Re: [PATCH v13 5/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ

[Pankaj Gupta]

> 
> On 08/03/2017 04:13 PM, Pankaj Gupta wrote:
> >>
> >> +        /* Allocate space for find_vqs parameters */
> >> +        vqs = kcalloc(nvqs, sizeof(*vqs), GFP_KERNEL);
> >> +        if (!vqs)
> >> +                goto err_vq;
> >> +        callbacks = kmalloc_array(nvqs, sizeof(*callbacks), GFP_KERNEL);
> >> +        if (!callbacks)
> >> +                goto err_callback;
> >> +        names = kmalloc_array(nvqs, sizeof(*names), GFP_KERNEL);
> >                      
> >         is size here (integer) intentional?
> 
> 
> Sorry, I didn't get it. Could you please elaborate more?

This is okay

> 
> 
> >
> >> +        if (!names)
> >> +                goto err_names;
> >> +
> >> +        callbacks[0] = balloon_ack;
> >> +        names[0] = "inflate";
> >> +        callbacks[1] = balloon_ack;
> >> +        names[1] = "deflate";
> >> +
> >> +        i = 2;
> >> +        if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
> >> +                callbacks[i] = stats_request;
> > just thinking if memory for callbacks[3] & names[3] is allocated?
> 
> 
> Yes, the above kmalloc_array allocated them.

I mean we have created callbacks array for two entries 0,1?

callbacks = kmalloc_array(nvqs, sizeof(*callbacks), GFP_KERNEL);

But we are trying to access location '2' which is third:

         i = 2;
+        if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
+                callbacks[i] = stats_request;      <---- callbacks[2]
+                names[i] = "stats";                <----- names[2]
+                i++;
+        }

I am missing anything obvious here?

> 
> 
> Best,
> Wei
>