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mlxsw will use NAPI for event processing in a next patch. As preparation, add two dummy net devices and initialize them. NAPI instance should be attached to net device. Usually each queue is used by a single net device in network drivers, so the mapping between net device to NAPI instance is intuitive. In our case, Rx queues are not per port, they are per trap-group. Tx queues are mapped to net devices, but we do not have a separate queue for each local port, several ports share the same queue. Use init_dummy_netdev() to initialize dummy net devices for NAPI. To run NAPI poll method in a kernel thread, the net device which NAPI instance is attached to should be marked as 'threaded'. It is recommended to handle Tx packets in softIRQ context, as usually this is a short task - just free the Tx packet which has been transmitted. Rx packets handling is more complicated task, so drivers can use a dedicated kernel thread to process them. It allows processing packets from different Rx queues in parallel. We would like to handle only Rx packets in kernel threads, which means that we will use two dummy net devices (one for Rx and one for Tx). Set only one of them with 'threaded' as it will be used for Rx processing. Do not fail in case that setting 'threaded' fails, as it is better to use regular softIRQ NAPI rather than preventing the driver from loading. Note that the net devices are initialized with init_dummy_netdev(), so they are not registered, which means that they will not be visible to user. It will not be possible to change 'threaded' configuration from user space, but it is reasonable in our case, as there is no another configuration which makes sense, considering that user has no influence on the usage of each queue. Signed-off-by: Amit Cohen <amcohen@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Signed-off-by: Petr Machata <petrm@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.