On 06/10/2010 06:02 PM, Catalin Marinas wrote: > The data in the cmd_block buffers may reach the main memory after the > writel() to the device ports. This patch introduces two calls to wmb() > to ensure the relative ordering. > > Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> > Tested-by: Colin Tuckley <colin.tuckley@xxxxxxx> > Cc: Tejun Heo <tj@xxxxxxxxxx> > Cc: Jeff Garzik <jeff@xxxxxxxxxx> I suppose you have tested and verified that this is actually necessary, right? I've been looking through the docs but couldn't find anything which described the ordering between writes to main memory and write[bwl]()'s. One thing that kind of bothers me is that r/wmb()'s are for ordering memory accesses among CPUs which participate in cache coherency protocol and although it may work right in the above case I'm not really sure whether this is the right thing to do. Do you have more information on the subject? 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
