mm: use passed vm_fault structure in __do_fault()

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

Link: http://lkml.kernel.org/r/1479460644-25076-5-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

@@ -2848,37 +2848,31 @@ static int __do_fault(struct vm_fault *vmf, struct page *cow_page,
 		      struct page **page, void **entry)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	struct vm_fault vmf2;
 	int ret;
 
-	vmf2.address = vmf->address;
-	vmf2.pgoff = vmf->pgoff;
-	vmf2.flags = vmf->flags;
-	vmf2.page = NULL;
-	vmf2.gfp_mask = __get_fault_gfp_mask(vma);
-	vmf2.cow_page = cow_page;
+	vmf->cow_page = cow_page;
 
-	ret = vma->vm_ops->fault(vma, &vmf2);
+	ret = vma->vm_ops->fault(vma, vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
 	if (ret & VM_FAULT_DAX_LOCKED) {
-		*entry = vmf2.entry;
+		*entry = vmf->entry;
 		return ret;
 	}
 
-	if (unlikely(PageHWPoison(vmf2.page))) {
+	if (unlikely(PageHWPoison(vmf->page))) {
 		if (ret & VM_FAULT_LOCKED)
-			unlock_page(vmf2.page);
-		put_page(vmf2.page);
+			unlock_page(vmf->page);
+		put_page(vmf->page);
 		return VM_FAULT_HWPOISON;
 	}
 
 	if (unlikely(!(ret & VM_FAULT_LOCKED)))
-		lock_page(vmf2.page);
+		lock_page(vmf->page);
 	else
-		VM_BUG_ON_PAGE(!PageLocked(vmf2.page), vmf2.page);
+		VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page);
 
-	*page = vmf2.page;
+	*page = vmf->page;
 	return ret;
 }
 
@@ -3614,6 +3608,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 		.address = address & PAGE_MASK,
 		.flags = flags,
 		.pgoff = linear_page_index(vma, address),
+		.gfp_mask = __get_fault_gfp_mask(vma),
 	};
 	struct mm_struct *mm = vma->vm_mm;
 	pgd_t *pgd;