Messages in this thread | | | Date | Sun, 02 Aug 2009 01:37:12 +0200 | From | Tilman Schmidt <> | Subject | Re: [PATCH 2.6.31-rc4] gigaset: really fix chars_in_buffer |
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Hi Alan,
thanks a lot for getting in contact with me, and for your explanation of the rationale behind your patch.
On Sat, 1 Aug 2009 17:11:41 +0100, Alan Cox wrote: > Is that correct. If you take a signal so the mutex_lock_interruptible > takes the error path we'll exit any waits for characters to be flushed > from buffers and lose the bytes in some cases ?
You are right. I'll have to change it to use non-interruptible mutex_lock. I'll prepare a new patch.
> Thats why I didn't > convert it - I didn't understand why it was using _interruptible at all ?
No specific reason. just the general rule to prefer sleeping interuptibly whenever possible, because unkillable processes are so annoying. Seeing that chars_in_buffer was declared as returning int, I assumed (wrongly as it now turns out) that it would be allowed to return the customary negative values for errors, so that it could use the _interruptible variant. When I saw your patch I read into it that zero would be the appropriate return value for all error cases, including a signal while waiting for the mutex. I guess there was a bit of wishful thinking in that.
Well, thanks again for your help. I'll follow up with a revised patch.
Regards, Tilman
-- Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Ungeöffnet mindestens haltbar bis: (siehe Rückseite)
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