On 06/13/2018 04:37 PM, Mark Jonas wrote:

From: Zhu Yi <redacted>

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 <redacted>
Signed-off-by: Mark Jonas <redacted>
Reviewed-by: Heiko Schocher <redacted>

Applied to linux-can-next.

Marc

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