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From: Manfred Spraul <manfred@colorfullife.com>
To: Teemu Koponen <tkoponen@iki.fi>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Opening of blocking FIFOs not reliable?
Date: Sun, 14 Aug 2005 12:15:08 +0200	[thread overview]
Message-ID: <42FF19AC.6010502@colorfullife.com> (raw)

Teemu wrote:

>Opening a FIFO for WR_ONLY should release a previously blocked RD_ONLY 
>open. I suspect this is not guaranteed on a heavily loaded Linux box.
>  
>
Do you have a test case?
IIRC we had that bug, and it was fixed by adding PIPE_WCOUNTER:
PIPE_WRITERS counts the number of writers. This one is decreased during 
close(). PIPE_WCOUNTER counts how often a writer was seen. It's never 
decreased. Readers that wait for a writer wait until PIPE_WCOUNTER 
changes, they do not look at PIPE_WRITERS.

--
    Manfred

             reply	other threads:[~2005-08-14 10:15 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-14 10:15 Manfred Spraul [this message]
2005-08-14 10:40 ` Opening of blocking FIFOs not reliable? Teemu Koponen
  -- strict thread matches above, loose matches on Subject: below --
2005-08-13  3:18 Teemu Koponen
2005-08-14  0:49 ` Alan Cox

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