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

[Sergey Shtylyov <s.shtylyov@omp.ru>]

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?

> +		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