From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH 2/6] Provide a mechanism to register domain
 owner of a PCI device.
Date: Wed, 09 Dec 2009 15:33:40 -0800
Message-ID: <4B2033D4.5020700@goop.org>
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	<1260398597-11468-1-git-send-email-konrad.wilk@oracle.com>
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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On 12/09/09 14:43, Konrad Rzeszutek Wilk wrote:
> . and also to find the domain owner based on the PCI device and
> to unregister a domain owner of a PCI device.
>    
Could you fix this up a bit?

> +int xen_register_device_domain_owner(struct pci_dev *dev, domid_t domain)
> +{
> +	struct xen_device_domain_owner *owner;
> +	unsigned long flags;
> +	int rc = 0;
> +
> +	spin_lock_irqsave(&dev_domain_list_spinlock, flags);
>    
Are you expecting interrupt routines could also hold the lock?

> +	if (find_device(dev)) {
> +		rc = -EEXIST;
> +		goto out;
> +	}
> +	owner = kzalloc(sizeof(struct xen_device_domain_owner), GFP_KERNEL);
>    

This can block, so you can't do it while holding the lock.  Its probably 
best to allocate it first on the assumption that it will be used (it 
seems probable that duplicate registrations are at least unlikely, and 
possibly a bug).

Thanks,
     J