From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817Ab2LQWdw (ORCPT ); Mon, 17 Dec 2012 17:33:52 -0500 Received: from mail-wg0-f47.google.com ([74.125.82.47]:34938 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750989Ab2LQWdv (ORCPT ); Mon, 17 Dec 2012 17:33:51 -0500 X-Greylist: delayed 399 seconds by postgrey-1.27 at vger.kernel.org; Mon, 17 Dec 2012 17:33:51 EST Date: Mon, 17 Dec 2012 23:26:38 +0100 From: "Dae S. Kim" To: arnd@arndb.de Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] char/misc.c: misc_register: Do not loop on misc_list unconditionally Message-ID: <20121217222638.GA3747@Delta> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the minor number is assigned dynamically, there is no need to search for misc->minor in misc_list, since misc->minor == MISC_DYNAMIC_MINOR. Signed-off-by: Dae S. Kim --- drivers/char/misc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index 522136d..7b262b6 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -190,12 +190,6 @@ int misc_register(struct miscdevice * misc) INIT_LIST_HEAD(&misc->list); mutex_lock(&misc_mtx); - list_for_each_entry(c, &misc_list, list) { - if (c->minor == misc->minor) { - mutex_unlock(&misc_mtx); - return -EBUSY; - } - } if (misc->minor == MISC_DYNAMIC_MINOR) { int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS); @@ -205,6 +199,13 @@ int misc_register(struct miscdevice * misc) } misc->minor = DYNAMIC_MINORS - i - 1; set_bit(i, misc_minors); + } else { + list_for_each_entry(c, &misc_list, list) { + if (c->minor == misc->minor) { + mutex_unlock(&misc_mtx); + return -EBUSY; + } + } } dev = MKDEV(MISC_MAJOR, misc->minor); -- 1.7.9.5