[PATCH v4 0/3] can: rx-offload: make skb_irq_queue per-CPU

[Ciprian Costea]

From: Ciprian Marian Costea <ciprianmarian.costea at oss.nxp.com>

can_rx_offload keeps a lockless irq_queue that the IRQ handlers fill and
that is later spliced under skb_queue.lock into the NAPI-facing skb_queue.
This works as long as a single context fills the irq_queue. flexcan with
FLEXCAN_QUIRK_SECONDARY_MB_IRQ and mcf5441x use two mailbox IRQ lines. When
those are affined to different CPUs the two handlers can enqueue into the
same list at the same time and corrupt it.

This series:
  1. Makes the irq_queue per-CPU so the handlers no longer share a list.
  2. Fixes at91_can rx-offload teardown.
  3. Checks the can_rx_offload_add_manual() return value in gs_usb.

Changes since v3:

- In gs_usb driver, check the can_rx_offload_add_manual() return value,
  the same NULL-deref the per-CPU change exposes.

Changes since v2:

- at91_can: also add can_rx_offload_del() on the register_candev() error
  path and check the can_rx_offload_add_timestamp() return value.

Changes since v1:

- The enqueue helpers used this_cpu_ptr() without disabling preemption.
  All four enqueue helpers now use get_cpu_ptr()/put_cpu_ptr().
- Guard can_rx_offload_del() against skb_irq_queue == NULL.
- Fix 'at91_can' memory leak by adding missing 'can_rx_offload_del'.

Ciprian Marian Costea (3):
  can: rx-offload: make skb_irq_queue per-CPU
  can: at91_can: fix rx-offload cleanup on unbind and probe errors
  can: gs_usb: check can_rx_offload_add_manual() return value

 drivers/net/can/at91_can.c       | 10 +++-
 drivers/net/can/dev/rx-offload.c | 83 ++++++++++++++++++++++++++------
 drivers/net/can/usb/gs_usb.c     |  5 +-
 include/linux/can/rx-offload.h   |  2 +-
 4 files changed, 82 insertions(+), 18 deletions(-)

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2.43.0