Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755364Ab1F0Ws7 (ORCPT ); Mon, 27 Jun 2011 18:48:59 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:62257 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754456Ab1F0WrZ (ORCPT ); Mon, 27 Jun 2011 18:47:25 -0400 Date: Mon, 27 Jun 2011 16:47:22 -0600 From: Grant Likely To: Alexander Stein Cc: linux-kernel@vger.kernel.org, Tomoya MORINAGA Subject: Re: [PATCH] pch_gpio: transform mutex into spinlock Message-ID: <20110627224722.GG20865@ponder.secretlab.ca> References: <1308665847-13924-1-git-send-email-alexander.stein@systec-electronic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1308665847-13924-1-git-send-email-alexander.stein@systec-electronic.com> 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 Content-Length: 3405 Lines: 102 On Tue, Jun 21, 2011 at 04:17:27PM +0200, Alexander Stein wrote: > gpio_chip.can_sleep is 0, but gpio_set_value & friends lock a mutex. Thus > those functions are not callable from interrupt context. > Changing mutex into spinlock. > > Signed-off-by: Alexander Stein Tomoya, what do you think of this patch? > --- > I just noticed that the patch introduced at > http://marc.info/?l=linux-kernel&m=130863151431202&w=2 > also added a spinlock. I think those two spinlock can be merged into one. > > drivers/gpio/pch_gpio.c | 19 +++++++++++-------- > 1 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpio/pch_gpio.c b/drivers/gpio/pch_gpio.c > index 36919e7..262c200 100644 > --- a/drivers/gpio/pch_gpio.c > +++ b/drivers/gpio/pch_gpio.c > @@ -62,15 +62,16 @@ struct pch_gpio { > struct device *dev; > struct gpio_chip gpio; > struct pch_gpio_reg_data pch_gpio_reg; > - struct mutex lock; > + struct spinlock lock; > }; > > static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val) > { > u32 reg_val; > + unsigned long flags; > struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio); > > - mutex_lock(&chip->lock); > + spin_lock_irqsave(&chip->lock, flags); > reg_val = ioread32(&chip->reg->po); > if (val) > reg_val |= (1 << nr); > @@ -78,7 +79,7 @@ static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val) > reg_val &= ~(1 << nr); > > iowrite32(reg_val, &chip->reg->po); > - mutex_unlock(&chip->lock); > + spin_unlock_irqrestore(&chip->lock, flags); > } > > static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr) > @@ -94,8 +95,9 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr, > struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio); > u32 pm; > u32 reg_val; > + unsigned long flags; > > - mutex_lock(&chip->lock); > + spin_lock_irqsave(&chip->lock, flags); > pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS; > pm |= (1 << nr); > iowrite32(pm, &chip->reg->pm); > @@ -107,7 +109,7 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr, > reg_val &= ~(1 << nr); > iowrite32(reg_val, &chip->reg->po); > > - mutex_unlock(&chip->lock); > + spin_unlock_irqrestore(&chip->lock, flags); > > return 0; > } > @@ -116,12 +118,13 @@ static int pch_gpio_direction_input(struct gpio_chip *gpio, unsigned nr) > { > struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio); > u32 pm; > + unsigned long flags; > > - mutex_lock(&chip->lock); > + spin_lock_irqsave(&chip->lock, flags); > pm = ioread32(&chip->reg->pm) & PCH_GPIO_ALL_PINS; /*bits 0-11*/ > pm &= ~(1 << nr); > iowrite32(pm, &chip->reg->pm); > - mutex_unlock(&chip->lock); > + spin_unlock_irqrestore(&chip->lock, flags); > > return 0; > } > @@ -194,7 +197,7 @@ static int __devinit pch_gpio_probe(struct pci_dev *pdev, > > chip->reg = chip->base; > pci_set_drvdata(pdev, chip); > - mutex_init(&chip->lock); > + spin_lock_init(&chip->lock); > pch_gpio_setup(chip); > ret = gpiochip_add(&chip->gpio); > if (ret) { > -- > 1.7.3.4 > -- 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/