hdlc_ppp: fix potential null pointer in ppp_cp_event logging

drivers/net/wan/hdlc_ppp.c: In function ‘ppp_cp_event’:
drivers/net/wan/hdlc_ppp.c:353:17: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
  353 |                 netdev_info(dev, "%s down\n", proto_name(pid));
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/wan/hdlc_ppp.c:342:17: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
  342 |                 netdev_info(dev, "%s up\n", proto_name(pid));
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Update proto_name() to return "LCP" by default instead of NULL.
This change silences the compiler without changing existing behavior
and removes the need for the local 'pname' variable in ppp_cp_event.

Suggested-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Link: https://patch.msgid.link/20251013014319.1608706-1-kriish.sharma2006@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/wan/hdlc_ppp.c b/drivers/net/wan/hdlc_ppp.c
index 7496a2e9a28203e4610efc141d2e5fdaac08b35c..159295c4bd6d820ca51bb768a70437b541cb3f1e 100644 (file)
--- a/drivers/net/wan/hdlc_ppp.c
+++ b/drivers/net/wan/hdlc_ppp.c
@@ -126,14 +126,12 @@ static inline struct proto *get_proto(struct net_device *dev, u16 pid)
 static inline const char *proto_name(u16 pid)
 {
        switch (pid) {
-       case PID_LCP:
-               return "LCP";
        case PID_IPCP:
                return "IPCP";
        case PID_IPV6CP:
                return "IPV6CP";
        default:
-               return NULL;
+               return "LCP";
        }
 }