Re: [PATCH 3/4] scsi: Support scsi_devices without a device wide limit

[John Garry <john.g.garry@oracle.com>]

On 22/04/2026 14:15, Hannes Reinecke wrote:
>> --- a/drivers/scsi/scsi_scan.c
>> +++ b/drivers/scsi/scsi_scan.c
>> @@ -352,18 +352,20 @@ static struct scsi_device 
>> *scsi_alloc_sdev(struct scsi_target *starget,
>>       if (scsi_device_is_pseudo_dev(sdev))
>>           return sdev;
>> -    depth = sdev->host->cmd_per_lun ?: 1;
>> +    if (sdev->host->cmd_per_lun != SCSI_UNLIMITED_CMD_PER_LUN) {
>> +        depth = sdev->host->cmd_per_lun ?: 1;
> Why don't we use a simple flag in the host (or host template) to
> indicate that cmd_per_lun should be ignored?
> I'm not in favour of using magic values for a setting which
> otherwise is a limit.
> Look to dev_loss_tmo as a bad example ...

I think it's better to not have a flag and also keep cmd_per_lun, as 
then we need to sanitize one vs the other. As mentioned in the cover 
letter response, cmd_per_lun could be got rid off / reworked.

Personally I also dislike how the scsi budget code checks for a budget 
map being non-NULL (which is for reserved scsi devices, which doesn't 
need a per-sdev budget map).