Re: [question] Panic in dax_writeback_one

[Matthew Wilcox]

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.