linux.git/include/linux/can, branch v5.11

can: drivers: introduce helpers to access Classical CAN DLC values

2020-11-20T11:05:14+00:00

This patch adds the following helper to functions to access Classical CAN DLC
values.

can_get_cc_dlc(): get the data length code for Classical CAN raw DLC access
can_frame_set_cc_len(): set len and len8_dlc value for Classical CAN raw DLC access

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201110154913.1404582-2-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: rename CAN FD related can_len2dlc and can_dlc2len helpers

2020-11-20T11:05:14+00:00

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

2020-11-20T11:04:12+00:00

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: remove obsolete get_canfd_dlc() macro

2020-11-20T08:43:30+00:00

The macro was always used together with can_dlc2len() which sanitizes the
given dlc value on its own.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201110101852.1973-4-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: rename get_can_dlc() macro with can_cc_dlc2len()

2020-11-20T08:43:29+00:00

The get_can_dlc() macro is used to ensure the payload length information of
the Classical CAN frame to be max 8 bytes (the CAN_MAX_DLEN).

Rename the macro and use the correct constant in preparation of the len/dlc
cleanup for Classical CAN frames.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201110101852.1973-3-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: can_create_echo_skb(): fix echo skb generation: always use skb_clone()

2020-11-03T21:30:31+00:00

All user space generated SKBs are owned by a socket (unless injected into the
key via AF_PACKET). If a socket is closed, all associated skbs will be cleaned
up.

This leads to a problem when a CAN driver calls can_put_echo_skb() on a
unshared SKB. If the socket is closed prior to the TX complete handler,
can_get_echo_skb() and the subsequent delivering of the echo SKB to all
registered callbacks, a SKB with a refcount of 0 is delivered.

To avoid the problem, in can_get_echo_skb() the original SKB is now always
cloned, regardless of shared SKB or not. If the process exists it can now
safely discard its SKBs, without disturbing the delivery of the echo SKB.

The problem shows up in the j1939 stack, when it clones the incoming skb, which
detects the already 0 refcount.

We can easily reproduce this with following example:

testj1939 -B -r can0: &
cansend can0 1823ff40#0123

WARNING: CPU: 0 PID: 293 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x174
refcount_t: addition on 0; use-after-free.
Modules linked in: coda_vpu imx_vdoa videobuf2_vmalloc dw_hdmi_ahb_audio vcan
CPU: 0 PID: 293 Comm: cansend Not tainted 5.5.0-rc6-00376-g9e20dcb7040d #1
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
[] (dump_backtrace) from [] (show_stack+0x20/0x24)
[] (show_stack) from [] (dump_stack+0x8c/0xa0)
[] (dump_stack) from [] (__warn+0xe0/0x108)
[] (__warn) from [] (warn_slowpath_fmt+0xa8/0xcc)
[] (warn_slowpath_fmt) from [] (refcount_warn_saturate+0x108/0x174)
[] (refcount_warn_saturate) from [] (j1939_can_recv+0x20c/0x210)
[] (j1939_can_recv) from [] (can_rcv_filter+0xb4/0x268)
[] (can_rcv_filter) from [] (can_receive+0xb0/0xe4)
[] (can_receive) from [] (can_rcv+0x48/0x98)
[] (can_rcv) from [] (__netif_receive_skb_one_core+0x64/0x88)
[] (__netif_receive_skb_one_core) from [] (__netif_receive_skb+0x38/0x94)
[] (__netif_receive_skb) from [] (netif_receive_skb_internal+0x64/0xf8)
[] (netif_receive_skb_internal) from [] (netif_receive_skb+0x34/0x19c)
[] (netif_receive_skb) from [] (can_rx_offload_napi_poll+0x58/0xb4)

Fixes: 0ae89beb283a ("can: add destructor for self generated skbs")
Signed-off-by: Oleksij Rempel 
Link: http://lore.kernel.org/r/20200124132656.22156-1-o.rempel@pengutronix.de
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: remove obsolete version strings

2020-10-12T08:06:39+00:00

As pointed out by Jakub Kicinski here:
http://lore.kernel.org/r/20201009175751.5c54097f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com
this patch removes the obsolete version information of the different
CAN protocols and the AF_CAN core module.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201012074354.25839-2-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

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

2020-10-07T21:17:45+00:00

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: fix type of get_can_dlc() and get_canfd_dlc() macros

2020-10-06T20:44:27+00:00

The macros get_can_dlc() and get_canfd_dlc() are not visible in
userland. As such, type u8 should be preferred over type __u8.

Reference: https://lkml.org/lkml/2020/10/1/708
Signed-off-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20201002154219.4887-3-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde

can: rx-offload: can_rx_offload_add_manual(): add new initialization function

2020-09-21T08:13:19+00:00

This patch adds a new initialization function:
can_rx_offload_add_manual()

It should be used to add support rx-offload to a driver, if the callback
mechanism should not be used. Use e.g. can_rx_offload_queue_sorted() to queue
skbs into rx-offload.

Link: https://lore.kernel.org/r/20200915223527.1417033-33-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde