Oliver Hartkopp 511e64e13d can: gw: fix RCU/BH usage in cgw_create_job()
As reported by Sebastian Andrzej Siewior the use of local_bh_disable()
is only feasible in uni processor systems to update the modification rules.
The usual use-case to update the modification rules is to update the data
of the modifications but not the modification types (AND/OR/XOR/SET) or
the checksum functions itself.

To omit additional memory allocations to maintain fast modification
switching times, the modification description space is doubled at gw-job
creation time so that only the reference to the active modification
description is changed under rcu protection.

Rename cgw_job::mod to cf_mod and make it a RCU pointer. Allocate in
cgw_create_job() and free it together with cgw_job in
cgw_job_free_rcu(). Update all users to dereference cgw_job::cf_mod with
a RCU accessor and if possible once.

[bigeasy: Replace mod1/mod2 from the Oliver's original patch with dynamic
allocation, use RCU annotation and accessor]

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Closes: https://lore.kernel.org/linux-can/20231031112349.y0aLoBrz@linutronix.de/
Fixes: dd895d7f21 ("can: cangw: introduce optional uid to reference created routing jobs")
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250429070555.cs-7b_eZ@linutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2025-05-06 15:55:36 +02:00
2024-09-01 20:43:24 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
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