Messages in this thread | | | Date | Mon, 14 Jan 2008 18:38:06 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH] driver: ip27-rtc - convert ioctl to unlocked_ioctl |
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[Jiri Slaby - Mon, Jan 14, 2008 at 04:14:18PM +0100] > On 01/14/2008 07:38 AM, Cyrill Gorcunov wrote: >> This patch converts ioctl call to unlocked_ioctl form. It's possible >> due to rtl_lock spinlock protection. >> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com> >> --- >> The patch is *not* tested but the patch does not bring _much_ changes >> so it wouldn't break the compilation procedure. >> If there is problem with attachment - i could send it as inline >> form today evening. > > Yes, please, especially if it is app/octet-stream (base64 encoded > plaintext). Also Cc akpm or somebody who will pick your patch up. >
ok
>> Andi, Jiri, Alexey the only thing I do complain about - >> is time set/read from several user threads that uses same >> (duplicated) file descriptor. Could there be useless thread >> spins instead of sleep (in case if this unlocked_ioctl were >> protected by mutex)? > > Sorry, what? >
Jiri, I mean rtc_open() is protected by spinlock+status from being opened simultaneously by a few processes. *But* lets imagine the following situation - this fd (file descriptor) is opened by one multithreaded application so all threads have an access to this fd. Then one thread reads rtc periodically thru unlocked_ioctl and another thread set new time from time to time. So the question I have - is it possible to get second thread stopped at attemption to get rtc spinlock while another thread is setting the new time? Or this situation never-ever could be? i'm not really familiar with process management in Linux and as result could be wrong.
- Cyrill -
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