infiniband: do not make assumptions about counters based on HCA name (#678)

Some users have reported cases of systemd "predictable network interface
naming" apparently also renaming the HCA device. This means we can no
longer make assumptions about which counter(s) should be present based
on the HCA name (i.e., irdma*, mlx5_*). The previous approach was quite
brittle anyway, since there will undoubtedly be other IB / RoCE drivers
in future which implement the hw_counters directory (but not the older
counters directory).

Signed-off-by: Daniel Swarbrick <daniel.swarbrick@gmail.com>
Signed-off-by: Ben Kochie <superq@gmail.com>
Co-authored-by: Ben Kochie <superq@gmail.com>

Author: dswarbrick

sysfs/class_infiniband.go

@@ -280,16 +280,19 @@ func (fs FS) parseInfiniBandPort(name string, port string) (*InfiniBandPort, err
 		return nil, fmt.Errorf("could not parse rate file in %q: %w", portPath, err)
 	}
 
-	// Intel irdma and Broadcom RoCE does not expose /sys/class/infiniband/<device>/ports/<port-num>/counters
-	if !strings.HasPrefix(ibp.Name, "irdma") && !strings.HasPrefix(ibp.Name, "bnxt_re") {
+	// Since the HCA may have been renamed by systemd, we cannot infer the kernel driver used by the
+	// device, and thus do not know what type(s) of counters should be present. Attempt to parse
+	// either / both "counters" (and potentially also "counters_ext"), and "hw_counters", subject
+	// to their availability on the system - irrespective of HCA naming convention.
+	if _, err := os.Stat(filepath.Join(portPath, "counters")); err == nil {
 		counters, err := parseInfiniBandCounters(portPath)
 		if err != nil {
 			return nil, err
 		}
 		ibp.Counters = *counters
 	}
 
-	if strings.HasPrefix(ibp.Name, "irdma") || strings.HasPrefix(ibp.Name, "mlx5_") {
+	if _, err := os.Stat(filepath.Join(portPath, "hw_counters")); err == nil {
 		hwCounters, err := parseInfiniBandHwCounters(portPath)
 		if err != nil {
 			return nil, err