[Patch] drbd: check MODULE for THIS_MODULE

[Patch] drbd: check MODULE for THIS_MODULE

[Cong Wang]

THIS_MODULE is NULL only when drbd is compiled as built-in,
so the #ifdef CONFIG_MODULES should be #ifdef MODULE instead.

This fixes the warning:

drivers/block/drbd/drbd_main.c: In function ‘drbd_buildtag’:
drivers/block/drbd/drbd_main.c:4187:24: warning: the comparison will always evaluate as ‘true’ for the address of ‘__this_module’ will never be NULL [-Waddress]

Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>

---
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 211fc44..96c432f 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -4183,12 +4183,11 @@ const char *drbd_buildtag(void)
 	static char buildtag[38] = "\0uilt-in";
 
 	if (buildtag[0] == 0) {
-#ifdef CONFIG_MODULES
-		if (THIS_MODULE != NULL)
-			sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
-		else
+#ifdef MODULE
+		sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
+#else
+		buildtag[0] = 'b';
 #endif
-			buildtag[0] = 'b';
 	}
 
 	return buildtag;

Re: [Patch] drbd: check MODULE for THIS_MODULE

[Andrew Morton]

On Tue,  3 Apr 2012 14:13:36 +0800
Cong Wang <xiyou.wangcong@gmail.com> wrote:

> THIS_MODULE is NULL only when drbd is compiled as built-in,
> so the #ifdef CONFIG_MODULES should be #ifdef MODULE instead.
> 
> This fixes the warning:
> 
> drivers/block/drbd/drbd_main.c: In function ___drbd_buildtag___:
> drivers/block/drbd/drbd_main.c:4187:24: warning: the comparison will always evaluate as ___true___ for the address of _____this_module___ will never be NULL [-Waddress]
> 
> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
> 
> ---
> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> index 211fc44..96c432f 100644
> --- a/drivers/block/drbd/drbd_main.c
> +++ b/drivers/block/drbd/drbd_main.c
> @@ -4183,12 +4183,11 @@ const char *drbd_buildtag(void)
>  	static char buildtag[38] = "\0uilt-in";
>  
>  	if (buildtag[0] == 0) {
> -#ifdef CONFIG_MODULES
> -		if (THIS_MODULE != NULL)
> -			sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
> -		else
> +#ifdef MODULE
> +		sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
> +#else
> +		buildtag[0] = 'b';
>  #endif
> -			buildtag[0] = 'b';
>  	}
>  
>  	return buildtag;

If the MODULE_SRCVERSION_ALL help in init/Kconfig is to be believed,
this should depend on CONFIG_MODULE_SRCVERSION_ALL?

But drbd is the only driver in all of Linux which plays with
srcversion.  Can we just delete this code?

Re: [Drbd-dev] [Patch] drbd: check MODULE for THIS_MODULE

[Lars Ellenberg]

On Mon, Apr 09, 2012 at 04:14:27PM -0700, Andrew Morton wrote:
> On Tue,  3 Apr 2012 14:13:36 +0800
> Cong Wang <xiyou.wangcong@gmail.com> wrote:
> 
> > THIS_MODULE is NULL only when drbd is compiled as built-in,
> > so the #ifdef CONFIG_MODULES should be #ifdef MODULE instead.
> > 
> > This fixes the warning:
> > 
> > drivers/block/drbd/drbd_main.c: In function ___drbd_buildtag___:
> > drivers/block/drbd/drbd_main.c:4187:24: warning: the comparison will always evaluate as ___true___ for the address of _____this_module___ will never be NULL [-Waddress]
> > 
> > Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
> > Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
> > 
> > ---
> > diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> > index 211fc44..96c432f 100644
> > --- a/drivers/block/drbd/drbd_main.c
> > +++ b/drivers/block/drbd/drbd_main.c
> > @@ -4183,12 +4183,11 @@ const char *drbd_buildtag(void)
> >  	static char buildtag[38] = "\0uilt-in";
> >  
> >  	if (buildtag[0] == 0) {
> > -#ifdef CONFIG_MODULES
> > -		if (THIS_MODULE != NULL)
> > -			sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
> > -		else
> > +#ifdef MODULE
> > +		sprintf(buildtag, "srcversion: %-24s", THIS_MODULE->srcversion);
> > +#else
> > +		buildtag[0] = 'b';
> >  #endif
> > -			buildtag[0] = 'b';
> >  	}
> >  
> >  	return buildtag;
> 
> If the MODULE_SRCVERSION_ALL help in init/Kconfig is to be believed,
> this should depend on CONFIG_MODULE_SRCVERSION_ALL?
> 
> But drbd is the only driver in all of Linux which plays with
> srcversion.  Can we just delete this code?

Technically we sure can.

cat /proc/drbd is the first thing we ask for in problem reports, and it
sure helps and saves a few roundtrips knowing which exact version of
in-tree or out-of-tree drbd version is in use.
For an out-of-tree build, we print the exact git-hash there.
For an in-tree build, the srcversion was the "obvious" substitute.
If it is not too much trouble, I'd like to keep that info.

	Lars