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Date: Thu, 5 Apr 2001 19:13:08 +0300 (EEST)
From: Jani Monoses <jani@virtualro.ic.ro>
To: Bjorn Wesen <bjorn@sparta.lu.se>
cc: linux-kernel@vger.kernel.org
Subject: Re: ERESTARTSYS question.
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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? 

> When a driver needs to wait, and get awoken by a signal (as opposed to
> what it's really waiting for) the driver should in most cases abort the
> system call so the signal handler can be run (like, you push ctrl-c while
> running somethinig that's stuck in a wait for an interrupt). The kernel
> uses the ERESTARTSYS as a "magic" value saying it's ok to restart the
> system call automagically after the signal handling is done. The actual
> return-code is switched to EINTR if the system call could not be
> restarted.
> 
> -Bjorn
> 

Thanks, and by the way the comments in arch/cris regarding the issue are
useful too ;)

Jani.

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