can: dev: enable multi-queue for SocketCAN devices (03870907) · Commits · 戴 / test

The existing SocketCAN implementation provides alloc_candev() to allocate a CAN device using a single Tx and Rx queue. This can lead to priority inversion in case the single Tx queue is already full with low priority messages and a high priority message needs to be sent while the bus is fully loaded with medium priority messages. This problem can be solved by using the existing multi-queue support of the network subsytem. The commit makes it possible to use multi-queue in the CAN subsystem in the same way it is used in the Ethernet subsystem by adding an alloc_candev_mqs() call and accompanying macros. With this support a CAN device can use multi-queue qdisc (e.g. mqprio) to avoid the aforementioned priority inversion. The exisiting functionality of alloc_candev() is the same as before. CAN devices need to have prioritized multiple hardware queues or are able to abort waiting for arbitration to make sensible use of multi-queues. Signed-off-by:

Zhu Yi <yi.zhu5@cn.bosch.com> Signed-off-by:

Mark Jonas <mark.jonas@de.bosch.com> Reviewed-by:

Heiko Schocher <hs@denx.de> Signed-off-by:

Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/dev.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -701,7 +701,8 @@ EXPORT_SYMBOL_GPL(alloc_can_err_skb);
		/*
		* Allocate and setup space for the CAN network device
		*/
		struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
		struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
		unsigned int txqs, unsigned int rxqs)
		{
		struct net_device *dev;
		struct can_priv *priv;
		@@ -713,7 +714,8 @@ struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
		else
		size = sizeof_priv;

		dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
		dev = alloc_netdev_mqs(size, "can%d", NET_NAME_UNKNOWN, can_setup,
		txqs, rxqs);
		if (!dev)
		return NULL;

		@@ -732,7 +734,7 @@ struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)

		return dev;
		}
		EXPORT_SYMBOL_GPL(alloc_candev);
		EXPORT_SYMBOL_GPL(alloc_candev_mqs);

		/*
		* Free space of the CAN network device

include/linux/can/dev.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -143,7 +143,12 @@ u8 can_dlc2len(u8 can_dlc);
		/* map the sanitized data length to an appropriate data length code */
		u8 can_len2dlc(u8 len);

		struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
		struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
		unsigned int txqs, unsigned int rxqs);
		#define alloc_candev(sizeof_priv, echo_skb_max) \
		alloc_candev_mqs(sizeof_priv, echo_skb_max, 1, 1)
		#define alloc_candev_mq(sizeof_priv, echo_skb_max, count) \
		alloc_candev_mqs(sizeof_priv, echo_skb_max, count, count)
		void free_candev(struct net_device *dev);

		/* a candev safe wrapper around netdev_priv */

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