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From: Helge Deller <deller@gmx.de>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Carlos O'Donell <carlos@systemhalted.org>,
	Kyle McMartin <kyle@infradead.org>,
	linux-arch@vger.kernel.org, Stefan Fritsch <sf@sfritsch.de>,
	debian-hppa@lists.debian.org
Subject: Re: flock, FAGAIN, and FWOULDBLOCK
Date: Mon, 23 Feb 2009 18:49:24 +0100	[thread overview]
Message-ID: <49A2E1A4.8010607@gmx.de> (raw)
In-Reply-To: <20090223030315.GC16891@parisc-linux.org>

Matthew Wilcox wrote:
> On Sun, Feb 22, 2009 at 09:43:36PM -0500, Carlos O'Donell wrote:
>>> ...
>>> but somehow I suspect this interchangeable use of EAGAIN and EWOULDBLOCK
>>> is going to reveal latent problems in this part of the kernel I would
>>> rather not delve into...
>> The ABI is fixed, so all we can do is cleanup the uses in the kernel,
>> and make sure we adhere to the documented APIs.
> 
> We actually can do better than this ...
> 
> #ifdef __KERNEL__
> #define EWOULDBLOCK	EAGAIN
> #else
> #define EWOULDBLOCK	/* whatever the fuck HPUX uses */
> #endif

Wouldn't this hurt us if we at some point in time want to finish 
the HPUX/Linux compat code in the parisc kernel?

Helge

> Now our kernel never returns -EWOULDBLOCK, only -EAGAIN.  Correct
> applications must check for both.  Incorrect applications tend to only
> check for AGAIN, not WOULDBLOCK.  Problem solved.

  parent reply	other threads:[~2009-02-23 17:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200902222252.45051.sf@sfritsch.de>
     [not found] ` <20090222224924.GA13157@bombadil.infradead.org>
2009-02-23  1:42   ` flock, FAGAIN, and FWOULDBLOCK Kyle McMartin
2009-02-23  2:43     ` Carlos O'Donell
2009-02-23  2:43       ` Carlos O'Donell
2009-02-23  2:54       ` Kyle McMartin
2009-02-23  3:00         ` Carlos O'Donell
2009-02-23  3:03       ` Matthew Wilcox
2009-02-23  3:55         ` Michael Kerrisk
2009-02-23 17:49         ` Helge Deller [this message]
2009-02-23 19:31         ` flock, EAGAIN, and EWOULDBLOCK Stefan Fritsch
2009-02-23 19:31           ` Stefan Fritsch
2009-02-23  3:31       ` flock, FAGAIN, and FWOULDBLOCK Michael Kerrisk
2009-02-23  3:20     ` Michael Kerrisk
2009-02-23  3:50       ` Kyle McMartin
2009-02-23  4:01         ` Michael Kerrisk
2009-02-23  8:23       ` Geert Uytterhoeven

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