[PATCH 2/2] drm/i915/gvt: Fix inconsistent locks holding sequence

[Zhenyu Wang]

On 2017.06.20 14:23:22 +0000, Dong, Chuanxiao wrote:
> > > In this case, rb_first() won't be protected by cache_lock for getting the
> > node.  We may still want this to be protected.
> > >
> > 
> > oh, yeah, you're right, might just use for(;;) though.
> 
> Backing to your suggestion, how about change to below:
> 
> mutex_lock(&cache_lock);
> while ((node = rb_first(...))) {
>       dma = rb_entry(node, struct gvt_dma, node);
>       gvt_dma_unmap_iova(vgpu, dma->iova);
>       gfn = dma->gfn;
>       __gvt_cache_remove_entry(vgpu, dma);
>       mutex_unlock(&cache_lock);
>       vfio_unpin_pages(dev, &gfn, 1);
>      mutex_lock(&cache_lock);
> }
> mutex_unlock(&cache_lock);
> 

Not nice, that's why I suggest to use for style.

-- 
Open Source Technology Center, Intel ltd.

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