Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754611Ab1DEWjS (ORCPT ); Tue, 5 Apr 2011 18:39:18 -0400 Received: from imr4.ericy.com ([198.24.6.8]:59785 "EHLO imr4.ericy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752770Ab1DEWjQ (ORCPT ); Tue, 5 Apr 2011 18:39:16 -0400 Date: Tue, 5 Apr 2011 15:38:14 -0700 From: Guenter Roeck To: Nat Gurumoorthy CC: Jean Delvare , Wim Van Sebroeck , Mike Waychison , "lm-sensors@lm-sensors.org" , "linux-kernel@vger.kernel.org" , "linux-watchdog@vger.kernel.org" Subject: Re: [PATCH] Make all it87 drivers SMP safe. Message-ID: <20110405223814.GA21350@ericsson.com> References: <1302038697-28985-1-git-send-email-natg@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1302038697-28985-1-git-send-email-natg@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2374 Lines: 42 On Tue, Apr 05, 2011 at 05:24:57PM -0400, Nat Gurumoorthy wrote: > There are 3 different drivers that touch the it87 hardware registers. > The 3 drivers have been written independently and access the it87 hardware > registers assuming they are the only driver accessing it. This change > attempts to serialize access to the hardware by defining a global spinlock > it87_io_lock in a file it87_lock.c. This lock has to be acquired by each > of the it87 drivers before it can access the hardware. We have defined > a new Kconfig option IT87_LOCK. When it is selected it87_lock.c is compiled > into the kernel thereby making the lock global and accessable to the it87 > drivers which are typically built as loadable modules. All the it87 drivers > select IT87_LOCK to compile the lock into the kernel. > The routines accessing the hardware are being called from module init, > open, ioctl and module exit routines and hence it is sufficient to use > calls to spin_lock and spin_unlock to acquire and release the locks. For > the same reasons it87_wdt.c has extensive changes to remove calls to > spin_lock_irqsave and spin_unlock_irqrestore. The lock is now acquired > in superio_enter and released in superio_exit. This is now identical > to the code in drivers/hwmon/it87.c and drivers/watchdog/it8712f_wdt.c. > Added __acquire and __release annotations wherever needed. > --- > drivers/hwmon/Kconfig | 1 + > drivers/hwmon/it87.c | 14 ++++++++++++- > drivers/watchdog/Kconfig | 12 +++++++++++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/it8712f_wdt.c | 10 ++++---- > drivers/watchdog/it87_lock.c | 27 +++++++++++++++++++++++++ > drivers/watchdog/it87_wdt.c | 42 ++++++--------------------------------- > include/linux/it87_lock.h | 28 ++++++++++++++++++++++++++ > 8 files changed, 94 insertions(+), 41 deletions(-) > create mode 100644 drivers/watchdog/it87_lock.c > create mode 100644 include/linux/it87_lock.h > > Signed-off-by: Nat Gurumoorthy > Seems to me those should be separate patches, one per affected subsystem. Guenter -- 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/