[PATCH 1/2] lmb: Fix lmb property's defination under struct lmb

Heinrich Schuchardt xypron.glpk at gmx.de
Tue Jan 18 17:17:35 CET 2022


On 1/17/22 17:23, Patrick DELAUNAY wrote:
> Hi,
>
> On 1/14/22 1:14 PM, Michal Simek wrote:
>> From: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
>>
>> Under struct lmb {} the lmb property's should be defined only if
>> CONFIG_LMB_MEMORY_REGIONS is defined.
>>
>> Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>> ---
>>
>>   include/lmb.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/lmb.h b/include/lmb.h
>> index ab277ca80004..1476d78c2823 100644
>> --- a/include/lmb.h
>> +++ b/include/lmb.h
>> @@ -68,7 +68,7 @@ struct lmb_region {
>>   struct lmb {
>>       struct lmb_region memory;
>>       struct lmb_region reserved;
>> -#if !IS_ENABLED(CONFIG_LMB_USE_MAX_REGIONS)
>> +#if IS_ENABLED(CONFIG_LMB_MEMORY_REGIONS)
>>       struct lmb_property memory_regions[CONFIG_LMB_MEMORY_REGIONS];
>>       struct lmb_property reserved_regions[CONFIG_LMB_RESERVED_REGIONS];
>>   #endif
>
>
> I think this patch don't change the exiting code
>
> because in lib/Kconfig we have also the dependancy with
> LMB_USE_MAX_REGIONS:
>
>    config LMB_MEMORY_REGIONS
>        int "Number of memory regions in lmb lib"
>        depends on LMB && !LMB_USE_MAX_REGIONS
>
> => memory_regions and reserved_regions are needed in struc lmb
>     only if CONFIG_LMB_USE_MAX_REGIONS is not defined
>     else it is defined in "struct lmb_region" under the SAME compilation
> flag
>
>
> struct lmb_region {
>      unsigned long cnt;
>      unsigned long max;
> #if IS_ENABLED(CONFIG_LMB_USE_MAX_REGIONS)
>      struct lmb_property region[CONFIG_LMB_MAX_REGIONS];
> #else
>      struct lmb_property *region;
> #endif
> };
>
> with .region = pointer to 'memory_regions[]' or 'reserved_regions[]' in
> "struct lmb"
>
> I think it is more clear to have the compilation flag in "struct
> lmb_region" and in "struct lmb_region".
>
> but I have no objection to change it.
>
>
> PS: I introduce this flag to keep the previous behavior and previous
> struct size on other platform
>
>        when I push the commit 6d66502bc741 ("lmb: Add 2 config to define
> the max number of regions")
>
> Regards
>
> Patrick
>
>

Should we really use #ifdef for these structures to save some bytes on
the stack. Isn't it preferable to move the code from using '#ifdef
CONFIG' to 'if IS_ENABLED(CONFIG'?

Best regards

Heinrich



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