mm: use passed vm_fault structure for in wp_pfn_shared()

Instead of creating another vm_fault structure, use the one passed to
wp_pfn_shared() for passing arguments into pfn_mkwrite handler.

Link: http://lkml.kernel.org/r/1479460644-25076-7-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -2273,16 +2273,11 @@ static int wp_pfn_shared(struct vm_fault *vmf, pte_t orig_pte)
 	struct vm_area_struct *vma = vmf->vma;
 
 	if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
-		struct vm_fault vmf2 = {
-			.page = NULL,
-			.pgoff = vmf->pgoff,
-			.address = vmf->address,
-			.flags = FAULT_FLAG_WRITE | FAULT_FLAG_MKWRITE,
-		};
 		int ret;
 
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
-		ret = vma->vm_ops->pfn_mkwrite(vma, &vmf2);
+		vmf->flags |= FAULT_FLAG_MKWRITE;
+		ret = vma->vm_ops->pfn_mkwrite(vma, vmf);
 		if (ret & VM_FAULT_ERROR)
 			return ret;
 		vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,