Re: [PATCH v3 07/14] drm/panthor: Add the MMU/VM logical block

[Boris Brezillon <boris.brezillon@collabora.com>]

On Mon,  4 Dec 2023 18:33:00 +0100
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> +static int panthor_gpuva_sm_step_remap(struct drm_gpuva_op *op,
> +				       void *priv)
> +{
> +	struct panthor_vma *unmap_vma = container_of(op->remap.unmap->va, struct panthor_vma, base);
> +	struct panthor_vm *vm = priv;
> +	struct panthor_vm_op_ctx *op_ctx = vm->op_ctx;
> +	struct drm_gpuva *prev_va = NULL, *next_va = NULL;
> +	u64 unmap_start, unmap_range;
> +	int ret;
> +
> +	drm_gpuva_op_remap_to_unmap_range(&op->remap, &unmap_start, &unmap_range);
> +	ret = panthor_vm_unmap_pages(vm, unmap_start, unmap_range);
> +	if (ret)
> +		return ret;
> +
> +	if (op->remap.prev) {
> +		panthor_vma_init(op_ctx->map.prev_vma, unmap_vma->flags);
> +		prev_va = &op_ctx->map.prev_vma->base;
> +	}
> +
> +	if (op->remap.next) {
> +		panthor_vma_init(op_ctx->map.next_vma, unmap_vma->flags);
> +		next_va = &op_ctx->map.next_vma->base;
> +	}
> +
> +	drm_gpuva_remap(prev_va, next_va, &op->remap);
> +
> +	if (prev_va) {
> +		panthor_vma_link(vm, op_ctx->map.prev_vma, op->remap.unmap->va->vm_bo);

panthor_vma_link() transfers the vm_bo ownership to the vma object, we
need to take a reference if we want to keep vm_bo's refcount balanced.

> +		op_ctx->map.prev_vma = NULL;
> +	}
> +
> +	if (next_va) {
> +		panthor_vma_link(vm, op_ctx->map.next_vma, op->remap.unmap->va->vm_bo);
> +		op_ctx->map.next_vma = NULL;
> +	}
> +
> +	panthor_vma_unlink(vm, unmap_vma);
> +	return 0;
> +}