On Thu, Mar 11, 2021 at 4:20 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Thu, Mar 11, 2021 at 07:48:25AM +0000, chenjun (AM) wrote: > > static int dax_writeback_one(struct xa_state *xas, struct dax_device > > *dax_dev, struct address_space *mapping, void *entry) > > ----dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE); > > The pfn is returned by the driver. In my case, the pfn does not have > > struct page. so pfn_to_page(pfn) return a wrong address. > > I wasn't involved, but I think the right solution here is simply to > replace page_address(pfn_to_page(pfn)) with pfn_to_virt(pfn). I don't > know why Dan decided to do this in the more complicated way. pfn_to_virt() only works for the direct-map. If pages are not mapped I don't see how pfn_to_virt() is expected to work. The real question Chenjun is why are you writing a new simulator of memory as a block-device vs reusing the pmem driver or brd?
