Re: [dpdk-dev] [PATCH v2 4/4] lib: reduce global variable usage

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/8/2018 9:45 AM, Shreyansh Jain wrote:
> On Friday 05 October 2018 09:56 PM, Ferruh Yigit wrote:
>> Some global variables can be eliminated, since they are not part of
>> public interface, it is free to remove them.
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>> ---
>>   lib/librte_compressdev/rte_compressdev.c     | 32 ++++++++----------
>>   lib/librte_compressdev/rte_compressdev_pmd.h |  5 ---
>>   lib/librte_cryptodev/rte_cryptodev.c         | 34 +++++++++-----------
>>   lib/librte_cryptodev/rte_cryptodev_pmd.h     |  3 --
>>   lib/librte_eventdev/rte_eventdev.c           |  8 ++---
>>   lib/librte_eventdev/rte_eventdev_pmd.h       |  2 --
>>   lib/librte_rawdev/rte_rawdev.c               | 10 +++---
>>   lib/librte_rawdev/rte_rawdev_pmd.h           |  2 --
>>   8 files changed, 37 insertions(+), 59 deletions(-)
> 
> [...]
> 
>> diff --git a/lib/librte_rawdev/rte_rawdev.c b/lib/librte_rawdev/rte_rawdev.c
>> index 62b6b97ef..9f1e3592d 100644
>> --- a/lib/librte_rawdev/rte_rawdev.c
>> +++ b/lib/librte_rawdev/rte_rawdev.c
>> @@ -35,21 +35,19 @@
>>   /* dynamic log identifier */
>>   int librawdev_logtype;
>>   
>> -struct rte_rawdev rte_rawdevices[RTE_RAWDEV_MAX_DEVS];
>> +static struct rte_rawdev rte_rawdevices[RTE_RAWDEV_MAX_DEVS];
>>   
>> -struct rte_rawdev *rte_rawdevs = &rte_rawdevices[0];
>> +struct rte_rawdev *rte_rawdevs = rte_rawdevices;
>>   
>>   static struct rte_rawdev_global rawdev_globals = {
>>   	.nb_devs		= 0
>>   };
>>   
>> -struct rte_rawdev_global *rte_rawdev_globals = &rawdev_globals;
>> -
>>   /* Raw device, northbound API implementation */
>>   uint8_t
>>   rte_rawdev_count(void)
>>   {
>> -	return rte_rawdev_globals->nb_devs;
>> +	return rawdev_globals.nb_devs;
>>   }
>>   
>>   uint16_t
>> @@ -60,7 +58,7 @@ rte_rawdev_get_dev_id(const char *name)
>>   	if (!name)
>>   		return -EINVAL;
>>   
>> -	for (i = 0; i < rte_rawdev_globals->nb_devs; i++)
>> +	for (i = 0; i < rawdev_globals.nb_devs; i++)
>>   		if ((strcmp(rte_rawdevices[i].name, name)
>>   				== 0) &&
>>   				(rte_rawdevices[i].attached ==
>> diff --git a/lib/librte_rawdev/rte_rawdev_pmd.h b/lib/librte_rawdev/rte_rawdev_pmd.h
>> index bb9bbc350..811e51d07 100644
>> --- a/lib/librte_rawdev/rte_rawdev_pmd.h
>> +++ b/lib/librte_rawdev/rte_rawdev_pmd.h
>> @@ -73,8 +73,6 @@ struct rte_rawdev_global {
>>   	uint16_t nb_devs;
>>   };
>>   
>> -extern struct rte_rawdev_global *rte_rawdev_globals;
>> -/** Pointer to global raw devices data structure. */
>>   extern struct rte_rawdev *rte_rawdevs;
>>   /** The pool of rte_rawdev structures. */
> 
> I think `rte_rawdevs` can also be removed from an exposed symbol. In all 
> cases (at least for now), this is being accessed using an API (and no 
> macros). There should be no need for people to read this directly if 
> sufficient get_by_* APIs are available.

+1 to make it library internal.

But `rte_rawdevs` is both in public header and .map file, so it is part of
public API, we can't remove it without deprecation process.
And I want to leave the decision of removing an public symbol to library
maintainers.

> 
> Wouldn't same be valid for rte_compressdevs as well?

`rte_compressdevs` is already removed, but if you mean `rte_cryptodevs` it has
same problem with `rte_rawdevs`, it is part of API.

> Besides the above:
> 
> Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>
>