Messages in this thread | | | Date | Thu, 14 Apr 2016 16:47:57 +0900 | Subject | [Question] refcount of DT node | From | Masahiro Yamada <> |
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Hi experts.
My understanding of refcount of DT node is poor. Please help me understand it correctly.
Sorry if I am asking stupid questions.
[1] Does this reference count exist for Overlay? Is a node freed when its refcount becomes zero?
[2] When of_node_put() should be called, or should not be called?
Shouldn't of_node_put() be called when we are still referencing to any of its properties?
For example, cpu_read_enable_method() in arch/arm64/kernel/cpu_ops.c returns a pointer to the property value instead of creating a copy of it.
In this case, of_node_put() should not be called because we are still referencing the DT property (in other words, referencing to the DT node indirectly).
Am I right?
[3] Is the following code correct?
np = of_find_compatible_node(NULL, NULL,"foo-node"); of_node_put(np); ret = of_address_to_resource(np, 0, &res); if (ret) { pr_err("failed to get resource\n"); return ret; }
Actually I wrote the code above, and it was applied.
But, the node is still referenced while of_address_to_resource() is being run.
So the correct code should be as follows?
np = of_find_compatible_node(NULL, NULL,"foo-node"); ret = of_address_to_resource(np, 0, &res); of_node_put(np); if (ret) { pr_err("failed to get resource\n"); return ret; }
-- Best Regards Masahiro Yamada
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