[PATCH 0/2] staging: vc04_services: address W=1 warnings

[PATCH 0/2] staging: vc04_services: address W=1 warnings

[Gaston Gonzalez]

This set comprises two patches that fix two "no previous prototype"
warnings in vc04_services.

Gaston Gonzalez (2):
  staging: vchiq_arm: make vchiq_platform_get_arm_state() static
  staging: vchiq_arm: add prototype of function vchiq_platform_init()

 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +--
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h | 2 ++
 2 files changed, 3 insertions(+), 2 deletions(-)

-- 
2.35.1

[PATCH 1/2] staging: vchiq_arm: make vchiq_platform_get_arm_state() static

[Gaston Gonzalez]

Fix "no previous prototype" W=1 warning by making the function
vchiq_platform_get_arm_state() static.

While at it, realign the function declaration in one line and reposition
the asterisk symbol to fulfill the 'foo *bar' syntax.

Signed-off-by: Gaston Gonzalez <gascoar@gmail.com>
---
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 54ab6208ddae..f0bfacfdea80 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -593,8 +593,7 @@ vchiq_platform_init_state(struct vchiq_state *state)
 	return 0;
 }
 
-struct vchiq_arm_state*
-vchiq_platform_get_arm_state(struct vchiq_state *state)
+static struct vchiq_arm_state *vchiq_platform_get_arm_state(struct vchiq_state *state)
 {
 	struct vchiq_2835_state *platform_state;
 
-- 
2.35.1

[PATCH 2/2] staging: vchiq_arm: add prototype of function vchiq_platform_init()

[Gaston Gonzalez]

Fix "no previous prototype" W=1 warning by adding the prototype of the
function vchiq_platform_init().

Note: vchiq_platform_init() is only called once in vchiq_probe(), so
presumably should be static function. However, making the function
static breaks the build.

Signed-off-by: Gaston Gonzalez <gascoar@gmail.com>
---
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
index 2aa46b119a46..d72edaf7e5e9 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
@@ -122,6 +122,8 @@ vchiq_instance_get_trace(struct vchiq_instance *instance);
 extern void
 vchiq_instance_set_trace(struct vchiq_instance *instance, int trace);
 
+int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state *state);
+
 #if IS_ENABLED(CONFIG_VCHIQ_CDEV)
 
 extern void
-- 
2.35.1

Re: [PATCH 2/2] staging: vchiq_arm: add prototype of function vchiq_platform_init()

[Dan Carpenter]

On Wed, Mar 02, 2022 at 06:36:38PM -0300, Gaston Gonzalez wrote:
> Fix "no previous prototype" W=1 warning by adding the prototype of the
> function vchiq_platform_init().
> 
> Note: vchiq_platform_init() is only called once in vchiq_probe(), so
> presumably should be static function. However, making the function
> static breaks the build.
> 

That's weird.  I don't have an ARM cross compile set up.  How does the
build break?

regards,
dan carpenter

Re: [PATCH 2/2] staging: vchiq_arm: add prototype of function vchiq_platform_init()

[Gaston Gonzalez]

On Thu, Mar 03, 2022 at 03:25:47PM +0300, Dan Carpenter wrote:
> On Wed, Mar 02, 2022 at 06:36:38PM -0300, Gaston Gonzalez wrote:
> > Fix "no previous prototype" W=1 warning by adding the prototype of the
> > function vchiq_platform_init().
> > 
> > Note: vchiq_platform_init() is only called once in vchiq_probe(), so
> > presumably should be static function. However, making the function
> > static breaks the build.
> > 
> 
> That's weird.  I don't have an ARM cross compile set up.  How does the
> build break?
> 
> regards,
> dan carpenter
>

Hi Dan,

Test building the driver in x86 I get the error pasted below.

However, now that you mention it, I made an ARM (64 bit) cross
compilation: making the function static builds OK without the warning.
I'll to do the same for a 32 bit setup.

So I suppose that making the function static is the right approach ?

FWIW, branch and cross-compiler:

- Remote: https://github.com/raspberrypi/linux.git
- Branch: rpi-5.17.y
- gcc: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110


-> x86 build error:

CC [M]  drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.o
In function ‘free_pagelist’,
    inlined from ‘vchiq_complete_bulk’ at drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:650:3:
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:434:4: error: argument 2 null where non-null expected [-Werror=nonnull]
  434 |    memcpy((char *)kmap(pages[0]) +
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  435 |     pagelist->offset,
      |     ~~~~~~~~~~~~~~~~~
  436 |     fragments,
      |     ~~~~~~~~~~
  437 |     head_bytes);
      |     ~~~~~~~~~~~
In file included from ./arch/x86/include/asm/string.h:5,
                 from ./include/linux/string.h:20,
                 from ./include/linux/bitmap.h:11,
                 from ./include/linux/cpumask.h:12,
                 from ./arch/x86/include/asm/cpumask.h:5,
                 from ./arch/x86/include/asm/msr.h:11,
                 from ./arch/x86/include/asm/processor.h:22,
                 from ./arch/x86/include/asm/timex.h:5,
                 from ./include/linux/timex.h:65,
                 from ./include/linux/time32.h:13,
                 from ./include/linux/time.h:60,
                 from ./include/linux/stat.h:19,
                 from ./include/linux/module.h:13,
                 from drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:8:
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c: In function ‘vchiq_complete_bulk’:
./arch/x86/include/asm/string_64.h:14:14: note: in a call to function ‘memcpy’ declared here
   14 | extern void *memcpy(void *to, const void *from, size_t len);
      |              ^~~~~~
cc1: all warnings being treated as errors
make[1]: *** [scripts/Makefile.build:288: drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.o] Error 1
make: *** [Makefile:1831: drivers/staging/vc04_services] Error 2

regards,

Gaston

Re: [PATCH 2/2] staging: vchiq_arm: add prototype of function vchiq_platform_init()

[Dan Carpenter]

On Fri, Mar 04, 2022 at 04:30:15PM -0300, Gaston Gonzalez wrote:
> On Thu, Mar 03, 2022 at 03:25:47PM +0300, Dan Carpenter wrote:
> > On Wed, Mar 02, 2022 at 06:36:38PM -0300, Gaston Gonzalez wrote:
> > > Fix "no previous prototype" W=1 warning by adding the prototype of the
> > > function vchiq_platform_init().
> > > 
> > > Note: vchiq_platform_init() is only called once in vchiq_probe(), so
> > > presumably should be static function. However, making the function
> > > static breaks the build.
> > > 
> > 
> > That's weird.  I don't have an ARM cross compile set up.  How does the
> > build break?
> > 
> > regards,
> > dan carpenter
> >
> 
> Hi Dan,
> 
> Test building the driver in x86 I get the error pasted below.
> 
> However, now that you mention it, I made an ARM (64 bit) cross
> compilation: making the function static builds OK without the warning.
> I'll to do the same for a 32 bit setup.
> 
> So I suppose that making the function static is the right approach ?
> 
> FWIW, branch and cross-compiler:
> 
> - Remote: https://github.com/raspberrypi/linux.git
> - Branch: rpi-5.17.y
> - gcc: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110
> 
> 
> -> x86 build error:
> 
> CC [M]  drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.o
> In function ‘free_pagelist’,
>     inlined from ‘vchiq_complete_bulk’ at drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:650:3:
> drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:434:4: error: argument 2 null where non-null expected [-Werror=nonnull]
>   434 |    memcpy((char *)kmap(pages[0]) +
>       |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   435 |     pagelist->offset,
>       |     ~~~~~~~~~~~~~~~~~
>   436 |     fragments,
>       |     ~~~~~~~~~~
>   437 |     head_bytes);
>       |     ~~~~~~~~~~~
> In file included from ./arch/x86/include/asm/string.h:5,
>                  from ./include/linux/string.h:20,
>                  from ./include/linux/bitmap.h:11,
>                  from ./include/linux/cpumask.h:12,
>                  from ./arch/x86/include/asm/cpumask.h:5,
>                  from ./arch/x86/include/asm/msr.h:11,
>                  from ./arch/x86/include/asm/processor.h:22,
>                  from ./arch/x86/include/asm/timex.h:5,
>                  from ./include/linux/timex.h:65,
>                  from ./include/linux/time32.h:13,
>                  from ./include/linux/time.h:60,
>                  from ./include/linux/stat.h:19,
>                  from ./include/linux/module.h:13,
>                  from drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:8:
> drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c: In function ‘vchiq_complete_bulk’:
> ./arch/x86/include/asm/string_64.h:14:14: note: in a call to function ‘memcpy’ declared here
>    14 | extern void *memcpy(void *to, const void *from, size_t len);
>       |              ^~~~~~
> cc1: all warnings being treated as errors
> make[1]: *** [scripts/Makefile.build:288: drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.o] Error 1
> make: *** [Makefile:1831: drivers/staging/vc04_services] Error 2

That's so weird.

1) The GCC warning is a false positive, but -Werror means we have to
   deal with it.
2) I can't explain the false positive.
3) My guess is that making the function static affects how it is inlined
   so it gives the compiler more visibility into how free_pagelist()?
   is called so that's why it gets triggered because of the patch?
4) This is an x86 config and it's an ARM driver, but nothing in the
   Kconfig file says that vchiq_arm needs ARM or raspberry pi.  Should
   there be?  And a COMPILE_TEST option?

Anyway, we don't paper over warnings like this so the patch is not the
correct thing.  Especially we don't paper over it without a giant
comment explaining how we filed a bug with GCC or whatever and a link
to bugzilla and all that other stuff.

regards,
dan carpenter

Re: [PATCH 2/2] staging: vchiq_arm: add prototype of function vchiq_platform_init()

[Greg KH]

On Wed, Mar 02, 2022 at 06:36:38PM -0300, Gaston Gonzalez wrote:
> Fix "no previous prototype" W=1 warning by adding the prototype of the
> function vchiq_platform_init().
> 
> Note: vchiq_platform_init() is only called once in vchiq_probe(), so
> presumably should be static function. However, making the function
> static breaks the build.
> 
> Signed-off-by: Gaston Gonzalez <gascoar@gmail.com>
> ---
>  drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> index 2aa46b119a46..d72edaf7e5e9 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
> @@ -122,6 +122,8 @@ vchiq_instance_get_trace(struct vchiq_instance *instance);
>  extern void
>  vchiq_instance_set_trace(struct vchiq_instance *instance, int trace);
>  
> +int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state *state);
> +

It is a static function, so don't add a prototype here to say it is not
:(

thanks,

greg k-h