linux-stable/net/can
Oliver Hartkopp f34f2a18e4 can: bcm: use call_rcu() instead of costly synchronize_rcu()
commit f1b4e32aca upstream.

In commit d5f9023fa6 ("can: bcm: delay release of struct bcm_op
after synchronize_rcu()") Thadeu Lima de Souza Cascardo introduced two
synchronize_rcu() calls in bcm_release() (only once at socket close)
and in bcm_delete_rx_op() (called on removal of each single bcm_op).

Unfortunately this slow removal of the bcm_op's affects user space
applications like cansniffer where the modification of a filter
removes 2048 bcm_op's which blocks the cansniffer application for
40(!) seconds.

In commit 181d444790 ("can: gw: use call_rcu() instead of costly
synchronize_rcu()") Eric Dumazet replaced the synchronize_rcu() calls
with several call_rcu()'s to safely remove the data structures after
the removal of CAN ID subscriptions with can_rx_unregister() calls.

This patch adopts Erics approach for the can-bcm which should be
applicable since the removal of tasklet_kill() in bcm_remove_op() and
the introduction of the HRTIMER_MODE_SOFT timer handling in Linux 5.4.

Fixes: d5f9023fa6 ("can: bcm: delay release of struct bcm_op after synchronize_rcu()") # >= 5.4
Link: https://lore.kernel.org/all/20220520183239.19111-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>
Cc: Norbert Slusarek <nslusarek@gmx.net>
Cc: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-12 16:34:48 +02:00
..
j1939 net-timestamp: convert sk->sk_tskey to atomic_t 2022-03-02 11:48:01 +01:00
af_can.c net: introduce CAN specific pointer in the struct net_device 2021-02-24 14:32:15 -08:00
af_can.h can: introduce CAN midlayer private and allocate it automatically 2019-09-04 13:29:14 +02:00
bcm.c can: bcm: use call_rcu() instead of costly synchronize_rcu() 2022-07-12 16:34:48 +02:00
gw.c can: gw: synchronize rcu operations before removing gw job entry 2021-06-19 23:53:43 +02:00
isotp.c can: isotp: remove re-binding of bound socket 2022-05-12 12:30:09 +02:00
Kconfig net: remove redundant 'depends on NET' 2021-01-27 17:04:12 -08:00
Makefile can: add ISO 15765-2:2016 transport protocol 2020-10-07 23:18:33 +02:00
proc.c can: proc: remove unnecessary variables 2021-05-27 09:42:21 +02:00
raw.c net: Remove redundant if statements 2021-08-05 13:27:50 +01:00