From patchwork Wed Nov 24 18:03:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 517417 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0508FC4332F for ; Wed, 24 Nov 2021 18:03:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350312AbhKXSGq (ORCPT ); Wed, 24 Nov 2021 13:06:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:56366 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350227AbhKXSGi (ORCPT ); Wed, 24 Nov 2021 13:06:38 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BE0A061052; Wed, 24 Nov 2021 18:03:28 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1mpwcB-0027vT-TN; Wed, 24 Nov 2021 13:03:27 -0500 Message-ID: <20211124180327.744571634@goodmis.org> User-Agent: quilt/0.66 Date: Wed, 24 Nov 2021 13:03:12 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Daniel Wagner , Tom Zanussi , "Srivatsa S. Bhat" , Clark Williams , Maarten Lankhorst Subject: [PATCH RT 09/13] drm/i915/gt: Queue and wait for the irq_work item. References: <20211124180303.574562279@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org 5.10.78-rt56-rc3 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior Disabling interrupts and invoking the irq_work function directly breaks on PREEMPT_RT. PREEMPT_RT does not invoke all irq_work from hardirq context because some of the user have spinlock_t locking in the callback function. These locks are then turned into a sleeping locks which can not be acquired with disabled interrupts. Using irq_work_queue() has the benefit that the irqwork will be invoked in the regular context. In general there is "no" delay between enqueuing the callback and its invocation because the interrupt is raised right away on architectures which support it (which includes x86). Use irq_work_queue() + irq_work_sync() instead invoking the callback directly. Reported-by: Clark Williams Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Maarten Lankhorst Signed-off-by: Steven Rostedt (VMware) --- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c index 0040b4765a54..3f4f854786f2 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -342,10 +342,9 @@ void intel_breadcrumbs_park(struct intel_breadcrumbs *b) /* Kick the work once more to drain the signalers */ irq_work_sync(&b->irq_work); while (unlikely(READ_ONCE(b->irq_armed))) { - local_irq_disable(); - signal_irq_work(&b->irq_work); - local_irq_enable(); + irq_work_queue(&b->irq_work); cond_resched(); + irq_work_sync(&b->irq_work); } GEM_BUG_ON(!list_empty(&b->signalers)); }