drm/panthor/panthor_gem.h:222:6: error: no previous prototype for 'panthor_gem_debugfs_set_usage_flags' [-Werror=missing-prototypes]
>   222 | void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
>
> This could be changed to a static inline function, but as the normal
> one is also static inline, just move the #ifdef check in there.
> The #ifdef is still needed to avoid accessing a struct member that
> does not exist without debugfs.
>
> Fixes: a3707f53eb3f ("drm/panthor: show device-wide list of DRM GEM objects over DebugFS")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/gpu/drm/panthor/panthor_gem.h | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
> index 4641994ddd7f..693842e10dee 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.h
> +++ b/drivers/gpu/drm/panthor/panthor_gem.h
> @@ -209,17 +209,14 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
>
>  void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
>
> -#ifdef CONFIG_DEBUG_FS
>  void panthor_gem_debugfs_print_bos(struct panthor_device *pfdev,
>  				   struct seq_file *m);
>  static inline void
>  panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags)
>  {
> +#ifdef CONFIG_DEBUG_FS
>  	bo->debugfs.flags = usage_flags | PANTHOR_DEBUGFS_GEM_USAGE_FLAG_INITIALIZED;
> -}
> -
> -#else
> -void panthor_gem_debugfs_set_usage_flags(struct panthor_gem_object *bo, u32 usage_flags) {};
>  #endif
> +}
>
>  #endif /* __PANTHOR_GEM_H__ */
> --
> 2.39.5