net: dsa: Introduce dsa_is_port_initialized

To avoid race conditions when using the ds->ports[] array,
we need to check if the accessed port has been initialized.
Introduce and use helper function dsa_is_port_initialized
for that purpose and use it where needed.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 92be34791963..c542c131d551 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -165,6 +165,11 @@ static inline bool dsa_is_cpu_port(struct dsa_switch *ds, int p)
         return !!(ds->index == ds->dst->cpu_switch && p == ds->dst->cpu_port);
 }
 
+static inline bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
+{
+        return ds->phys_port_mask & (1 << p) && ds->ports[p];
+}
+
 static inline u8 dsa_upstream_port(struct dsa_switch *ds)
 {
         struct dsa_switch_tree *dst = ds->dst;