From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: [PATCH 4/5] sata_nv: Use notifier for completion checks Date: Mon, 19 Feb 2007 19:03:08 -0600 Message-ID: <45DA48CC.3090704@shaw.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from shawidc-mo1.cg.shawcable.net ([24.71.223.10]:56367 "EHLO pd3mo3so.prod.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932844AbXBTBFs (ORCPT ); Mon, 19 Feb 2007 20:05:48 -0500 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-kernel , linux-ide@vger.kernel.org, Jeff Garzik , Andrew Morton The hardware provides us a notifier register that indicates what command tags have completed. Use this to determine which CPBs to check, rather than blindly checking all active CPBs. This should provide a minor performance win, since if the controller has touched some of these incomplete CPBs, accessing them will likely result in a cache miss. Signed-off-by: Robert Hancock --- linux-2.6.20-git6edit/drivers/ata/sata_nv.c 2007-02-15 22:36:02.000000000 -0600 +++ linux-2.6.20-git6edit/drivers/ata/sata_nv.c.delayandfixes 2007-02-19 17:00:14.000000000 -0600 @@ -853,22 +854,14 @@ static irqreturn_t nv_adma_interrupt(int if (status & (NV_ADMA_STAT_DONE | NV_ADMA_STAT_CPBERR)) { + u32 check_commands = notifier | notifier_error; + int pos, error = 0; /** Check CPBs for completed commands */ - - if (ata_tag_valid(ap->active_tag)) { - /* Non-NCQ command */ - nv_adma_check_cpb(ap, ap->active_tag, - notifier_error & (1 << ap->active_tag)); - } else { - int pos, error = 0; - u32 active = ap->sactive; - - while ((pos = ffs(active)) && !error) { - pos--; - error = nv_adma_check_cpb(ap, pos, - notifier_error & (1 << pos) ); - active &= ~(1 << pos ); - } + while ((pos = ffs(check_commands)) && !error) { + pos--; + error = nv_adma_check_cpb(ap, pos, + notifier_error & (1 << pos) ); + check_commands &= ~(1 << pos ); } } }