Re: [PATCH 2/2] virtio: fix double free_irq

[Rusty Russell <rusty@rustcorp.com.au>]

On Wed, 22 Jul 2009 01:29:25 am Michael S. Tsirkin wrote:
> -	if (info->vector != VIRTIO_MSI_NO_VECTOR)
> +	if (info->vector != VIRTIO_MSI_NO_VECTOR) {
>  		free_irq(vp_dev->msix_entries[info->vector].vector, vq);
> +		--vp_dev->msix_used_vectors;
> +	}
>

This only works because the only current caller of vp_del_vq is vp_del_vqs, so 
msix_used_vectors will be 0 after all the queues have been freed.

Make up your mind.  Either find_vq allocates and del_vq frees, or it's find_vqs 
and del_vqs.  I suggest the former, and setting the value VIRTIO_MSI_NO_VECTOR  
to indicate it's already freed.  I think with some cleanups, that loop in 
vp_free_vectors might go away, too.

Rusty.