On 11/19/2020 4:30 PM, Andrew Lunn wrote:

quoted

+static struct dsa_lag *dsa_lag_get(struct dsa_switch_tree *dst,
+				   struct net_device *dev)
+{
+	unsigned long busy = 0;
+	struct dsa_lag *lag;
+	int id;
+
+	list_for_each_entry(lag, &dst->lags, list) {
+		set_bit(lag->id, &busy);
+
+		if (lag->dev == dev) {
+			kref_get(&lag->refcount);
+			return lag;
+		}
+	}
+
+	id = find_first_zero_bit(&busy, BITS_PER_LONG);
+	if (id >= BITS_PER_LONG)
+		return ERR_PTR(-ENOSPC);
+
+	lag = kzalloc(sizeof(*lag), GFP_KERNEL);
+	if (!lag)
+		return ERR_PTR(-ENOMEM);

Hi Tobias

My comment last time was to statically allocated them at probe
time. Worse case scenario is each port is alone in a LAG. Pointless,
but somebody could configure it. In dsa_tree_setup_switches() you can
count the number of ports and then allocate an array, or while setting
up a port, add one more lag to the list of lags.

The allocation is allowed to sleep (have not checked the calling context
of dsa_lag_get() whether this is OK) so what would be the upside of
doing upfront dsa_lag allocation which could be wasteful?
-- 
Florian