The current at91_can driver uses NAPI to handle RX'ed CAN frames, the RX IRQ is disabled and a NAPI poll is scheduled. Then in at91_poll_rx() the RX'ed CAN frames are tried to read in order from the device. This approach has 2 drawbacks: - Under high system load it might take too long from the initial RX IRQ to the NAPI poll function to run. This causes RX buffer overflows. - The algorithm to read the CAN frames in order is not bullet proof and may fail under certain use cases/system loads. The rx-offload helper fixes these problems by reading the RX'ed CAN frames in the interrupt handler and adding it to a list sorted by RX timestamp. This list of RX'ed SKBs is then passed to the networking stack via NAPI. Convert the RX path to rx-offload, pass all CAN error frames with can_rx_offload_queue_timestamp(). Link: https://lore.kernel.org/all/20231005-at91_can-rx_offload-v2-27-9987d53600e0@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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 Restructured Text 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.
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