From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757192AbYIDMx3 (ORCPT ); Thu, 4 Sep 2008 08:53:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751543AbYIDMxR (ORCPT ); Thu, 4 Sep 2008 08:53:17 -0400 Received: from palinux.external.hp.com ([192.25.206.14]:43463 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399AbYIDMxQ (ORCPT ); Thu, 4 Sep 2008 08:53:16 -0400 Date: Thu, 4 Sep 2008 06:52:19 -0600 From: Matthew Wilcox To: Stephen Hemminger Cc: Ben Hutchings , Jesse Barnes , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH 1/3] pci: VPD access timeout increase Message-ID: <20080904125219.GJ2772@parisc-linux.org> References: <20080827204626.4b65862f@extreme> <20080828111323.GI7908@solarflare.com> <20080903155713.7fab2e19@extreme> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080903155713.7fab2e19@extreme> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 03, 2008 at 03:57:13PM -0700, Stephen Hemminger wrote: > Accessing the VPD area can take a long time. There are comments in the > SysKonnect vendor driver that it can take up to 25ms. The existing vpd > access code fails consistently on my hardware. Wow, that's slow. If you were to try to read all 32k, it'd take more than three minutes! (I presume it doesn't actually have as much as 32k). > Change the access routines to: > * use a mutex rather than spinning with IRQ's disabled and lock held > * have a longer timeout > * call schedule while spinning to provide some responsivness I agree with your approach, but have one minor comment: > - spin_lock_irq(&vpd->lock); > + mutex_lock(&vpd->lock); This should be: + if (mutex_lock_interruptible(&vpd->lock)) + return -EINTR; > @@ -231,7 +232,7 @@ static int pci_vpd_pci22_write(struct pc > val |= ((u8) *buf++) << 16; > val |= ((u32)(u8) *buf++) << 24; > > - spin_lock_irq(&vpd->lock); > + mutex_lock(&vpd->lock); And the same here, of course. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."