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Date:   Fri, 20 Dec 2019 11:04:26 -0800
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, okukatla@codeaurora.org,
        jcrouse@codeaurora.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] interconnect: Check for valid path in icc_set_bw()
Message-ID: <20191220190426.GE549437@yoga>
References: <20191220171310.24169-1-georgi.djakov@linaro.org>
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On Fri 20 Dec 09:13 PST 2019, Georgi Djakov wrote:

> Use IS_ERR() to ensure that the path passed to icc_set_bw() is valid.
> 
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
>  drivers/interconnect/core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
> index 63c164264b73..14a6f7ade44a 100644
> --- a/drivers/interconnect/core.c
> +++ b/drivers/interconnect/core.c
> @@ -498,6 +498,11 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
>  	if (!path || !path->num_nodes)
>  		return 0;
>  
> +	if (IS_ERR(path)) {

This is a sign of a logical error, and the print is likely to be
ignored/lost in the noise. So I think the response should aid to help
the developer hitting this to resolve the issue.

So I think this is more visible and more useful as:

	if (WARN_ON(IS_ERR(path)))
		return -EINVAL;


PS. Doesn't path->num_nodes == 0 fall in this category as well? When
would you have a path object with no nodes passed to this function?

Regards,
Bjorn

> +		pr_err("%s: invalid path=%ld\n", __func__, PTR_ERR(path));
> +		return -EINVAL;
> +	}
> +
>  	mutex_lock(&icc_lock);
>  
>  	old_avg = path->reqs[0].avg_bw;