linux-kernel - Re: [PATCH v2] drm/etnaviv: fix ref count leak via pm_runtime_get

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Date:   Mon, 15 Jun 2020 17:57:38 +0200
From:   Markus Elfring <Markus.Elfring@....de>
To:     Navid Emamdoost <navid.emamdoost@...il.com>,
        dri-devel@...ts.freedesktop.org, etnaviv@...ts.freedesktop.org,
        linux+etnaviv@...linux.org.uk
Cc:     Navid Emamdoost <emamd001@....edu>, Kangjie Lu <kjlu@....edu>,
        Stephen McCamant <mccamant@...umn.edu>,
        Qiushi Wu <wu000273@....edu>, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Christian Gmeiner <christian.gmeiner@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Lucas Stach <l.stach@...gutronix.de>
Subject: Re: [PATCH v2] drm/etnaviv: fix ref count leak via
 pm_runtime_get_sync

…
> In case of failure, decrement the ref count before returning.

Can it be nicer to use the term “reference count” here?

Will the tag “Fixes” become helpful for the commit message?


…
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
…
> @@ -1326,6 +1331,7 @@  struct dma_fence *etnaviv_gpu_submit(struct etnaviv_gem_submit *submit)
>  	ret = event_alloc(gpu, nr_events, event);
>  	if (ret) {
>  		DRM_ERROR("no free events\n");
> +		pm_runtime_put_noidle(gpu->dev);
>  		return NULL;
>  	}

I suggest to move a bit of exception handling code to the end of
this function implementation so that it can be better reused after
the addition of a jump target like “put_runtime”.

Regards,
Markus