On Fri, Feb 7, 2020 at 9:02 AM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > On Fri, Feb 07, 2020 at 08:57:39AM -0800, Dan Williams wrote: > > On Wed, Feb 5, 2020 at 11:41 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > > > > On Wed, Feb 05, 2020 at 04:40:44PM -0800, Dan Williams wrote: > > > > > I don't have any reason not to pass phys_addr_t. If that sounds better, > > > > > will make changes. > > > > > > > > The problem is device-mapper. That wants to use offset to route > > > > through the map to the leaf device. If it weren't for the firmware > > > > communication requirement you could do: > > > > > > > > dax_direct_access(...) > > > > generic_dax_zero_page_range(...) > > > > > > > > ...but as long as the firmware error clearing path is required I think > > > > we need to do pass the pgoff through the interface and do the pgoff to > > > > virt / phys translation inside the ops handler. > > > > > > Maybe phys_addr_t was the wrong type - but why do we split the offset > > > into the block device argument into a pgoff and offset into page instead > > > of a single 64-bit value? > > > > Oh, got it yes, that looks odd for sub-page zeroing. Yes, let's just > > have one device relative byte-offset. > > So what's the best type to represent this offset. "u64" or "phys_addr_t" > or "loff_t" or something else. I like phys_addr_t followed by u64. Let's make it u64. phys_addr_t has already led to confusion in this thread because the first question I ask when I read it is "why call ->direct_access() to do the translation when you already have the physical address?".
