Merge pull request #240 from fromanirh/pci-lookup-device

pci: add and use LookupDevice

pkg/pci/pci.go

@@ -171,6 +171,16 @@ func New(opts ...*option.Option) (*Info, error) {
 	return info, nil
 }
 
+// lookupDevice gets a device from cached data
+func (info *Info) lookupDevice(address string) *Device {
+	for _, dev := range info.Devices {
+		if dev.Address == address {
+			return dev
+		}
+	}
+	return nil
+}
+
 // simple private struct used to encapsulate PCI information in a top-level
 // "pci" YAML/JSON map/object key
 type pciPrinter struct {

pkg/pci/pci_linux.go

@@ -271,9 +271,14 @@ func findPCIProgrammingInterface(
 }
 
 // GetDevice returns a pointer to a Device struct that describes the PCI
-// device at the requested address. If no such device could be found, returns
-// nil
+// device at the requested address. If no such device could be found, returns nil.
 func (info *Info) GetDevice(address string) *Device {
+	// check cached data first
+	if dev := info.lookupDevice(address); dev != nil {
+		return dev
+	}
+
+	// no cached data, let's get the information from system.
 	fp := getDeviceModaliasPath(info.ctx, address)
 	if fp == "" {
 		info.ctx.Warn("error finding modalias info for device %q", address)