Messages in this thread | | | Date | Thu, 5 Apr 2001 17:02:42 +0200 (MET DST) | From | Bjorn Wesen <> | Subject | Re: ERESTARTSYS question. |
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On Thu, 5 Apr 2001, Jani Monoses wrote: > On Thu, 5 Apr 2001, Bjorn Wesen wrote: > > ERESTARTSYS is a part of the api between the driver and the > > signal-handling code in the kernel. It does not reach user-space (provided > > of course that it's used appropriately in the drivers :) > > As an example sound/via82cxxx_audio.c returns ERESTARTSYS from > via_dsp_open() .I suppose this _does_ reach userland right?
No; system calls do not exit directly to userland, they exit through the magic in entry.S (confusingly so :). If a signal is pending (which it is, if down_interruptible fails) the return is made through do_signal, which rewrites the return value and does the proper restarting.
(down_interruptible means it can be interrupted by a signal, btw - bad drivers do sleep and semaphoring without _interruptible so if your HW is bad the process can get stuck irrecoverably in the kernel)
/Bjorn
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