Am 11.12.2017 um 12:46 schrieb Johannes Berg:
>
>> + spin_lock_bh(&hwsim_delete_lock);
>> + while (!list_empty(&delete_radios)) {
>> + pr_debug("mac80211_hwsim: wait for deferred radio remove\n");
>> + spin_unlock_bh(&hwsim_delete_lock);
>> + flush_work(&list_entry(&delete_radios,
>> + struct mac80211_hwsim_data, list)
>> + ->destroy_work);
> This can't possibly be right ... you're locking the list_empty which is
> a trivial pointer comparison, but not the actual list_entry() ...
Maybe the first spin_lock is not needed, but since flush_work wait for
the completion of the task, which at the end also deletes the item from
the list, holding any spin_lock would be wrong.
>
> I'd also prefer you actually didn't leave the problem in part as you
> describe - and a new workqueue probably isn't that much overhead and
> should introduce *less* new code than this, so IMHO that's worth it.
I totally agree with you, but I don't know the actual policy for
creating workqeues. I could also simply call flush_scheduled_work,
because we may have enough time at module unload. Some modules also do
it, but the description an some mailing threads mark it like
evil/deprecated. Which solution do you prefer?
kind regards
Benjamin
--
M.Sc. Benjamin Beichler
Universität Rostock, Fakultät für Informatik und Elektrotechnik
Institut für Angewandte Mikroelektronik und Datentechnik
University of Rostock, Department of CS and EE
Institute of Applied Microelectronics and CE
Richard-Wagner-Straße 31
18119 Rostock
Deutschland/Germany
phone: +49 (0) 381 498 - 7278
email: Benjamin.Beichler@xxxxxxxxxxxxxx
www: http://www.imd.uni-rostock.de/
