From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757653AbYDGMnp (ORCPT ); Mon, 7 Apr 2008 08:43:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752547AbYDGMnf (ORCPT ); Mon, 7 Apr 2008 08:43:35 -0400 Received: from ug-out-1314.google.com ([66.249.92.172]:6117 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291AbYDGMne (ORCPT ); Mon, 7 Apr 2008 08:43:34 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=HBjdy9YlGCoDhFv+cuRk4ZRhai/bFFv44D/0PKl7Wpw9c93EkzBUgRzvSyQ44x2av5FBSy8E9eGiEAxOF1XRpHZASb7rpaUm4oitvmQI3ITuicVKAId/+0yREm1+q8+pykTSg/cCO3bn+6H+T8RVVMvnITeqptPIaH+ug+ehVQ0= Message-ID: <47FA16DA.80700@gmail.com> Date: Mon, 07 Apr 2008 21:43:06 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Andrew Morton CC: Dan Williams , gregkh@suse.de, linux-kernel@vger.kernel.org, neilb@suse.de Subject: Re: [RFC PATCH] sysfs: refill attribute buffer when reading from offset 0 References: <20080405184122.2816.35845.stgit@dwillia2-linux.ch.intel.com> <20080405232959.c6504be8.akpm@linux-foundation.org> In-Reply-To: <20080405232959.c6504be8.akpm@linux-foundation.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Andrew Morton wrote: >> The application for this change is to allow a userspace >> RAID metadata handler to check the state of an array without causing any >> memory allocations. Thus not causing writeback to a raid array that might >> be blocked waiting for userspace to take action. > > Although that sounds like a rather, umm, optimistic application. I guess > if everything's mlocked you might get lucky. > >> Cc: NeilBrown >> Cc: Tejun Heo >> Signed-off-by: Dan Williams Acked-by: Tejun Heo > Has this been tested with pread()? That should work - doing an lseek+read > is plain dopey. > > Can we now remove need_read_fill? Not if we want to support > open+lseek+read, I guess - this initial read might not be at offset > zero. Heh.. needs_read_fill is set after read and poll regardless of file pos and I bet there are applications depending on it. :-( -- tejun