Re: [PATCH] PCI: Avoid work_on_cpu() in async probe workers

[Tejun Heo]

On Sat, Dec 27, 2025 at 07:33:26PM +0800, Jinhui Guo wrote:
> To fix the issue, pci_call_probe() must not call work_on_cpu() when it is
> already running inside an unbounded asynchronous worker. Because a driver
> can be probed asynchronously either by probe_type or by the kernel command
> line, we cannot rely on PROBE_PREFER_ASYNCHRONOUS alone. Instead, we test
> the PF_WQ_WORKER flag in current->flags; if it is set, pci_call_probe() is
> executing within an unbounded workqueue worker and should skip the extra
> work_on_cpu() call.

Why not just use queue_work_on() on system_dfl_wq (or any other unbound
workqueue)? Those are soft-affine to cache domain but can overflow to other
CPUs?

Thanks.

-- 
tejun