Re: [Xen-devel] [PATCH v4 06/17] xen/arm: ITS: Add virtual ITS driver

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

Hi Ian,

On Fri, Jul 10, 2015 at 7:24 PM, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> On Fri, 2015-07-10 at 13:12 +0530, vijay.kilari@xxxxxxxxx wrote:
>> +/* RB-tree helpers for vits_device attached to a domain */
>
> In the rest of the series I found this used in three places:
>       * On assignment, to insert the device into the tree
>       * On deassignment, to remove it again
>       * In vgic_vcpu_inject_lpi, where the device is looked up and then
>         never used.
>
> I don't see any other use and therefore I don't think this RB tree
> serves any purpose, which is consistent with the design which doesn't
> require this lookup anywhere. Please remove it.
>
> If there is some use of it in some future series (e.g. perhaps the PCI
> one) then please still remove it and add a patch to that series to
> introduce it.
>

You mean for now we will remove RB-tree for managing devices assigned
to domain and introduce RB-tree and do look up when pci-passthrough is
introduced?.

>
>
>> +struct vits_device *vits_find_device(struct rb_root *root, uint32_t devid)
>> +{
>> +    struct rb_node *node = root->rb_node;
>> +
>> +    while ( node )
>> +    {
>> +        struct vits_device *dev;
>> +
>> +        dev = container_of(node, struct vits_device, node);
>> +
>> +        if ( devid < dev->vdevid )
>> +            node = node->rb_left;
>> +        else if ( devid > dev->vdevid )
>> +            node = node->rb_right;
>> +        else
>> +            return dev;
>> +    }
>> +
>> +    return NULL;
>> +}
>> +
>> +int vits_insert_device(struct rb_root *root, struct vits_device *dev)
>> +{
>> +    struct rb_node **new, *parent;
>> +
>> +    new = &root->rb_node;
>> +    parent = NULL;
>> +    while ( *new )
>> +    {
>> +        struct vits_device *this;
>> +
>> +        this  = container_of(*new, struct vits_device, node);
>> +
>> +        parent = *new;
>> +        if ( dev->vdevid < this->vdevid )
>> +            new = &((*new)->rb_left);
>> +        else if ( dev->vdevid > this->vdevid )
>> +            new = &((*new)->rb_right);
>> +        else
>> +            return -EEXIST;
>> +    }
>> +
>> +    rb_link_node(&dev->node, parent, new);
>> +    rb_insert_color(&dev->node, root);
>> +
>> +    return 0;
>> +}
>> +
>> +void vits_remove_device(struct rb_root *root, struct vits_device *dev)
>> +{
>> +    if ( dev )
>> +        rb_erase(&dev->node, root);
>> +}
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>
>

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