From patchwork Tue Jul  5 06:40:10 2011
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: Michael Neuling <mikey@neuling.org>
X-Patchwork-Id: 103203
Return-Path: 
 <linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>
X-Original-To: patchwork-incoming@ozlabs.org
Delivered-To: patchwork-incoming@ozlabs.org
Received: from ozlabs.org (localhost [IPv6:::1])
	by ozlabs.org (Postfix) with ESMTP id AC89D100AB8
	for <patchwork-incoming@ozlabs.org>;
	Tue,  5 Jul 2011 16:40:17 +1000 (EST)
Received: from localhost.localdomain (localhost [127.0.0.1])
	by ozlabs.org (Postfix) with ESMTP id DCE6B1007D1;
	Tue,  5 Jul 2011 16:40:10 +1000 (EST)
Received: by localhost.localdomain (Postfix, from userid 1000)
	id BFC4DC39C9; Tue,  5 Jul 2011 16:40:10 +1000 (EST)
Received: from neuling.org (localhost [127.0.0.1])
	by localhost.localdomain (Postfix) with ESMTP id BA9F2C3587;
	Tue,  5 Jul 2011 16:40:10 +1000 (EST)
From: Michael Neuling <mikey@neuling.org>
To: Anton Blanchard <anton@samba.org>
Subject: [PATCH] powerpc/kdump: Fix timeout in crash_kexec_wait_realmode
In-reply-to: <20110705161202.62dc7d24@kryten>
References: <20110705161202.62dc7d24@kryten>
Comments: In-reply-to Anton Blanchard <anton@samba.org>
	message dated "Tue, 05 Jul 2011 16:12:02 +1000."
X-Mailer: MH-E 8.2; nmh 1.3; GNU Emacs 23.2.1
Date: Tue, 05 Jul 2011 16:40:10 +1000
Message-ID: <29259.1309848010@neuling.org>
Cc: linuxppc-dev@lists.ozlabs.org
X-BeenThere: linuxppc-dev@lists.ozlabs.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Linux on PowerPC Developers Mail List
	<linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
	<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
	<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>
MIME-Version: 1.0
Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org
Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org

The existing code it pretty ugly.  How about we clean it up even more
like this?

From: Anton Blanchard <anton@samba.org>

We check for timeout expiry in the outer loop, but we also need to
check it in the inner loop or we can lock up forever waiting for a
CPU to hit real mode.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@kernel.org>

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 4e6ee94..cc6a9d5 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -242,12 +242,8 @@ static void crash_kexec_wait_realmode(int cpu)
 
 		while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) {
 			barrier();
-			if (!cpu_possible(i)) {
+			if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
 				break;
-			}
-			if (!cpu_online(i)) {
-				break;
-			}
 			msecs--;
 			mdelay(1);
 		}