On Tue, Apr 17, 2018 at 9:20 PM, Souptick Joarder [off-list ref] wrote:

Use new return type vm_fault_t for fault handler. 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.

Reference id -> 1c8f422059ae ("mm: change return type to
vm_fault_t")

Previously vm_insert_pfn() returns err but driver returns
VM_FAULT_NOPAGE as default. The new function vmf_insert_pfn()
will replace this inefficiency by returning correct VM_FAULT_*
type.

vmf_handle_error is a inline wrapper function which
will convert error number to vm_fault_t type err.

Signed-off-by: Souptick Joarder <redacted>
Reviewed-by: Matthew Wilcox <redacted>

Acked-by: Arnd Bergmann <arnd@arndb.de>