From patchwork Fri May 12 09:57:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Luba X-Patchwork-Id: 681531 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 AD80DC77B7C for ; Fri, 12 May 2023 09:59:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240483AbjELJ7M (ORCPT ); Fri, 12 May 2023 05:59:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240522AbjELJ6t (ORCPT ); Fri, 12 May 2023 05:58:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D06E1100D9; Fri, 12 May 2023 02:58:18 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 342C71691; Fri, 12 May 2023 02:59:03 -0700 (PDT) Received: from e123648.arm.com (unknown [10.57.22.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id DF6843F5A1; Fri, 12 May 2023 02:58:15 -0700 (PDT) From: Lukasz Luba To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael@kernel.org Cc: lukasz.luba@arm.com, dietmar.eggemann@arm.com, rui.zhang@intel.com, amit.kucheria@verdurent.com, amit.kachhap@gmail.com, daniel.lezcano@linaro.org, viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz, Pierre.Gondois@arm.com, ionela.voinescu@arm.com, rostedt@goodmis.org, mhiramat@kernel.org Subject: [PATCH v2 07/17] PM: EM: Check if the get_cost() callback is present in em_compute_costs() Date: Fri, 12 May 2023 10:57:33 +0100 Message-Id: <20230512095743.3393563-8-lukasz.luba@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230512095743.3393563-1-lukasz.luba@arm.com> References: <20230512095743.3393563-1-lukasz.luba@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org The em_compute_cost() is going to be re-used in runtime modified EM code path. Thus, make sure that this common code is safe and won't try to use the NULL pointer. The former em_compute_cost() didn't have to care about runtime modification code path. The upcoming changes introduce such option, but with different callback. Those two paths which use get_cost() (during first EM registration) or update_power() (during runtime modification) need to be safely handled in em_compute_costs(). Signed-off-by: Lukasz Luba --- kernel/power/energy_model.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 61d349fec545..8866d217714e 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -119,7 +119,7 @@ static int em_compute_costs(struct device *dev, struct em_perf_state *table, for (i = nr_states - 1; i >= 0; i--) { unsigned long power_res, cost; - if (flags & EM_PERF_DOMAIN_ARTIFICIAL) { + if (flags & EM_PERF_DOMAIN_ARTIFICIAL && cb->get_cost) { ret = cb->get_cost(dev, table[i].frequency, &cost); if (ret || !cost || cost > EM_MAX_POWER) { dev_err(dev, "EM: invalid cost %lu %d\n",