Re: [PATCH 2/2] ata: libata-sata: Fix device queue depth control

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 9/24/22 18:49, Sergey Shtylyov wrote:
> Hello!
> 
> On 9/24/22 9:29 AM, Damien Le Moal wrote:
> 
>> The function __ata_change_queue_depth() uses the helper
>> ata_scsi_find_dev() to get the ata_device structure of a scsi device and
>> set that device maximum queue depth. However, when the ata device is
>> managed by libsas, ata_scsi_find_dev() return NULL, turning
> 
>    Returns?
> 
>> __ata_change_queue_depth() into a nop, which prevents the user from
>> setting the maximum queue depth of ATA devices used with libsas based
>> HBAs.
>>
>> Fix this by renaming __ata_change_queue_depth() to
>> ata_change_queue_depth() and adding a pointer to the ata_device
>> structure of the target device as argument. This pointer is provided by
>> ata_scsi_change_queue_depth() using ata_scsi_find_dev() in the case ofi
> 
>    Of?
> 
>> a libata managed device and by sas_change_queue_depth() using
>> sas_to_ata_dev() in the case of a libsas managed ata device.
>>
>> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> [...]
> 
>> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
>> index ff9602a0e54e..c63bb50323c1 100644
>> --- a/drivers/ata/libata-scsi.c
>> +++ b/drivers/ata/libata-scsi.c
>> @@ -1101,6 +1101,11 @@ int ata_scsi_dev_config(struct scsi_device *sdev, struct ata_device *dev)
>>  	if (dev->flags & ATA_DFLAG_AN)
>>  		set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);
>>  
>> +	pr_info("#### can queue %d, ata qd %d, scsi qd %d\n",
> 
>     Hm... isn't this a debugging pr_info() call you forgot to remove?

Oops. Yes. Sending an update. Thanks for the review.

> 
>> +		sdev->host->can_queue,
>> +		ata_id_queue_depth(dev->id),
>> +		sdev->queue_depth);
>> +
>>  	if (dev->flags & ATA_DFLAG_NCQ)
>>  		depth = min(sdev->host->can_queue, ata_id_queue_depth(dev->id));
>>  	depth = min(ATA_MAX_QUEUE, depth);
> [...]
> 
> MBR, Sergey

-- 
Damien Le Moal
Western Digital Research