From patchwork Thu Aug 26 03:23:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Brost X-Patchwork-Id: 12458987 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,URIBL_BLOCKED,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 309DEC4320E for ; Thu, 26 Aug 2021 03:29:46 +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 01F5261008 for ; Thu, 26 Aug 2021 03:29:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 01F5261008 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 5D6016E512; Thu, 26 Aug 2021 03:28:59 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id A15A96E4DE; Thu, 26 Aug 2021 03:28:42 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="215811077" X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="215811077" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:40 -0700 X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="684738570" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:39 -0700 From: Matthew Brost To: , Cc: Date: Wed, 25 Aug 2021 20:23:18 -0700 Message-Id: <20210826032327.18078-19-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210826032327.18078-1-matthew.brost@intel.com> References: <20210826032327.18078-1-matthew.brost@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 18/27] drm/i915/guc: Release submit fence from an irq_work 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. v2: (Daniele) - Delete request from list before calling irq_work_queue Reviewed-by: Daniele Ceraolo Spurio Signed-off-by: Matthew Brost --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 22 ++++++++++++++++--- drivers/gpu/drm/i915/i915_request.h | 5 +++++ 2 files changed, 24 insertions(+), 3 deletions(-) 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 baf789f37d42..c86aae0899e5 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -2035,17 +2035,32 @@ 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; + struct i915_request *rq, *rn; lockdep_assert_held(&ce->guc_state.lock); if (!list_empty(&ce->guc_state.fences)) trace_intel_context_fence_release(ce); - list_for_each_entry(rq, &ce->guc_state.fences, guc_fence_link) - i915_sw_fence_complete(&rq->submit); + /* + * Use an IRQ to ensure locking order of sched_engine->lock -> + * ce->guc_state.lock is preserved. + */ + list_for_each_entry_safe(rq, rn, &ce->guc_state.fences, + guc_fence_link) { + list_del(&rq->guc_fence_link); + irq_work_queue(&rq->submit_work); + } INIT_LIST_HEAD(&ce->guc_state.fences); } @@ -2155,6 +2170,7 @@ 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.