From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5B26C0650E for ; Mon, 1 Jul 2019 18:23:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBB2E2184B for ; Mon, 1 Jul 2019 18:23:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NPoQA7t5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726714AbfGASXQ (ORCPT ); Mon, 1 Jul 2019 14:23:16 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:44248 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726563AbfGASXP (ORCPT ); Mon, 1 Jul 2019 14:23:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=2+u+Cc7eowehJoJEy3M8QpwEakJMHDd3AEighBeayWY=; b=NPoQA7t5AwxU+LhTLu2gWOG+9 6/iAbCCWhaBJp83HLnSZrB6YVFr+/gHxsiFe0Zl+vUuyrj9VXYKOEiszM7ojN8e0DtWa43CEdaw4X JZPaZAM6xO/fjuZGaGrZyGPFRaNjrNAf0/HGEEz3QWliceTYj3LEhtPlVmaOZaX0G9zRgQswGpLLg KWL7hKvXZOTeFln1iJ5oBkuVuAelhFJvqA3IRQC7qVHipPMbBcmX8KvmlnxVOtBWqeMhnhi74k1xc d+0oqYSUxukHcM77RJP8oA2zGGAjRZzn2ftQ4EFulTW0JSMIlzGoXHXXwNRXMBdv69TBszWhwcQZ1 dhgDTng1A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hi0xN-0000Tu-BP; Mon, 01 Jul 2019 18:23:13 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3472E20A31C67; Mon, 1 Jul 2019 20:23:11 +0200 (CEST) Date: Mon, 1 Jul 2019 20:23:11 +0200 From: Peter Zijlstra To: Thomas Gleixner Cc: LKML , x86@kernel.org, Marc Zyngier Subject: Re: [patch V2 2/6] genirq: Fix misleading synchronize_irq() documentation Message-ID: <20190701182311.GV3419@hirez.programming.kicks-ass.net> References: <20190628111148.828731433@linutronix.de> <20190628111440.189241552@linutronix.de> <20190701145340.GB3402@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 01, 2019 at 08:01:24PM +0200, Thomas Gleixner wrote: > On Mon, 1 Jul 2019, Peter Zijlstra wrote: > > > On Fri, Jun 28, 2019 at 01:11:50PM +0200, Thomas Gleixner wrote: > > > The function might sleep, so it cannot be called from interrupt > > > context. Not even with care. > > > > > > Signed-off-by: Thomas Gleixner > > > --- > > > kernel/irq/manage.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > --- a/kernel/irq/manage.c > > > +++ b/kernel/irq/manage.c > > > @@ -96,7 +96,8 @@ EXPORT_SYMBOL(synchronize_hardirq); > > > * to complete before returning. If you use this function while > > > * holding a resource the IRQ handler may need you will deadlock. > > > * > > > - * This function may be called - with care - from IRQ context. > > > + * Can only be called from preemptible code as it might sleep when > > > + * an interrupt thread is associated to @irq. > > > */ > > > void synchronize_irq(unsigned int irq) > > > { > > > > + might_sleep(); > > > > ? > > .... > > wait_event() > might_sleep() ... > That's conditional on desc, but sure, that should work in most sane cases.