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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 75A50C4338F for ; Sun, 15 Aug 2021 20:21:35 +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 3CAAF6120E for ; Sun, 15 Aug 2021 20:21:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3CAAF6120E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3DF5189192; Sun, 15 Aug 2021 20:21:32 +0000 (UTC) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2E8A789C08 for ; Sun, 15 Aug 2021 20:21:22 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10077"; a="276792973" X-IronPort-AV: E=Sophos;i="5.84,324,1620716400"; d="scan'208";a="276792973" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2021 13:21:19 -0700 X-IronPort-AV: E=Sophos;i="5.84,324,1620716400"; d="scan'208";a="461849483" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2021 13:21:19 -0700 From: Matthew Brost To: , drmdevel@freedesktop.org Cc: Date: Sun, 15 Aug 2021 13:15:53 -0700 Message-Id: <20210815201559.1150-16-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210815201559.1150-1-matthew.brost@intel.com> References: <20210815201559.1150-1-matthew.brost@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Intel-gfx] [PATCH 15/21] drm/i915/guc: Release submit fence from an IRQ X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" A subsequent patch will flip the locking hierarchy from ce->guc_state.lock -> sched_engine->lock to sched_engine->lock -> ce->guc_state.lock. As such we need to release the submit fence for a request from an IRQ to break a lock inversion - i.e. the fence must be release went holding ce->guc_state.lock and the releasing of the can acquire sched_engine->lock. Signed-off-by: Matthew Brost --- drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 15 ++++++++++++++- drivers/gpu/drm/i915/i915_request.h | 5 +++++ 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 54c0914b21f3..b09be9b88cb3 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2016,6 +2016,14 @@ static const struct intel_context_ops guc_context_ops = { .create_virtual = guc_create_virtual, }; +static void submit_work_cb(struct irq_work *wrk) +{ + struct i915_request *rq = container_of(wrk, typeof(*rq), submit_work); + + might_lock(&rq->engine->sched_engine->lock); + i915_sw_fence_complete(&rq->submit); +} + static void __guc_signal_context_fence(struct intel_context *ce) { struct i915_request *rq; @@ -2025,8 +2033,12 @@ static void __guc_signal_context_fence(struct intel_context *ce) if (!list_empty(&ce->guc_state.fences)) trace_intel_context_fence_release(ce); + /* + * Use an IRQ to ensure locking order of sched_engine->lock -> + * ce->guc_state.lock is preserved. + */ list_for_each_entry(rq, &ce->guc_state.fences, guc_fence_link) - i915_sw_fence_complete(&rq->submit); + irq_work_queue(&rq->submit_work); INIT_LIST_HEAD(&ce->guc_state.fences); } @@ -2136,6 +2148,7 @@ static int guc_request_alloc(struct i915_request *rq) spin_lock_irqsave(&ce->guc_state.lock, flags); if (context_wait_for_deregister_to_register(ce) || context_pending_disable(ce)) { + init_irq_work(&rq->submit_work, submit_work_cb); i915_sw_fence_await(&rq->submit); list_add_tail(&rq->guc_fence_link, &ce->guc_state.fences); diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h index 1bc1349ba3c2..d818cfbfc41d 100644 --- a/drivers/gpu/drm/i915/i915_request.h +++ b/drivers/gpu/drm/i915/i915_request.h @@ -218,6 +218,11 @@ struct i915_request { }; struct llist_head execute_cb; struct i915_sw_fence semaphore; + /** + * @submit_work: complete submit fence from an IRQ if needed for + * locking hierarchy reasons. + */ + struct irq_work submit_work; /* * A list of everyone we wait upon, and everyone who waits upon us. -- 2.32.0