From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932606Ab1DYUoF (ORCPT ); Mon, 25 Apr 2011 16:44:05 -0400 Received: from 1wt.eu ([62.212.114.60]:34330 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932275Ab1DYUYt (ORCPT ); Mon, 25 Apr 2011 16:24:49 -0400 Message-Id: <20110425200238.001353480@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 25 Apr 2011 22:04:27 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: Mike Miller , Jens Axboe , Greg Kroah-Hartman Subject: [PATCH 115/173] cciss: fix lost command issue In-Reply-To: <46075c3a3ef08be6d70339617d6afc98@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.59-stable review patch. If anyone has any objections, please let us know. ------------------ From: Bud Brown commit 1ddd5049545e0aa1a0ed19bca4d9c9c3ce1ac8a2 upstream. Under certain workloads a command may seem to get lost. IOW, the Smart Array thinks all commands have been completed but we still have commands in our completion queue. This may lead to system instability, filesystems going read-only, or even panics depending on the affected filesystem. We add an extra read to force the write to complete. Testing shows this extra read avoids the problem. Signed-off-by: Mike Miller Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/block/cciss.h | 1 + 1 file changed, 1 insertion(+) --- a/drivers/block/cciss.h +++ b/drivers/block/cciss.h @@ -165,6 +165,7 @@ static void SA5_submit_command( ctlr_inf printk("Sending %x - down to controller\n", c->busaddr ); #endif /* CCISS_DEBUG */ writel(c->busaddr, h->vaddr + SA5_REQUEST_PORT_OFFSET); + readl(h->vaddr + SA5_REQUEST_PORT_OFFSET); h->commands_outstanding++; if ( h->commands_outstanding > h->max_outstanding) h->max_outstanding = h->commands_outstanding;