Re: [PATCHv4 11/13] call-forwarding: Re-run ss path queries on CFU unset

[Oleg Zhurakivskyy <oleg.zhurakivskyy@intel.com>]

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Hello Denis,

On 04/24/2012 12:28 AM, Denis Kenzior wrote:
>> static void ss_set_query_cf_callback(const struct ofono_error *error, int total,
>>
>>   	set_new_cond_list(cf, cf->query_next, l);
>>
>> +	if (cf->query_next == CALL_FORWARDING_TYPE_UNCONDITIONAL&&
>> +			cf->query_next == cf->query_end) {
>> +		cf->flags |= CALL_FORWARDING_FLAG_CACHED;
>> +		/*
>> +		 * CFU has been disabled, conditionals need to be updated
>> +		 */
>> +		if (is_cfu_enabled(cf) == FALSE)
>> +			cf->query_end = CALL_FORWARDING_TYPE_NOT_REACHABLE;
>
> So a bit of background, the original set + query logic did not mess with
> the CACHED flag.  The assumption was that we're modifying a single
> property.  If the CACHED flag was already set, then the modification was
> queried and the CACHED flag was still valid.  If the CACHED flag was not
> set, then we'd re-query the entire thing anyway.
>
> Now we have a somewhat funny situation where when we clear CFU, we are
> essentially forced into querying everything.  The immediate problem with
> your approach is that we can't return from the method call until all
> settings have been queried.  By convention the core can have only a
> single outstanding call into the driver at a time.  We bend the rules
> somewhat, but in general we need to stick to this rule.  This is why you
> see busy error conditions everywhere.  So likely this needs a specific
> code path ...

OK, thanks, I see. Would it make sense to return the method immediately and then 
to re-query the conditionals? Or, just to wait until anybody needs them?

> Also, there is an optimization we can make here, e.g. if we queried the
> conditional forwarding settings prior to CFU being enabled, then we can
> keep those around.  This is why the TODO item refers to the 'conditional
> cache.'  In the case of CFU being flipped to enabled and then disabled,
> we do not need to query.

Thanks for the help here. Let's go for this approach too.

Regards,
Oleg
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