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Tue, 28 Jul 2020 08:47:14 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id CA6F7C43395; Tue, 28 Jul 2020 08:47:14 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id 14F51C433C6; Tue, 28 Jul 2020 08:47:14 +0000 (UTC) MIME-Version: 1.0 Date: Tue, 28 Jul 2020 14:17:14 +0530 From: Sai Prakash Ranjan To: Stephen Boyd Subject: Re: [PATCHv2] coresight: etm4x: Fix etm4_count race by moving cpuhp callbacks to init In-Reply-To: <159592494608.1360974.13925720722764973592@swboyd.mtv.corp.google.com> References: <20200728075102.30807-1-saiprakash.ranjan@codeaurora.org> <159592494608.1360974.13925720722764973592@swboyd.mtv.corp.google.com> Message-ID: X-Sender: saiprakash.ranjan@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200728_044719_528782_B9CADE62 X-CRM114-Status: GOOD ( 22.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mathieu Poirier , Suzuki K Poulose , linux-arm-msm@vger.kernel.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mike Leach Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-07-28 13:59, Stephen Boyd wrote: > Quoting Sai Prakash Ranjan (2020-07-28 00:51:02) >> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c >> b/drivers/hwtracing/coresight/coresight-etm4x.c >> index 6d7d2169bfb2..adb71987a1e3 100644 >> --- a/drivers/hwtracing/coresight/coresight-etm4x.c >> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c >> @@ -48,8 +48,6 @@ module_param(pm_save_enable, int, 0444); >> MODULE_PARM_DESC(pm_save_enable, >> "Save/restore state on power down: 1 = never, 2 = >> self-hosted"); >> >> -/* The number of ETMv4 currently registered */ >> -static int etm4_count; >> static struct etmv4_drvdata *etmdrvdata[NR_CPUS]; >> static void etm4_set_default_config(struct etmv4_config *config); >> static int etm4_set_event_filters(struct etmv4_drvdata *drvdata, >> @@ -1403,12 +1401,9 @@ static int etm4_pm_setup_cpuslocked(void) > > Is this only called from __init now? If so please mark it as __init > then. > Yes, will change it. >> { >> int ret; >> >> - if (etm4_count++) >> - return 0; >> - >> ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb); >> if (ret) >> - goto reduce_count; >> + return ret; >> >> ret = >> cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING, >> >> "arm/coresight4:starting", >> @@ -1432,17 +1427,11 @@ static int etm4_pm_setup_cpuslocked(void) >> >> unregister_notifier: >> cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); >> - >> -reduce_count: >> - --etm4_count; >> return ret; >> } >> >> static void etm4_pm_clear(void) > > This is __init too? > Will change. >> { >> - if (--etm4_count != 0) >> - return; >> - >> cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); >> cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); >> if (hp_online) { >> @@ -1598,4 +1576,29 @@ static struct amba_driver etm4x_driver = { >> .probe = etm4_probe, >> .id_table = etm4_ids, >> }; >> -builtin_amba_driver(etm4x_driver); >> + >> +static int __init etm4x_init(void) >> +{ >> + int ret; >> + >> + cpus_read_lock(); >> + ret = etm4_pm_setup_cpuslocked(); >> + cpus_read_unlock(); >> + >> + /* etm4_pm_setup_cpuslocked() does its own cleanup - exit on >> error */ >> + if (ret) >> + return ret; >> + >> + ret = amba_driver_register(&etm4x_driver); >> + if (ret) { >> + pr_info("Error registering etm4x driver\n"); > > Use pr_err() please. > Yes indeed, will change. >> + goto err_init; >> + } >> + >> + return ret; >> + >> +err_init: > > Why is this a goto? > >> + etm4_pm_clear(); >> + return ret; > > Instead of just putting this in the if (ret) arm? > Will change. >> +} >> +module_init(etm4x_init); > > It was device_initcall before with builtin_amba_driver(), best to not > change that. Sure. I will wait to see if there are any more comments on this patch and then post a v3. Thanks for the review Stephen. Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel