From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [PATCH v2 7/9] gpio: 104-idi-48: make use of raw_spinlock variants Date: Tue, 28 Mar 2017 11:11:59 +0200 Message-ID: References: <20170322124414.GA22323@sophia> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-it0-f42.google.com ([209.85.214.42]:38437 "EHLO mail-it0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754677AbdC1JMB (ORCPT ); Tue, 28 Mar 2017 05:12:01 -0400 Received: by mail-it0-f42.google.com with SMTP id y18so11507640itc.1 for ; Tue, 28 Mar 2017 02:12:00 -0700 (PDT) In-Reply-To: <20170322124414.GA22323@sophia> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org 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" 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