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can: dev: enable multi-queue for SocketCAN devices 

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>
hifive-unleashed-5.1
Zhu Yi 2018-06-13 16:37:17 +02:00 committed by Marc Kleine-Budde
parent 8551e71d10
commit 0387090713
2 changed files with 11 additions and 4 deletions
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8
drivers/net/can/dev.c
View File

@ -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

7
include/linux/can/dev.h
View File

@ -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 */