linux.git/net/can, branch v5.4-rc2

can: add support of SAE J1939 protocol

2019-09-04T12:22:33+00:00

SAE J1939 is the vehicle bus recommended practice used for communication
and diagnostics among vehicle components. Originating in the car and
heavy-duty truck industry in the United States, it is now widely used in
other parts of the world.

J1939, ISO 11783 and NMEA 2000 all share the same high level protocol.
SAE J1939 can be considered the replacement for the older SAE J1708 and
SAE J1587 specifications.

Acked-by: Oliver Hartkopp 
Signed-off-by: Bastian Stender 
Signed-off-by: Elenita Hinds 
Signed-off-by: kbuild test robot 
Signed-off-by: Kurt Van Dijck 
Signed-off-by: Maxime Jayat 
Signed-off-by: Robin van der Gracht 
Signed-off-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: introduce CAN_REQUIRED_SIZE macro

2019-09-04T11:29:15+00:00

The size of this structure will be increased with J1939 support. To stay
binary compatible, the CAN_REQUIRED_SIZE macro is introduced for
existing CAN protocols.

Signed-off-by: Kurt Van Dijck 
Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: af_can: use spin_lock_bh() for &net->can.rcvlists_lock

2019-09-04T11:29:15+00:00

The can_rx_unregister() can be called from NAPI (soft IRQ) context, at least
by j1939 stack. This leads to potential dead lock with &net->can.rcvlists_lock
called from can_rx_register:
===============================================================================
 WARNING: inconsistent lock state
 4.19.0-20181029-1-g3e67f95ba0d3 #3 Not tainted
 --------------------------------
 inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
 testj1939/224 [HC0[0]:SC1[1]:HE1:SE0] takes:
 1ad0fda3 (&(&net->can.rcvlists_lock)->rlock){+.?.}, at: can_rx_unregister+0x4c/0x1ac
 {SOFTIRQ-ON-W} state was registered at:
   lock_acquire+0xd0/0x1f4
   _raw_spin_lock+0x30/0x40
   can_rx_register+0x5c/0x14c
   j1939_netdev_start+0xdc/0x1f8
   j1939_sk_bind+0x18c/0x1c8
   __sys_bind+0x70/0xb0
   sys_bind+0x10/0x14
   ret_fast_syscall+0x0/0x28
   0xbedc9b64
 irq event stamp: 2440
 hardirqs last  enabled at (2440): [] __local_bh_enable_ip+0xac/0x184
 hardirqs last disabled at (2439): [] __local_bh_enable_ip+0x60/0x184
 softirqs last  enabled at (2412): [] release_sock+0x84/0xa4
 softirqs last disabled at (2415): [] irq_exit+0x100/0x1b0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&(&net->can.rcvlists_lock)->rlock);
   
     lock(&(&net->can.rcvlists_lock)->rlock);

  *** DEADLOCK ***

 2 locks held by testj1939/224:
  #0: 168eb13b (rcu_read_lock){....}, at: netif_receive_skb_internal+0x3c/0x350
  #1: 168eb13b (rcu_read_lock){....}, at: can_receive+0x88/0x1c0
===============================================================================

To avoid this situation, we should use spin_lock_bh() instead of spin_lock().

Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: af_can: remove NULL-ptr checks from users of can_dev_rcv_lists_find()

2019-09-04T11:29:15+00:00

Since using the "struct can_ml_priv" for the per device "struct
dev_rcv_lists" the call can_dev_rcv_lists_find() cannot fail anymore.
This patch simplifies af_can by removing the NULL pointer checks from
the dev_rcv_lists returned by can_dev_rcv_lists_find().

Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: make use of preallocated can_ml_priv for per device struct can_dev_rcv_lists

2019-09-04T11:29:15+00:00

This patch removes the old method of allocating the per device protocol
specific memory via a netdevice_notifier. This had the drawback, that
the allocation can fail, leading to a lot of null pointer checks in the
code. This also makes the live cycle management of this memory quite
complicated.

This patch switches from the allocating the struct can_dev_rcv_lists in
a NETDEV_REGISTER call to using the dev->ml_priv, which is allocated by
the driver since the previous patch.

Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: introduce CAN midlayer private and allocate it automatically

2019-09-04T11:29:14+00:00

This patch introduces the CAN midlayer private structure ("struct
can_ml_priv") which should be used to hold protocol specific per device
data structures. For now it's only member is "struct can_dev_rcv_lists".

The CAN midlayer private is allocated via alloc_netdev()'s private and
assigned to "struct net_device::ml_priv" during device creation. This is
done transparently for CAN drivers using alloc_candev(). The slcan, vcan
and vxcan drivers which are not using alloc_candev() have been adopted
manually. The memory layout of the netdev_priv allocated via
alloc_candev() will looke like this:

  +-------------------------+
  | driver's priv           |
  +-------------------------+
  | struct can_ml_priv      |
  +-------------------------+
  | array of struct sk_buff |
  +-------------------------+

Signed-off-by: Oleksij Rempel 
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: af_can: can_pernet_exit(): no need to iterate over and cleanup registered CAN devices

2019-09-04T11:29:14+00:00

The networking core takes care and unregisters every network device in
a namespace before calling the can_pernet_exit() hook. This patch
removes the unneeded cleanup.

Acked-by: Oliver Hartkopp 
Suggested-by: Kirill Tkhai 
Signed-off-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: af_can: can_rx_register(): use max() instead of open coding it

2019-09-04T11:29:14+00:00

This patch replaces an open coded max by the proper kernel define max().

Acked-by: Oliver Hartkopp 
Signed-off-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: af_can: give variable holding the CAN receiver and the receiver list a sensible name

2019-09-04T11:29:14+00:00

This patch gives the variables holding the CAN receiver and the receiver
list a better name by renaming them from "r to "rcv" and "rl" to
"recv_list".

Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: af_can: rename find_dev_rcv_lists() to can_dev_rcv_lists_find()

2019-09-04T11:29:14+00:00

This patch add the commonly used prefix "can_" to the find_dev_rcv_lists()
function and moves the "find" to the end, as the function returns a struct
can_dev_rcv_list. This improves the overall readability of the code.

Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde