Re: [PATCH net V2 2/4] net/mlx5: Fix deadlock between devlink lock and esw->wq
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-02-03 00:29:50
Also in:
linux-rdma, lkml
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-02-03 00:29:50
Also in:
linux-rdma, lkml
On Mon, 2 Feb 2026 14:48:28 +0000 Cosmin Ratiu wrote:
quoted
And having a refount on (I presume) struct mlx5_esw_functions so that work can hold a ref is not an option? Are you planning to revisit this in -next?Currently, mlx5_eswitch_disable_locked (with the devlink lock held) waits for esw_vfs_changed_event_handler to finish. The event handler needs to acquire the same lock and load/unload all VFs, which touches the entire esw. I don't currently see how to use reference counting on the esw to avoid waiting for the handler.
struct my_thing_with_work {
work;
refcount;
dead;
};
work() {
lock()
if (my_thing->dead)
goto out;
/* .. add code here .. */
out:
unlock()
my_thing_put(my_thing)
}
some_op() {
// assuming lock() held
if (!work_queued(my_thing->work)) {
refcount_inc(my_thing->refcount);
queue_work(my_thing->work)
}
}
shutdown_op() {
// assuming lock() held
if (cancel_work())
my_thing_put(my_thing)
my_thing->dead = true;
my_thing_put(my_thing)
}