On Wed, May 20, 2015 at 07:00:25AM -0500, Suravee Suthikulanit wrote:
On 5/20/2015 4:34 AM, Catalin Marinas wrote:
We have a dummy of_dma_configure() already when !CONFIG_OF, otherwise we would need #ifndef here. I already replied, I think for other architectures we need this check to avoid a useless host->of_node test.
It seems that there are several places that have similar check. Would it be good to convert this into a macro? Something like:
#define OF_NODE_ENABLED(dev) (IS_ENABLED(CONFIG_OF) && dev->of_node)
This /could/ be a useful compile-time optimisation: when CONFIG_OF is disabled, dev->of_node exists but will always be NULL - but the compiler doesn't know this. Your suggestion above would tell the compiler that when CONFIG_OF is disabled, OF_NODE_ENABLED() will evaluate to a constant false, which means it can eliminate code.