net: dsa: variable number of ports

Change the ports[DSA_MAX_PORTS] array of the dsa_switch structure for a
zero-length array, allocated at the same time as the dsa_switch
structure itself. A dsa_switch_alloc() helper is provided for that.

This commit brings no functional change yet since we pass DSA_MAX_PORTS
as the number of ports for the moment. Future patches can update the DSA
drivers separately to support dynamic number of ports.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 75f5d1f8554b..4b3a44bec5c8 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -666,6 +666,22 @@ out:
 	return err;
 }
 
+struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n)
+{
+	size_t size = sizeof(struct dsa_switch) + n * sizeof(struct dsa_port);
+	struct dsa_switch *ds;
+
+	ds = devm_kzalloc(dev, size, GFP_KERNEL);
+	if (!ds)
+		return NULL;
+
+	ds->dev = dev;
+	ds->num_ports = n;
+
+	return ds;
+}
+EXPORT_SYMBOL_GPL(dsa_switch_alloc);
+
 int dsa_register_switch(struct dsa_switch *ds, struct device *dev)
 {
 	int err;