From patchwork Thu Oct 10 16:06:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 11184883 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 682F914DB for ; Fri, 11 Oct 2019 06:48:35 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5053E214E0 for ; Fri, 11 Oct 2019 06:48:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5053E214E0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7AE916EBA4; Fri, 11 Oct 2019 06:48:22 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 580306E030; Thu, 10 Oct 2019 16:06:48 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=flow.W.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1iIaxh-00056C-2N; Thu, 10 Oct 2019 18:06:45 +0200 From: Sebastian Andrzej Siewior To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Subject: [PATCH] drm/i915: Don't disable interrupts independently of the lock Date: Thu, 10 Oct 2019 18:06:40 +0200 Message-Id: <20191010160640.6472-1-bigeasy@linutronix.de> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 X-Mailman-Approved-At: Fri, 11 Oct 2019 06:48:21 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , Sebastian Andrzej Siewior , Rodrigo Vivi , tglx@linutronix.de Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The locks (active.lock and rq->lock) need to be taken with disabled interrupts. This is done in i915_request_retire() by disabling the interrupts independently of the locks itself. While local_irq_disable()+spin_lock() equals spin_lock_irq() on vanilla it does not on PREEMPT_RT. Also, it is not obvious if there is a special reason to why the interrupts are disabled independently of the lock. Enable/disable interrupts as part of the locking instruction. Signed-off-by: Sebastian Andrzej Siewior --- drivers/gpu/drm/i915/i915_request.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -251,15 +251,13 @@ static bool i915_request_retire(struct i active->retire(active, rq); } - local_irq_disable(); - /* * We only loosely track inflight requests across preemption, * and so we may find ourselves attempting to retire a _completed_ * request that we have removed from the HW and put back on a run * queue. */ - spin_lock(&rq->engine->active.lock); + spin_lock_irq(&rq->engine->active.lock); list_del(&rq->sched.link); spin_unlock(&rq->engine->active.lock); @@ -278,9 +276,7 @@ static bool i915_request_retire(struct i __notify_execute_cb(rq); } GEM_BUG_ON(!list_empty(&rq->execute_cb)); - spin_unlock(&rq->lock); - - local_irq_enable(); + spin_unlock_irq(&rq->lock); remove_from_client(rq); list_del(&rq->link);