Re: [PATCH, RFC 02/30] scsi: atari_scsi: fix sleep_on race

[Michael Schmitz <schmitzmic@gmail.com>]

Arnd,

this one looks like it should be changed as well:
>>> @@ -562,7 +565,10 @@ static void falcon_get_lock(void)
>>>                         falcon_trying_lock = 0;
>>>                         wake_up(&falcon_try_wait);
>>>                 } else {
>>> -                       sleep_on(&falcon_try_wait);
>>> +                       wait_event_cmd(falcon_try_wait,
>>> +                                      !falcon_got_lock && 
>>> !falcon_trying_lock,

I think using falcon_got_lock && !falcon_trying_lock here reflects what 
we try to achieve - the if branch above this will set that exact
condition, then wake the wait queue. Any other calls to falcon_get_lock 
that have been waiting on the lock should then continue on
as the lock is now held by the driver. Thoughts?

I've not see that case used in a cursory test on hardware, more stress 
testing is needed (logging lock history to a kernel buffer instead
of clogging up the console).

Cheers,

     Michael

>>> + local_irq_restore(flags),
>>> +                                      local_irq_save(flags));
>>>                 }
>>>         }
>>>
>>> -- 
>>> 1.8.3.2
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