drm/etnaviv: move MMU context ref/unref into map/unmap_gem

This makes it a little more clear that the mapping holds a reference
to the context once the buffer has been successfully mapped into that
context and simplifies the error handling a bit.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Guido Günther <agx@sigxcpu.org>
Acked-by: Guido Günther <agx@sigxcpu.org>

drivers/gpu/drm/etnaviv/etnaviv_gem.c

@@ -294,18 +294,15 @@ struct etnaviv_vram_mapping *etnaviv_gem_mapping_get(
 		list_del(&mapping->obj_node);
 	}
 
-	mapping->context = etnaviv_iommu_context_get(mmu_context);
 	mapping->use = 1;
 
 	ret = etnaviv_iommu_map_gem(mmu_context, etnaviv_obj,
 				    mmu_context->global->memory_base,
 				    mapping, va);
-	if (ret < 0) {
-		etnaviv_iommu_context_put(mmu_context);
+	if (ret < 0)
 		kfree(mapping);
-	} else {
+	else
 		list_add_tail(&mapping->obj_node, &etnaviv_obj->vram_list);
-	}
 
 out:
 	mutex_unlock(&etnaviv_obj->lock);
@@ -498,10 +495,8 @@ void etnaviv_gem_free_object(struct drm_gem_object *obj)
 
 		WARN_ON(mapping->use);
 
-		if (context) {
+		if (context)
 			etnaviv_iommu_unmap_gem(context, mapping);
-			etnaviv_iommu_context_put(context);
-		}
 
 		list_del(&mapping->obj_node);
 		kfree(mapping);

drivers/gpu/drm/etnaviv/etnaviv_mmu.c

@@ -245,6 +245,7 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu_context *context,
 		iova = sg_dma_address(sgt->sgl) - memory_base;
 		if (iova < 0x80000000 - sg_dma_len(sgt->sgl)) {
 			mapping->iova = iova;
+			mapping->context = etnaviv_iommu_context_get(context);
 			list_add_tail(&mapping->mmu_node, &context->mappings);
 			ret = 0;
 			goto unlock;
@@ -271,6 +272,7 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu_context *context,
 		goto unlock;
 	}
 
+	mapping->context = etnaviv_iommu_context_get(context);
 	list_add_tail(&mapping->mmu_node, &context->mappings);
 	context->flush_seq++;
 unlock:
@@ -299,6 +301,7 @@ void etnaviv_iommu_unmap_gem(struct etnaviv_iommu_context *context,
 	list_del(&mapping->mmu_node);
 	context->flush_seq++;
 	mutex_unlock(&context->lock);
+	etnaviv_iommu_context_put(context);
 }
 
 static void etnaviv_iommu_context_free(struct kref *kref)