[PATCH] rust: drm: mm: Add DRM MM Range Allocator abstraction

[Daniel Almeida]

Hmm, this has an issue

[..]

> 
> +impl<A: AllocInner<T>, T> Drop for MmInner<A, T> {
> +    fn drop(&mut self) {
> +        // SAFETY: If the MmInner is dropped then all nodes are gone (since they hold references),
> +        // so it is safe to tear down the allocator.
> +        unsafe {
> +            bindings::drm_mm_takedown(self.0.get());
> +        }
> +    }
> +}
> +
> 

Where the docs for drm_mm_takedown states:

/**
* drm_mm_takedown - clean up a drm_mm allocator
* @mm: drm_mm allocator to clean up
*
* Note that it is a bug to call this function on an allocator which is not
* clean.
*/
void drm_mm_takedown(struct drm_mm *mm)
{
if (WARN(!drm_mm_clean(mm),
"Memory manager not clean during takedown.\n"))
show_leaks(mm);
}
EXPORT_SYMBOL(drm_mm_takedown);


So perhaps we should remove all nodes before takedown?

This covers the error path, i.e.: something failed somewhere else and the allocator is dirty.

— Daniel