I would like to move netconsole to use RCU on the hot path for a while instead of target_list_lock. My goal is to have no lock on the tx side at all and eventually drop CON_NBCON_ATOMIC_UNSAFE, if that is possible [1].
Start removing target_list_lock on certain parts of the code. This patch transforms the userdata array into a RCU-protected pointer, and uses the dynamic mutex as the write lock. Added a selftest, given we didn't have any netconsole selftest for userdata operations. Feel free to drop it if this is not useful, dear maintainers. Link: https://lore.kernel.org/all/[email protected]/[1] Signed-off-by: Breno Leitao <[email protected]> --- Changes in v2: - netconsole: free the payload with kfree(rcu_access_pointer()) in the teardown paths, silencing a sparse __rcu warning (Gustavo Luiz Duarte) - selftest: reap every torture worker before reporting a failure, so none is left writing to configfs while the exit trap runs - Link to v1: https://patch.msgid.link/[email protected] --- Breno Leitao (2): netconsole: publish the userdata payload with RCU selftests: netconsole: add a userdata torture test drivers/net/netconsole.c | 92 +++++---- .../selftests/drivers/net/netconsole/Makefile | 1 + .../drivers/net/netconsole/netcons_userdata.sh | 229 +++++++++++++++++++++ 3 files changed, 286 insertions(+), 36 deletions(-) --- base-commit: 8ba098e6b6ff0db8edf28528d1552be261af30d4 change-id: 20260801-netcons-userdata-rcu-40446e018f86 Best regards, -- Breno Leitao <[email protected]>
