From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759888AbXFZTHv (ORCPT ); Tue, 26 Jun 2007 15:07:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759556AbXFZTFt (ORCPT ); Tue, 26 Jun 2007 15:05:49 -0400 Received: from ns1.coraid.com ([65.14.39.133]:25149 "EHLO coraid.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759541AbXFZTFs (ORCPT ); Tue, 26 Jun 2007 15:05:48 -0400 Message-Id: <2823ea0d22cb0a4aea5a5c22bb8e6b63b2b07441.1182883861.git.ecashin@coraid.com> In-Reply-To: <1d8423c28c48a6d26516cdc707dbcdf015a4e347.1182883861.git.ecashin@coraid.com> References: <1d8423c28c48a6d26516cdc707dbcdf015a4e347.1182883861.git.ecashin@coraid.com> From: "Ed L. Cashin" Date: Tue, 26 Jun 2007 14:50:12 -0400 Subject: [PATCH 09/12] remove race between use and initialization of locks To: linux-kernel@vger.kernel.org Cc: Greg K-H , ecashin@coraid.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This change was originally submitted by Alexey Dobriyan in an email with ... Message-ID: <20070325190221.GA5308@martell.zuzino.mipt.ru> and the comment, Some drivers do register_chrdev() before lock or semaphore used in corresponding file_operations is initialized. Andrew Morton commented that these locks should be initialized at compile time, but Alexey Debriyan pointed out that the Documentation tells us to use dynamic initialization whenever possible, and then the discussion petered out. http://preview.tinyurl.com/2pxq6p I believe we made these locks dynamic because of the notice in Documentation/spinlocks.txt, which says that static initializers are deprecated: UPDATE March 21 2005 Amit Gud Macros SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED are deprecated and will be removed soon. So for any new code dynamic initialization should be used: ... In any case, the patch below makes the code correct and in keeping with the existing documentation. If the existing docs are wrong, I'd be happy to follow up with a patch that corrects them and makes these aoechr.c locks static. Signed-off-by: Alexey Dobriyan Signed-off-by: Ed L. Cashin --- drivers/block/aoe/aoechr.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c index 10b38a7..2b4f873 100644 --- a/drivers/block/aoe/aoechr.c +++ b/drivers/block/aoe/aoechr.c @@ -256,13 +256,13 @@ aoechr_init(void) { int n, i; + sema_init(&emsgs_sema, 0); + spin_lock_init(&emsgs_lock); n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); if (n < 0) { printk(KERN_ERR "aoe: can't register char device\n"); return n; } - sema_init(&emsgs_sema, 0); - spin_lock_init(&emsgs_lock); aoe_class = class_create(THIS_MODULE, "aoe"); if (IS_ERR(aoe_class)) { unregister_chrdev(AOE_MAJOR, "aoechr"); -- 1.5.2.1