netdevice: move netdev_cap_txqueue for shared usage to header

In order to allow users to invoke netdev_cap_txqueue, it needs to
be moved into netdevice.h header file. While at it, also add kernel
doc header to document the API.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1de9c136b066..e8eeebd49a98 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2279,6 +2279,26 @@ static inline void netdev_reset_queue(struct net_device *dev_queue)
 }
 
 /**
+ * 	netdev_cap_txqueue - check if selected tx queue exceeds device queues
+ * 	@dev: network device
+ * 	@queue_index: given tx queue index
+ *
+ * 	Returns 0 if given tx queue index >= number of device tx queues,
+ * 	otherwise returns the originally passed tx queue index.
+ */
+static inline u16 netdev_cap_txqueue(struct net_device *dev, u16 queue_index)
+{
+	if (unlikely(queue_index >= dev->real_num_tx_queues)) {
+		net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n",
+				     dev->name, queue_index,
+				     dev->real_num_tx_queues);
+		return 0;
+	}
+
+	return queue_index;
+}
+
+/**
  *	netif_running - test if up
  *	@dev: network device
  *