On Tue, Dec 04, 2018 at 04:41:34PM +0000, Robin Murphy wrote: > I'd have been inclined to put the default check here, i.e. > > - return 0 > + return dma_addr == DMA_MAPPING_ERROR > > such that the callback retains full precedence and we don't have to deal > with the non-trivial removals immediately if it comes to it. Not that it > makes a vast difference though, so either way, Ok, I've switched it around.