linux-kernel - Re: [PATCH v2] perf/imx_ddr: Fix cpu hotplug state cleanup

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Message-ID: <20200115124951.GG21692@willie-the-truck>
Date:   Wed, 15 Jan 2020 12:49:51 +0000
From:   Will Deacon <will@...nel.org>
To:     Leonard Crestez <leonard.crestez@....com>
Cc:     Joakim Zhang <qiangqing.zhang@....com>,
        Frank Li <frank.li@....com>,
        Mark Rutland <mark.rutland@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] perf/imx_ddr: Fix cpu hotplug state cleanup

On Tue, Jan 14, 2020 at 10:25:46PM +0200, Leonard Crestez wrote:
> This driver allocates a dynamic cpu hotplug state but never releases it.
> If reloaded in a loop it will quickly trigger a WARN message:
> 
> 	"No more dynamic states available for CPU hotplug"
> 
> Fix by calling cpuhp_remove_multi_state on remove like several other
> perf pmu drivers.
> 
> Also fix the cleanup logic on probe error paths: add the missing
> cpuhp_remove_multi_state call and properly check the return value from
> cpuhp_state_add_instant_nocalls.
> 
> Fixes: 9a66d36cc7ac ("drivers/perf: imx_ddr: Add DDR performance counter support to perf")
> Signed-off-by: Leonard Crestez <leonard.crestez@....com>
> 
> ---
> 
> Changes since v1:
> * Handle cpuhp_state_add_instant_nocalls error with additional error
> labels.
> Link to v1: https://patchwork.kernel.org/patch/11302423/
> ---
>  drivers/perf/fsl_imx8_ddr_perf.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)

Thanks, I've queued this up with Joakim's ack.

Will