can: bcm: use call_rcu() instead of costly synchronize_rcu()
commit f1b4e32a upstream. In commit d5f9023f ("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 181d4447 ("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: d5f9023f ("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>
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