[PATCH v3 09/17] memblock: make memblock_debug and related functionality private

[Mike Rapoport]

On Wed, Aug 19, 2020 at 12:24:05PM -0700, Andrew Morton wrote:
> On Tue, 18 Aug 2020 18:16:26 +0300 Mike Rapoport <rppt at kernel.org> wrote:
> 
> > From: Mike Rapoport <rppt at linux.ibm.com>
> > 
> > The only user of memblock_dbg() outside memblock was s390 setup code and it
> > is converted to use pr_debug() instead.
> > This allows to stop exposing memblock_debug and memblock_dbg() to the rest
> > of the kernel.
> > 
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -137,7 +137,10 @@ struct memblock_type physmem = {
> >  	     i < memblock_type->cnt;					\
> >  	     i++, rgn = &memblock_type->regions[i])
> >  
> > -int memblock_debug __initdata_memblock;
> > +#define memblock_dbg(fmt, ...) \
> > +	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> > +
> 
> checkpatch doesn't like this much.
> 
> ERROR: Macros starting with if should be enclosed by a do - while loop to avoid possible if/else logic defects
> #101: FILE: mm/memblock.c:140:
> +#define memblock_dbg(fmt, ...) \
> +	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> 
> WARNING: Prefer [subsystem eg: netdev]_info([subsystem]dev, ... then dev_info(dev, ... then pr_info(...  to printk(KERN_INFO ...
> #102: FILE: mm/memblock.c:141:
> +	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> 
> ERROR: trailing statements should be on next line
> #102: FILE: mm/memblock.c:141:
> +	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> 
> 
> The first one is significant:
> 
> 	if (foo)
> 		memblock_dbg(...);
> 	else
> 		save_the_world();
> 
> could end up inadvertently destroying the planet.

Well, it didn't till now ;-)

> This?
> 
> --- a/mm/memblock.c~memblock-make-memblock_debug-and-related-functionality-private-fix
> +++ a/mm/memblock.c
> @@ -137,8 +137,11 @@ struct memblock_type physmem = {
>  	     i < memblock_type->cnt;					\
>  	     i++, rgn = &memblock_type->regions[i])
>  
> -#define memblock_dbg(fmt, ...) \
> -	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> +#define memblock_dbg(fmt, ...)						\
> +	do {								\
> +		if (memblock_debug)					\
> +			pr_info(fmt, ##__VA_ARGS__);			\
> +	} while (0)

Sure, thanks!

>  static int memblock_debug __initdata_memblock;
>  static bool system_has_some_mirror __initdata_memblock = false;
> _
> 

-- 
Sincerely yours,
Mike.