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Date:   Fri, 18 Oct 2019 09:49:01 -0700
From:   Bjorn Andersson <bjorn.andersson@linaro.org>
To:     Georgi Djakov <georgi.djakov@linaro.org>
Cc:     linux-pm@vger.kernel.org, evgreen@chromium.org,
        daidavid1@codeaurora.org, vincent.guittot@linaro.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] interconnect: Add locking in icc_set_tag()
Message-ID: <20191018164901.GC1669@tuxbook-pro>
References: <20191018141750.17032-1-georgi.djakov@linaro.org>
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On Fri 18 Oct 07:17 PDT 2019, Georgi Djakov wrote:

> We must ensure that the tag is not changed while we aggregate the
> requests. Currently the icc_set_tag() is not using any locks and this
> may cause the values to be aggregated incorrectly. Fix this by acquiring
> the icc_lock while we set the tag.
> 
> Fixes: 127ab2cc5f19 ("interconnect: Add support for path tags")
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> ---
>  drivers/interconnect/core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
> index e24092558c29..4940c0741d40 100644
> --- a/drivers/interconnect/core.c
> +++ b/drivers/interconnect/core.c
> @@ -408,8 +408,12 @@ void icc_set_tag(struct icc_path *path, u32 tag)
>  	if (!path)
>  		return;
>  
> +	mutex_lock(&icc_lock);
> +
>  	for (i = 0; i < path->num_nodes; i++)
>  		path->reqs[i].tag = tag;
> +
> +	mutex_unlock(&icc_lock);
>  }
>  EXPORT_SYMBOL_GPL(icc_set_tag);
>