Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754521Ab3E2QKu (ORCPT ); Wed, 29 May 2013 12:10:50 -0400 Received: from mga11.intel.com ([192.55.52.93]:47075 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752355Ab3E2QKm (ORCPT ); Wed, 29 May 2013 12:10:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,765,1363158000"; d="scan'208";a="345174361" From: Youquan Song To: gregkh@linuxfoundation.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Cc: Youquan Song , Youquan Song Subject: [PATCH] core: Fix maxcpus boot option broken Date: Thu, 30 May 2013 00:00:06 -0400 Message-Id: <1369886406-14079-1-git-send-email-youquan.song@intel.com> X-Mailer: git-send-email 1.6.4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1461 Lines: 39 maxcpus boot option to limit maximum number of CPUs on system, but this option is broken at recent kernel. Though we use maxcpus to limit CPUs number, but current kernel will register all of present CPUs in sysfs. udev will enumerate all registered cpu at sysfs, and it will bring up the CPU if the CPU is offline. So the maxcpus option is broken. This patch will only register the CPU which is not over limitation of maxcpus option in sysfs. So it will keep the maxcpus limitation when udev enumeration or other intention of bring up CPUs over the limitation by method like echo 1 > /sys/devices/system/cpu/online Signed-off-by: Youquan Song --- drivers/base/cpu.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 3d48fc8..c7d603a 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -272,6 +272,10 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) { int error; + /* return when cpu number greater than maximum number of CPUs */ + if (num >= setup_max_cpus) + return 0; + cpu->node_id = cpu_to_node(num); memset(&cpu->dev, 0x00, sizeof(struct device)); cpu->dev.id = num; -- 1.7.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/