lib.hardware.pci: cleanup previous commits

src/lib/hardware/pci.lua

@@ -186,20 +186,19 @@ end
 
 function map_pci_memory (f)
    local st = assert(f:stat())
-   local mem, err
-   mem, err = f:mmap(nil, st.size, "read, write", "shared", 0)
+   local mem, err = f:mmap(nil, st.size, "read, write", "shared", 0)
    -- mmap() returns EINVAL on Linux >= 4.5 if the device is still
    -- claimed by the kernel driver. We assume that
    -- unbind_device_from_linux() has already been called but it may take
    -- some time for the driver to release the device.
-   if not mem then
+   if not mem and err.INVAL then
       lib.waitfor2("mmap of "..filepath,
                    function ()
                       mem, err = f:mmap(nil, st.size, "read, write", "shared", 0)
-                      assert(not err or err.INVAL)
-                      return mem
+                      return mem ~= nil or not err.INVAL
                    end, 5, 1000000)
    end
+   assert(mem, err)
    return ffi.cast("uint32_t *", mem)
 end