kernel/drivers/net/can/dev.c, branch linux-6.9.y

can: dev: move driver related infrastructure into separate subdir

2021-01-13T08:42:58Z

This patch moves the CAN driver related infrastructure into a separate subdir. It will be split into more files in the coming patches. Reviewed-by: Vincent Mailhol Link: https://lore.kernel.org/r/20210111141930.693847-3-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: rename CAN FD related can_len2dlc and can_dlc2len helpers

2020-11-20T11:05:14Z

The helper functions can_len2dlc and can_dlc2len are only relevant for CAN FD data length code (DLC) conversion. To fit the introduced can_cc_dlc2len for Classical CAN we rename: can_dlc2len -> can_fd_dlc2len to get the payload length from the DLC can_len2dlc -> can_fd_len2dlc to get the DLC from the payload length Suggested-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20201110101852.1973-6-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde

can: replace can_dlc as variable/element for payload length

2020-11-20T11:04:12Z

The naming of can_dlc as element of struct can_frame and also as variable name is misleading as it claims to be a 'data length CODE' but in reality it always was a plain data length. With the indroduction of a new 'len' element in struct can_frame we can now remove can_dlc as name and make clear which of the former uses was a plain length (-> 'len') or a data length code (-> 'dlc') value. Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20201120100444.3199-1-socketcan@hartkopp.net [mkl: gs_usb: keep struct gs_host_frame::can_dlc as is] Signed-off-by: Marc Kleine-Budde

can: dev: can_restart(): post buffer from the right context

2020-11-15T17:24:35Z

netif_rx() is meant to be called from interrupt contexts. can_restart() may be called by can_restart_work(), which is called from a worqueue, so it may run in process context. Use netif_rx_ni() instead. Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Co-developed-by: Loris Fauster Signed-off-by: Loris Fauster Signed-off-by: Alejandro Concepcion Rodriguez Link: https://lore.kernel.org/r/4e84162b-fb31-3a73-fa9a-9438b4bd5234@acoro.eu [mkl: use netif_rx_ni() instead of netif_rx_any_context()] Signed-off-by: Marc Kleine-Budde

can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames

2020-11-03T21:30:12Z

The can_get_echo_skb() function returns the number of received bytes to be used for netdev statistics. In the case of RTR frames we get a valid (potential non-zero) data length value which has to be passed for further operations. But on the wire RTR frames have no payload length. Therefore the value to be used in the statistics has to be zero for RTR frames. Reported-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20201020064443.80164-1-socketcan@hartkopp.net Fixes: cf5046b309b3 ("can: dev: let can_get_echo_skb() return dlc of CAN frame") Signed-off-by: Marc Kleine-Budde

can: dev: can_get_echo_skb(): prevent call to kfree_skb() in hard IRQ context

2020-11-03T21:24:19Z

If a driver calls can_get_echo_skb() during a hardware IRQ (which is often, but not always, the case), the 'WARN_ON(in_irq)' in net/core/skbuff.c#skb_release_head_state() might be triggered, under network congestion circumstances, together with the potential risk of a NULL pointer dereference. The root cause of this issue is the call to kfree_skb() instead of dev_kfree_skb_irq() in net/core/dev.c#enqueue_to_backlog(). This patch prevents the skb to be freed within the call to netif_rx() by incrementing its reference count with skb_get(). The skb is finally freed by one of the in-irq-context safe functions: dev_consume_skb_any() or dev_kfree_skb_any(). The "any" version is used because some drivers might call can_get_echo_skb() in a normal context. The reason for this issue to occur is that initially, in the core network stack, loopback skb were not supposed to be received in hardware IRQ context. The CAN stack is an exeption. This bug was previously reported back in 2017 in [1] but the proposed patch never got accepted. While [1] directly modifies net/core/dev.c, we try to propose here a smoother modification local to CAN network stack (the assumption behind is that only CAN devices are affected by this issue). [1] http://lore.kernel.org/r/57a3ffb6-3309-3ad5-5a34-e93c3fe3614d@cetitec.com Signed-off-by: Vincent Mailhol Link: https://lore.kernel.org/r/20201002154219.4887-2-mailhol.vincent@wanadoo.fr Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Signed-off-by: Marc Kleine-Budde

can: dev: add a helper function to calculate the duration of one bit

2020-10-07T21:17:45Z

Rename macro CAN_CALC_SYNC_SEG to CAN_SYNC_SEG and make it available through include/linux/can/dev.h Add an helper function can_bit_time() which returns the duration (in time quanta) of one CAN bit. Rationale for this patch: the sync segment and the bit time are two concepts which are defined in the CAN ISO standard. Device drivers for CAN might need those. Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for additional information. Signed-off-by: Vincent Mailhol Link: https://lore.kernel.org/r/20201002154219.4887-6-mailhol.vincent@wanadoo.fr [mkl: Let can_bit_time() return an unsinged int, make argument const] Signed-off-by: Marc Kleine-Budde

can: dev: can_bus_off(): print scheduling of restart if activated

2020-09-21T08:13:17Z

If a CAN device goes into bus-off and has automatic restart enabled, inform user that a automatic restart is scheduled after the configured delay. Link: https://lore.kernel.org/r/20200915223527.1417033-14-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: dev: can_change_state(): print human readable state change messages

2020-09-21T08:13:17Z

In order to ease debugging let can_change_state() print the human readable state change messages. Also print the old and new state. Link: https://lore.kernel.org/r/20200915223527.1417033-13-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: dev: can_put_echo_skb(): propagate error in case of errors

2020-09-21T08:13:16Z

The function can_put_echo_skb() can fail for several reasons. It may fail due to OOM, but when it fails it's usually due to locking problems in the driver. In order to help developing and debugging of new drivers propagate error value in case of errors. Link: https://lore.kernel.org/r/20200915223527.1417033-12-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde