drm/armada: Adding new typedef vm_fault_t

Use new return type vm_fault_t for fault handler in struct
vm_operations_struct. For now, this is just documenting that the
function returns a VM_FAULT value rather than an errno. Once all
instances are converted, vm_fault_t will become a distinct type.

commit 1c8f4220 ("mm: change return type to vm_fault_t")

Previously vm_insert_pfn() returns err which driver mapped into
VM_FAULT_* type. The new function vmf_insert_pfn() will replace this
inefficiency by returning VM_FAULT_* type.
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

drivers/gpu/drm/armada/armada_gem.c

@@ -13,25 +13,14 @@
 #include <drm/armada_drm.h>
 #include "armada_ioctlP.h"
 
-static int armada_gem_vm_fault(struct vm_fault *vmf)
+static vm_fault_t armada_gem_vm_fault(struct vm_fault *vmf)
 {
 	struct drm_gem_object *gobj = vmf->vma->vm_private_data;
 	struct armada_gem_object *obj = drm_to_armada_gem(gobj);
 	unsigned long pfn = obj->phys_addr >> PAGE_SHIFT;
-	int ret;
 
 	pfn += (vmf->address - vmf->vma->vm_start) >> PAGE_SHIFT;
-	ret = vm_insert_pfn(vmf->vma, vmf->address, pfn);
-
-	switch (ret) {
-	case 0:
-	case -EBUSY:
-		return VM_FAULT_NOPAGE;
-	case -ENOMEM:
-		return VM_FAULT_OOM;
-	default:
-		return VM_FAULT_SIGBUS;
-	}
+	return vmf_insert_pfn(vmf->vma, vmf->address, pfn);
 }
 
 const struct vm_operations_struct armada_gem_vm_ops = {