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=-16.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 28DBCC433F5 for ; Tue, 14 Sep 2021 12:28:08 +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 E82B760F92 for ; Tue, 14 Sep 2021 12:28:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E82B760F92 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.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 95AF089E65; Tue, 14 Sep 2021 12:28:04 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0B4968916C; Tue, 14 Sep 2021 12:28:03 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10106"; a="285667596" X-IronPort-AV: E=Sophos;i="5.85,292,1624345200"; d="scan'208";a="285667596" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Sep 2021 05:28:02 -0700 X-IronPort-AV: E=Sophos;i="5.85,292,1624345200"; d="scan'208";a="432975337" Received: from ocascan-mobl.ger.corp.intel.com (HELO [10.213.234.116]) ([10.213.234.116]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Sep 2021 05:28:01 -0700 To: =?UTF-8?Q?Christian_K=c3=b6nig?= , linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org Cc: daniel@ffwll.ch, intel-gfx@lists.freedesktop.org References: <20210913131707.45639-1-christian.koenig@amd.com> <20210913131707.45639-19-christian.koenig@amd.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <46a40614-b448-7f2d-7b6b-0705c4277e2b@linux.intel.com> Date: Tue, 14 Sep 2021 13:27:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210913131707.45639-19-christian.koenig@amd.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Intel-gfx] [PATCH 18/26] drm/i915: use new iterator in i915_gem_object_last_write_engine 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" On 13/09/2021 14:16, Christian König wrote: > This is maybe even a fix since the RCU usage here looks incorrect. What you think is incorrect? Pointless extra rcu locking? Also, FWIW, I submitted a patch to remove this function altogether since its IMO pretty useless, just failed in getting anyone to ack it so far. Regards, Tvrtko > Signed-off-by: Christian König > --- > drivers/gpu/drm/i915/gem/i915_gem_object.h | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h > index e9eecebf5c9d..3343922af4d6 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h > +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h > @@ -500,16 +500,15 @@ static inline struct intel_engine_cs * > i915_gem_object_last_write_engine(struct drm_i915_gem_object *obj) > { > struct intel_engine_cs *engine = NULL; > + struct dma_resv_cursor cursor; > struct dma_fence *fence; > > - rcu_read_lock(); > - fence = dma_resv_get_excl_unlocked(obj->base.resv); > - rcu_read_unlock(); > - > - if (fence && dma_fence_is_i915(fence) && !dma_fence_is_signaled(fence)) > - engine = to_request(fence)->engine; > - dma_fence_put(fence); > - > + dma_resv_for_each_fence_unlocked(obj->base.resv, &cursor, false, > + fence) { > + if (fence && dma_fence_is_i915(fence) && > + !dma_fence_is_signaled(fence)) > + engine = to_request(fence)->engine; > + } > return engine; > } > >