On Thu, Apr 25, 2019 at 12:32 AM Jan Kara jack@suse.cz wrote:
On Wed 24-04-19 11:13:48, Dan Williams wrote:
On Wed, Apr 24, 2019 at 10:38 AM Matthew Wilcox willy@infradead.org wrote:
On Wed, Apr 24, 2019 at 10:13:15AM -0700, Dan Williams wrote:
I think unaligned addresses have always been passed to vmf_insert_pfn_pmd(), but nothing cared until this patch. I *think* the only change needed is the following, thoughts?
diff --git a/fs/dax.c b/fs/dax.c index ca0671d55aa6..82aee9a87efa 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1560,7 +1560,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, }
trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry);
result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn,
result = vmf_insert_pfn_pmd(vma, pmd_addr, vmf->pmd, pfn, write);We also call vmf_insert_pfn_pmd() in dax_insert_pfn_mkwrite() -- does that need to change too?
It wasn't clear to me that it was a problem. I think that one already happens to be pmd-aligned.
Why would it need to be? The address is taken from vmf->address and that's set up in __handle_mm_fault() like .address = address & PAGE_MASK. So I don't see anything forcing PMD alignment of the virtual address...
True. So now I'm wondering if the masking should be done internal to the routine. Given it's prefixed vmf_ it seems to imply the api is prepared to take raw 'struct vm_fault' parameters. I think I'll go that route unless someone sees a reason to require the caller to handle this responsibility.