The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b90ca5cc32f59bb214847c6855959702f00c6801 Mon Sep 17 00:00:00 2001

From: Matthew Wilcox willy@infradead.org Date: Tue, 11 Sep 2018 21:27:44 -0700 Subject: [PATCH] filesystem-dax: Fix use of zero page

Use my_zero_pfn instead of ZERO_PAGE(), and pass the vaddr to it instead of zero so it works on MIPS and s390 who reference the vaddr to select a zero page.

Cc: stable@vger.kernel.org Fixes: 91d25ba8a6b0 ("dax: use common 4k zero page for dax mmap reads") Signed-off-by: Matthew Wilcox willy@infradead.org Reviewed-by: Ross Zwisler ross.zwisler@linux.intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com

diff --git a/fs/dax.c b/fs/dax.c index f32d7125ad0f..b68ce484e1be 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1120,21 +1120,12 @@ static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry, { struct inode *inode = mapping->host; unsigned long vaddr = vmf->address; - vm_fault_t ret = VM_FAULT_NOPAGE; - struct page *zero_page; - pfn_t pfn; - - zero_page = ZERO_PAGE(0); - if (unlikely(!zero_page)) { - ret = VM_FAULT_OOM; - goto out; - } + pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); + vm_fault_t ret;

- pfn = page_to_pfn_t(zero_page); dax_insert_mapping_entry(mapping, vmf, entry, pfn, RADIX_DAX_ZERO_PAGE, false); ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); -out: trace_dax_load_hole(inode, vmf, ret); return ret; }