From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753044Ab1HISyD (ORCPT ); Tue, 9 Aug 2011 14:54:03 -0400 Received: from www.hansjkoch.de ([178.63.77.200]:54440 "EHLO www.hansjkoch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751484Ab1HISyB (ORCPT ); Tue, 9 Aug 2011 14:54:01 -0400 Date: Tue, 9 Aug 2011 20:53:41 +0200 From: "Hans J. Koch" To: "Michael S. Tsirkin" Cc: "Hans J. Koch" , Sebastian Andrzej Siewior , Chris Wright , Jesse Barnes , Greg Kroah-Hartman , Anthony Foiani , linux-kernel@vger.kernel.org Subject: Re: [PATCH] uio/gen-pci: don't enable interrupts in ISR Message-ID: <20110809185341.GD4229@local> References: <20110804204606.GA19724@linutronix.de> <20110804210413.GA29222@redhat.com> <20110805001507.GA5987@local> <20110808062431.GB5182@redhat.com> <20110808171931.GB867@local> <20110809113743.GA32299@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110809113743.GA32299@redhat.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 On Tue, Aug 09, 2011 at 02:37:43PM +0300, Michael S. Tsirkin wrote: > > > > Should I hack up a patch to remove the lock, or do you have anything in your > > pipeline? > > > Please do. > Here it is: Greg (and anyone else...), you can also pull this from branch "uio-for-greg" from git://hansjkoch.de/git/linux-hjk >>From ff74627ade002d40fe1f902b7aadab8b1f15f889 Mon Sep 17 00:00:00 2001 From: "Hans J. Koch" Date: Tue, 9 Aug 2011 20:34:31 +0200 Subject: [PATCH] uio: uio_pci_generic: Remove useless spin_lock The spin_lock in uio_pci_generic.c is only used in the interrupt handler, which cannot be executed twice at the same time. That makes the lock rather pointless. This patch removes it. Cc: "Michael S. Tsirkin" Cc: Chris Wright Cc: Jesse Barnes Cc: Sebastian Andrzej Siewior Cc: Anthony Foiani Reported-by: Anthony Foiani Reported-by: Sebastian Andrzej Siewior Signed-off-by: Hans J. Koch --- drivers/uio/uio_pci_generic.c | 5 ----- 1 files changed, 0 insertions(+), 5 deletions(-) diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c index fc22e1e..02bd47b 100644 --- a/drivers/uio/uio_pci_generic.c +++ b/drivers/uio/uio_pci_generic.c @@ -24,7 +24,6 @@ #include #include #include -#include #define DRIVER_VERSION "0.01.0" #define DRIVER_AUTHOR "Michael S. Tsirkin " @@ -33,7 +32,6 @@ struct uio_pci_generic_dev { struct uio_info info; struct pci_dev *pdev; - spinlock_t lock; /* guards command register accesses */ }; static inline struct uio_pci_generic_dev * @@ -57,7 +55,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info) BUILD_BUG_ON(PCI_COMMAND % 4); BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS); - spin_lock_irq(&gdev->lock); pci_block_user_cfg_access(pdev); /* Read both command and status registers in a single 32-bit operation. @@ -83,7 +80,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info) done: pci_unblock_user_cfg_access(pdev); - spin_unlock_irq(&gdev->lock); return ret; } @@ -158,7 +154,6 @@ static int __devinit probe(struct pci_dev *pdev, gdev->info.irq_flags = IRQF_SHARED; gdev->info.handler = irqhandler; gdev->pdev = pdev; - spin_lock_init(&gdev->lock); if (uio_register_device(&pdev->dev, &gdev->info)) goto err_register; -- 1.7.5.4