Hello, Robert. Robert Hancock wrote: > Tejun Heo wrote: >> >> ioread/iowrite? > > We know the register's always MMIO on this controller, so it's slightly > more optimal to avoid the conditional in there. Yeah, by a small margin but I think the consensus was to use ioread/write no matter what if it's mapped using iomap. I don't think we guarantee iomapped address == mmio address after all. >> I know it's not specific to this change but does mb() really make >> sense here? I don't think we need any barrier here. > > Not sure. Documentation/memory-barriers.txt seems rather unfortunately > vague on whether MMIO writes are strongly ordered with respect to memory > writes. I seem to recall some debate on this a while ago, did it ever > get resolved? I remember that thread too but don't really any definite conclusion. Eh... I hate barriers lying around without exact explanation. :-( Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
