[PATCH] mdacon: fix redefinition of 'scr_memsetw'

[PATCH] mdacon: fix redefinition of 'scr_memsetw'

[Jackie Liu]

From: Jackie Liu <liuyun01@kylinos.cn>

CONFIG_VGA_CONSOLE=n and CONFIG_MDA_CONSOLE=n will cause vt_buffer.h not
include <asm/vga.h>.

But if we set CONFIG_MDA_CONSOLE=m, mdacon.c include <linux/vt_buffer.h>
is in front of include <asm/vga.h>. VT_BUF_HAVE_MEMSETW is not defined,
so vt_buffer.h will define a scr_memsetw, after that, vga.h also define
a scr_memsetw, so the repeated definition of scr_memsetw appears, builds
error.

We only need to make vt_buffer.h also contain vga.h when
CONFIG_MDA_CONSOLE=m. This problem can be fixed.

BTW, mdacon.c no need to include vga.h forcibly, let vt_buffer.h do it.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
---
 drivers/video/console/mdacon.c | 1 -
 include/linux/vt_buffer.h      | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index ef29b321967f..5898d01bc492 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -42,7 +42,6 @@
 #include <linux/init.h>
 
 #include <asm/io.h>
-#include <asm/vga.h>
 
 static DEFINE_SPINLOCK(mda_lock);
 
diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h
index 848db1b1569f..3e71f879e7c0 100644
--- a/include/linux/vt_buffer.h
+++ b/include/linux/vt_buffer.h
@@ -16,7 +16,7 @@
 
 #include <linux/string.h>
 
-#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
+#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE) || defined(CONFIG_MDA_CONSOLE_MODULE)
 #include <asm/vga.h>
 #endif
 
-- 
2.25.1

Re: [PATCH] mdacon: fix redefinition of 'scr_memsetw'

[Greg KH]

On Mon, Sep 06, 2021 at 06:20:30PM +0800, Jackie Liu wrote:
> From: Jackie Liu <liuyun01@kylinos.cn>
> 
> CONFIG_VGA_CONSOLE=n and CONFIG_MDA_CONSOLE=n will cause vt_buffer.h not
> include <asm/vga.h>.
> 
> But if we set CONFIG_MDA_CONSOLE=m, mdacon.c include <linux/vt_buffer.h>
> is in front of include <asm/vga.h>. VT_BUF_HAVE_MEMSETW is not defined,
> so vt_buffer.h will define a scr_memsetw, after that, vga.h also define
> a scr_memsetw, so the repeated definition of scr_memsetw appears, builds
> error.
> 
> We only need to make vt_buffer.h also contain vga.h when
> CONFIG_MDA_CONSOLE=m. This problem can be fixed.
> 
> BTW, mdacon.c no need to include vga.h forcibly, let vt_buffer.h do it.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

As this has always been an issue, how is this really a "fix"?

How can the above config options be set in this manner, do you have to
do it manually or does a system really need that configuration?


> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-fbdev@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> ---
>  drivers/video/console/mdacon.c | 1 -
>  include/linux/vt_buffer.h      | 2 +-
>  2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
> index ef29b321967f..5898d01bc492 100644
> --- a/drivers/video/console/mdacon.c
> +++ b/drivers/video/console/mdacon.c
> @@ -42,7 +42,6 @@
>  #include <linux/init.h>
>  
>  #include <asm/io.h>
> -#include <asm/vga.h>
>  
>  static DEFINE_SPINLOCK(mda_lock);
>  
> diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h
> index 848db1b1569f..3e71f879e7c0 100644
> --- a/include/linux/vt_buffer.h
> +++ b/include/linux/vt_buffer.h
> @@ -16,7 +16,7 @@
>  
>  #include <linux/string.h>
>  
> -#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
> +#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE) || defined(CONFIG_MDA_CONSOLE_MODULE)

If this really is needed, please use the correct define macro that
catches both of these options.

thanks,

greg k-h

Re: [PATCH] mdacon: fix redefinition of 'scr_memsetw'

[Jackie Liu]

Hi, Greg.


September 6, 2021 6:46 PM, "Greg KH" <gregkh@linuxfoundation.org> 写到:

> On Mon, Sep 06, 2021 at 06:20:30PM +0800, Jackie Liu wrote:
> 
>> From: Jackie Liu <liuyun01@kylinos.cn>
>> 
>> CONFIG_VGA_CONSOLE=n and CONFIG_MDA_CONSOLE=n will cause vt_buffer.h not
>> include <asm/vga.h>.
>> 
>> But if we set CONFIG_MDA_CONSOLE=m, mdacon.c include <linux/vt_buffer.h>
>> is in front of include <asm/vga.h>. VT_BUF_HAVE_MEMSETW is not defined,
>> so vt_buffer.h will define a scr_memsetw, after that, vga.h also define
>> a scr_memsetw, so the repeated definition of scr_memsetw appears, builds
>> error.
>> 
>> We only need to make vt_buffer.h also contain vga.h when
>> CONFIG_MDA_CONSOLE=m. This problem can be fixed.
>> 
>> BTW, mdacon.c no need to include vga.h forcibly, let vt_buffer.h do it.
>> 
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> 
> As this has always been an issue, how is this really a "fix"?

The problem has always existed, but there will be no compilation errors.
The driver needs to include <asm/vga.h> at the beginning if we want build
CONFIG_MDA_CONSOLE=m

After ac036f9570a2, redefined 'scr_memsetw'. but they are not arm and x86 architectures,
so it's not very important. It can also be Fixes: ac036f9570a2 ("vga: optimise console scrolling")

> 
> How can the above config options be set in this manner, do you have to
> do it manually or does a system really need that configuration?

This is a problem reported by my CI, when doing make randomconfigs. Of course,
this is a very tiny fix.

> 
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: linux-fbdev@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
>> ---
>> drivers/video/console/mdacon.c | 1 -
>> include/linux/vt_buffer.h | 2 +-
>> 2 files changed, 1 insertion(+), 2 deletions(-)
>> 
>> diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
>> index ef29b321967f..5898d01bc492 100644
>> --- a/drivers/video/console/mdacon.c
>> +++ b/drivers/video/console/mdacon.c
>> @@ -42,7 +42,6 @@
>> #include <linux/init.h>
>> 
>> #include <asm/io.h>
>> -#include <asm/vga.h>
>> 
>> static DEFINE_SPINLOCK(mda_lock);
>> 
>> diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h
>> index 848db1b1569f..3e71f879e7c0 100644
>> --- a/include/linux/vt_buffer.h
>> +++ b/include/linux/vt_buffer.h
>> @@ -16,7 +16,7 @@
>> 
>> #include <linux/string.h>
>> 
>> -#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
>> +#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE) ||
>> defined(CONFIG_MDA_CONSOLE_MODULE)
> 
> If this really is needed, please use the correct define macro that
> catches both of these options.

Do you have any suggestions? 

I saw that this file is also written like this：
./arch/arm/mach-pxa/spitz.c:455:#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)

> 
> thanks,
> 
> greg k-h

Best Regards.
Jackie Liu

Re: [PATCH] mdacon: fix redefinition of 'scr_memsetw'

[Greg KH]

On Mon, Sep 06, 2021 at 01:44:21PM +0000, Jackie Liu wrote:
> Hi, Greg.
> 
> 
> September 6, 2021 6:46 PM, "Greg KH" <gregkh@linuxfoundation.org> 写到:
> 
> > On Mon, Sep 06, 2021 at 06:20:30PM +0800, Jackie Liu wrote:
> > 
> >> From: Jackie Liu <liuyun01@kylinos.cn>
> >> 
> >> CONFIG_VGA_CONSOLE=n and CONFIG_MDA_CONSOLE=n will cause vt_buffer.h not
> >> include <asm/vga.h>.
> >> 
> >> But if we set CONFIG_MDA_CONSOLE=m, mdacon.c include <linux/vt_buffer.h>
> >> is in front of include <asm/vga.h>. VT_BUF_HAVE_MEMSETW is not defined,
> >> so vt_buffer.h will define a scr_memsetw, after that, vga.h also define
> >> a scr_memsetw, so the repeated definition of scr_memsetw appears, builds
> >> error.
> >> 
> >> We only need to make vt_buffer.h also contain vga.h when
> >> CONFIG_MDA_CONSOLE=m. This problem can be fixed.
> >> 
> >> BTW, mdacon.c no need to include vga.h forcibly, let vt_buffer.h do it.
> >> 
> >> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > 
> > As this has always been an issue, how is this really a "fix"?
> 
> The problem has always existed, but there will be no compilation errors.
> The driver needs to include <asm/vga.h> at the beginning if we want build
> CONFIG_MDA_CONSOLE=m
> 
> After ac036f9570a2, redefined 'scr_memsetw'. but they are not arm and x86 architectures,
> so it's not very important. It can also be Fixes: ac036f9570a2 ("vga: optimise console scrolling")

That might make more sense to put here, instead of the "beginning of
history".

> > How can the above config options be set in this manner, do you have to
> > do it manually or does a system really need that configuration?
> 
> This is a problem reported by my CI, when doing make randomconfigs. Of course,
> this is a very tiny fix.
> 
> > 
> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> Cc: linux-fbdev@vger.kernel.org
> >> Cc: linux-kernel@vger.kernel.org
> >> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> >> ---
> >> drivers/video/console/mdacon.c | 1 -
> >> include/linux/vt_buffer.h | 2 +-
> >> 2 files changed, 1 insertion(+), 2 deletions(-)
> >> 
> >> diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
> >> index ef29b321967f..5898d01bc492 100644
> >> --- a/drivers/video/console/mdacon.c
> >> +++ b/drivers/video/console/mdacon.c
> >> @@ -42,7 +42,6 @@
> >> #include <linux/init.h>
> >> 
> >> #include <asm/io.h>
> >> -#include <asm/vga.h>
> >> 
> >> static DEFINE_SPINLOCK(mda_lock);
> >> 
> >> diff --git a/include/linux/vt_buffer.h b/include/linux/vt_buffer.h
> >> index 848db1b1569f..3e71f879e7c0 100644
> >> --- a/include/linux/vt_buffer.h
> >> +++ b/include/linux/vt_buffer.h
> >> @@ -16,7 +16,7 @@
> >> 
> >> #include <linux/string.h>
> >> 
> >> -#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
> >> +#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE) ||
> >> defined(CONFIG_MDA_CONSOLE_MODULE)
> > 
> > If this really is needed, please use the correct define macro that
> > catches both of these options.
> 
> Do you have any suggestions? 
> 
> I saw that this file is also written like this：
> ./arch/arm/mach-pxa/spitz.c:455:#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)

Look at the IS_ENABLED() macro.

thanks,

greg k-h