Messages in this thread | | | From | Grant Likely <> | Subject | Re: [PATCH v2] driver core: add wait event for deferred probe | Date | Wed, 13 Feb 2013 21:39:59 +0000 |
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On Tue, 12 Feb 2013 10:58:35 +0800, Haojian Zhuang <haojian.zhuang@linaro.org> wrote: > do_initcalls() could call all driver initialization code in kernel_init > thread. It means that probe() function will be also called from that > time. After this, kernel could access console & release __init section > in the same thread. > > But if device probe fails and moves into deferred probe list, a new > thread is created to reinvoke probe. If the device is serial console, > kernel has to open console failure & release __init section before > reinvoking failure. Because there's no synchronization mechanism. > Now add wait event to synchronize after do_initcalls(). > > Changelog: > v2: add comments on wait_for_device_probe(). > > Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
As replied to on v1 of your patch, this change will cause a deadlock. The following change would do the same without the deadlock issue:
static int deferred_probe_initcall(void) { deferred_wq = create_singlethread_workqueue("deferwq"); if (WARN_ON(!deferred_wq)) return -ENOMEM;
driver_deferred_probe_enable = true; + deferred_probe_work_func(NULL); - driver_deferred_probe_trigger(); return 0; } late_initcall(deferred_probe_initcall);
g.
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