Re: [PATCH] Fix reference counting for failed SCSI devices

Hannes Reinecke
2005-05-25T12:46:34Z

James Bottomley wrote:
> On Wed, 2005-05-25 at 08:50 +0200, Hannes Reinecke wrote:
>>>>+ class_device_put(&sdev->sdev_classdev);
>>>This is unnecessary since the class device is simply occupying a private
>>>area in the scsi_device. As long as its never made visible to the
>>>system, its refcount is irrelevant
>>>
>>It's not. Whenever you try to rmmod the adapter it becomes highly
>>relevant. If it doesn't crash you've at least generated a memleak as the
>>class device is never freed.
>>(And these are quite a few for Wide-SCSI Double-channel adapters ...)
>
> ? Look at the code; you're not doing a put on a pointer to the
> sdev_classdev, you're doing a put on a reference to it.
>
> It's defined in scsi_device.h:
>
> struct scsi_device {
> ...
> struct class_device sdev_classdev;
> ...
> };
>
> so it's contained within the scsi_device. Freeing the scsi_device frees
> the classdev (and the gendev).
>
But does not call the ->release function.

Put it the other way round: does 'rmmod aic7xxx' work for you?
It certainly did _not_ work for aic79xx, hence the fix.

Cheers,

Hannes
--
Dr. Hannes Reinecke hare@suse.de
SuSE Linux AG S390 & zSeries
Maxfeldstraße 5 +49 911 74053 688
90409 Nürnberg http://www.suse.de