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[2620:137:e000::1:20]) by mx.google.com with ESMTP id bm18-20020a656e92000000b004fb97a4c536si1868574pgb.873.2023.03.14.03.39.03; Tue, 14 Mar 2023 03:39:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231400AbjCNKgW (ORCPT + 99 others); Tue, 14 Mar 2023 06:36:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231226AbjCNKgH (ORCPT ); Tue, 14 Mar 2023 06:36:07 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9512830B20; Tue, 14 Mar 2023 03:35:18 -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 4C119169E; Tue, 14 Mar 2023 03:35:19 -0700 (PDT) Received: from e123648.arm.com (unknown [10.57.19.101]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C03C63F71A; Tue, 14 Mar 2023 03:34:32 -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 07/17] PM: EM: Check if the get_cost() callback is present in em_compute_costs() Date: Tue, 14 Mar 2023 10:33:47 +0000 Message-Id: <20230314103357.26010-8-lukasz.luba@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230314103357.26010-1-lukasz.luba@arm.com> References: <20230314103357.26010-1-lukasz.luba@arm.com> X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760339276939121282?= X-GMAIL-MSGID: =?utf-8?q?1760339276939121282?= 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 3b778743ba89..230310709e2a 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -122,7 +122,7 @@ 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",