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

[Shreyansh Jain <shreyansh.jain@nxp.com>]

On Monday 08 October 2018 02:41 PM, Ferruh Yigit wrote:
> 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.

Yes, I missed that part :)
I will fix it in next release by sending deprecation in this.

> 
>>
>> 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.

Ah yes, my mistake.
I was thinking about rte_eventdevs and rte_cryptodevs (but, this symbol 
is being used by a crypto/scheduler)

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