Re: [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  wrote:
> 
> > From: Mike Rapoport 
> > 
> > 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 = _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 = _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.

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

[Andrew Morton]

On Tue, 18 Aug 2020 18:16:26 +0300 Mike Rapoport  wrote:

> From: Mike Rapoport 
> 
> 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 = _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.

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