Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755859AbYFXTYm (ORCPT ); Tue, 24 Jun 2008 15:24:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752764AbYFXTYd (ORCPT ); Tue, 24 Jun 2008 15:24:33 -0400 Received: from fxip-0047f.externet.hu ([88.209.222.127]:52191 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752752AbYFXTYc (ORCPT ); Tue, 24 Jun 2008 15:24:32 -0400 To: torvalds@linux-foundation.org CC: miklos@szeredi.hu, jens.axboe@oracle.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org In-reply-to: (message from Linus Torvalds on Tue, 24 Jun 2008 12:17:44 -0700 (PDT)) Subject: Re: [rfc patch 3/4] splice: remove confirm from pipe_buf_operations References: <20080621154607.154640724@szeredi.hu> <20080621154726.494538562@szeredi.hu> <20080624080440.GJ20851@kernel.dk> <20080624111913.GP20851@kernel.dk> Message-Id: From: Miklos Szeredi Date: Tue, 24 Jun 2008 21:24:21 +0200 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1056 Lines: 27 > > > > Let's start with page_cache_pipe_buf_confirm(). How should we deal > > with finding an invalidated page (!PageUptodate(page) && > > !page->mapping)? > > I suspect we just have to use it. After all, it was valid when the read > was done. The fact that it got invalidated later is kind of immaterial. Right. But what if it's invalidated *before* becoming uptodate (if you'd read my mail further, I discussed this). Why does invalidate_complete_page2() do ClearPageUptodate()? Dunno, maybe it shoulnd't. But that would need a rather thorough audit of all code checking PageUptodate()... > splice() is an optimized read+write. The read reads it into a temporary > buffer. The fact that it's a zero-copy buffer and basically just re-uses > the source doesn't really change that. Agreed. Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/