Re: [patch] drm/msm/dsi: free first element on error

From: Jani Nikula <jani.nikula@linux.intel.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
	Rob Clark <robdclark@gmail.com>,
	Archit Taneja <architt@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org,
	Wei Yongjun <yongjun_wei@trendmicro.com.cn>,
	freedreno@lists.freedesktop.org, kernel-janitors@vger.kernel.org,
	dri-devel@lists.freedesktop.org
Subject: Re: [patch] drm/msm/dsi: free first element on error
Date: Thu, 16 Feb 2017 11:27:47 +0000	[thread overview]
Message-ID: <87a89mnznw.fsf@intel.com> (raw)
In-Reply-To: <20170216105042.GA25544@mwanda>

On Thu, 16 Feb 2017, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> We want to free msm_host->bus_clks[0] so the > should be >=.
>
> Fixes: 6e0eb52eba9e ("drm/msm/dsi: Parse bus clocks from a list")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 1fc07ce24686..239e79b39a45 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -437,7 +437,7 @@ static int dsi_bus_clk_enable(struct msm_dsi_host *msm_host)
>  
>  	return 0;
>  err:
> -	for (; i > 0; i--)
> +	for (; i >= 0; i--)
>  		clk_disable_unprepare(msm_host->bus_clks[i]);

By the looks of it this is also wrong. I didn't look at the functions,
but you probably don't want to unprepare something where prepare failed,
i.e. you want to -1 both the start and end offsets. Perhaps the right
fix is

	while (i--)
		clk_disable_unprepare(msm_host->bus_clks[i]);

which also seems to be widely used on error paths.

BR,
Jani.

>  
>  	return ret;
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-- 
Jani Nikula, Intel Open Source Technology Center