Re: [PATCH v4 05/11] cxl: Split out combine_coordinates() for common shared usage

[Dave Jiang <dave.jiang@intel.com>]

On 1/19/24 17:35, Dan Williams wrote:
> Dave Jiang wrote:
>> Refactor the common code of combining coordinates in order to reduce code.
>> Create a new function cxl_cooordinates_combine() it combine two 'struct
>> access_coordinate'.
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>  drivers/cxl/core/cdat.c |   32 +++++++++++++++++++++++---------
>>  drivers/cxl/core/port.c |   18 ++----------------
>>  drivers/cxl/cxl.h       |    4 ++++
>>  3 files changed, 29 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
>> index cd84d87f597a..4d542627d02d 100644
>> --- a/drivers/cxl/core/cdat.c
>> +++ b/drivers/cxl/core/cdat.c
>> @@ -183,15 +183,7 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
>>  	xa_for_each(dsmas_xa, index, dent) {
>>  		int qos_class;
>>  
>> -		dent->coord.read_latency = dent->coord.read_latency +
>> -					   c.read_latency;
>> -		dent->coord.write_latency = dent->coord.write_latency +
>> -					    c.write_latency;
>> -		dent->coord.read_bandwidth = min_t(int, c.read_bandwidth,
>> -						   dent->coord.read_bandwidth);
>> -		dent->coord.write_bandwidth = min_t(int, c.write_bandwidth,
>> -						    dent->coord.write_bandwidth);
>> -
>> +		cxl_coordinates_combine(&dent->coord, &dent->coord, &c);
>>  		dent->entries = 1;
>>  		rc = cxl_root->ops->qos_class(root_port, &dent->coord, 1, &qos_class);
>>  		if (rc != 1)
>> @@ -514,4 +506,26 @@ void cxl_switch_parse_cdat(struct cxl_port *port)
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_switch_parse_cdat, CXL);
>>  
>> +/**
>> + * cxl_coordinates_combine - Combine the two input coordinates into the first
>> + *
>> + * @c1: first coordinate, to be written to
>> + * @c2: second coordinate
>> + */
>> +void cxl_coordinates_combine(struct access_coordinate *out,
>> +			     struct access_coordinate *c1,
>> +			     struct access_coordinate *c2)
>> +{
>> +		if (c2->write_bandwidth)
>> +			out->write_bandwidth = min(c1->write_bandwidth,
>> +						   c2->write_bandwidth);
>> +		out->write_latency = c1->write_latency + c2->write_latency;
>> +
>> +		if (c2->read_bandwidth)
>> +			out->read_bandwidth = min(c1->read_bandwidth,
>> +						  c2->read_bandwidth);
>> +		out->read_latency = c1->read_latency + c2->read_latency;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_coordinates_combine, CXL);
> 
> There is no need for EXPORT_SYMBOL() when the definition and the only
> caller exist within the same compilation unit, cxl_core.o.
> 
> However, given there is nothing "CXL" about this function it likely wants
> to move out of cxl_core.o if another caller ever arrives.

It's mostly used by core/cdat.c but eventually also used by core/port.c. So it's all within the core. 
>