Re: [dm-devel] [PATCH]: create sysfs file, dh_state for SCSI devices even if they are not in the inteernal lists

[Hannes Reinecke <hare@xxxxxxx>]

James Bottomley wrote:
> On Mon, 2009-06-29 at 09:40 +0200, Hannes Reinecke wrote:
>> Chandra Seetharaman wrote:
>>> Create the sysfs file, dh_state even if the new SCSI device is not
>>> in the any of the device handler's internal lists.
>>>
>>> Signed-Off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>
>>> ---
>>>  drivers/scsi/device_handler/scsi_dh.c |   11 ++++-------
>>>  1 file changed, 4 insertions(+), 7 deletions(-)
>>>
>>> Index: linux-2.6.31-rc1/drivers/scsi/device_handler/scsi_dh.c
>>> ===================================================================
>>> --- linux-2.6.31-rc1.orig/drivers/scsi/device_handler/scsi_dh.c
>>> +++ linux-2.6.31-rc1/drivers/scsi/device_handler/scsi_dh.c
>>> @@ -304,18 +304,15 @@ static int scsi_dh_notifier(struct notif
>>>  	sdev = to_scsi_device(dev);
>>>  
>>>  	if (action == BUS_NOTIFY_ADD_DEVICE) {
>>> +		err = device_create_file(dev, &scsi_dh_state_attr);
>>> +		/* don't care about err */
>>>  		devinfo = device_handler_match(NULL, sdev);
>>> -		if (!devinfo)
>>> -			goto out;
>>> -
>>> -		err = scsi_dh_handler_attach(sdev, devinfo);
>>> -		if (!err)
>>> -			err = device_create_file(dev, &scsi_dh_state_attr);
>>> +		if (devinfo)
>>> +			err = scsi_dh_handler_attach(sdev, devinfo);
>>>  	} else if (action == BUS_NOTIFY_DEL_DEVICE) {
>>>  		device_remove_file(dev, &scsi_dh_state_attr);
>>>  		scsi_dh_handler_detach(sdev, NULL);
>>>  	}
>>> -out:
>>>  	return err;
>>>  }
>>>  
>>>
>>>
>> NACK.
>>
>> This will create sysfs attributes even if the attach()
>> failed for other reason like a generic error. So we'll end
>> up with device handler attributes and no device handler attached.
>>
>> Not a good idea.
> 
> It strikes me that what is really being reinvented here is driver
> attachment with driver attribute files ...
> 
> Now all of this could be avoided if we had multiple attachment of
> drivers ... 
> 
I heard you.

If you find someone to fix the blasted iSCSI I/O stall for me ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@xxxxxxx			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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