Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754888AbdC1JMD (ORCPT ); Tue, 28 Mar 2017 05:12:03 -0400 Received: from mail-it0-f49.google.com ([209.85.214.49]:37704 "EHLO mail-it0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754722AbdC1JMB (ORCPT ); Tue, 28 Mar 2017 05:12:01 -0400 MIME-Version: 1.0 In-Reply-To: <20170322124414.GA22323@sophia> References: <20170322124414.GA22323@sophia> From: Linus Walleij Date: Tue, 28 Mar 2017 11:11:59 +0200 Message-ID: Subject: Re: [PATCH v2 7/9] gpio: 104-idi-48: make use of raw_spinlock variants To: William Breathitt Gray Cc: Julia Cartwright , Alexandre Courbot , "linux-kernel@vger.kernel.org" , linux-rt-users@vger.kernel.org, "linux-gpio@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 974 Lines: 23 On Wed, Mar 22, 2017 at 1:44 PM, William Breathitt Gray wrote: > On Tue, Mar 21, 2017 at 05:43:07PM -0500, Julia Cartwright wrote: >>The 104-idi-48 gpio driver currently implements an irq_chip for handling >>interrupts; due to how irq_chip handling is done, it's necessary for the >>irq_chip methods to be invoked from hardirq context, even on a a >>real-time kernel. Because the spinlock_t type becomes a "sleeping" >>spinlock w/ RT kernels, it is not suitable to be used with irq_chips. >> >>A quick audit of the operations under the lock reveal that they do only >>minimal, bounded work, and are therefore safe to do under a raw spinlock. >> >>Signed-off-by: Julia Cartwright > > Hi Julia, > > This driver also uses a second spinlock_t, called ack_lock, to prevent > reentrance into the idi_48_irq_handler function. Should ack_lock also be > implemented as a raw_spinlock_t? Hm, can I apply this one patch or not? Linus Walleij