From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422837AbWJNTRj (ORCPT ); Sat, 14 Oct 2006 15:17:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422841AbWJNTRj (ORCPT ); Sat, 14 Oct 2006 15:17:39 -0400 Received: from mail.gmx.de ([213.165.64.20]:8353 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S1422798AbWJNTRi (ORCPT ); Sat, 14 Oct 2006 15:17:38 -0400 Content-Type: text/plain; charset="iso-8859-1" Date: Sat, 14 Oct 2006 21:17:37 +0200 From: "Philipp Kohlbecher" Message-ID: <20061014191737.323490@gmx.net> MIME-Version: 1.0 Subject: ra_pages and max_sectors To: linux-kernel@vger.kernel.org X-Authenticated: #34473864 X-Flags: 0001 X-Mailer: WWW-Mail 6100 (Global Message Exchange) X-Priority: 3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello! I was wondering why I can change the read-ahead size of my DVD drive via hdparm -a [size], but not by writing into /sys/block/hdb/queue/read_ahead_kb. In other words: Why does queue_ra_store() [block/ll_rw_blk.c:3755] perform the following check if (ra_kb > (q->max_sectors >> 1)) ra_kb = (q->max_sectors >> 1); while blkdev_locked_ioctl() [block/ioctl.c:138] does not check this in the case that cmd == BLKRASET? Thanks for your consideration, - Philipp Kohlbecher Please CC me -- I'm not on the list. -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer