linux-kernel - Re: [PATCH] media: ipu3: don't use recursion at the Kernel

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Message-ID: <YajBJ8W8e6UdDrcU@paasikivi.fi.intel.com>
Date:   Thu, 2 Dec 2021 14:50:47 +0200
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Bingbu Cao <bingbu.cao@...el.com>,
        Dan Scally <djrscally@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tianshu Qiu <tian.shu.qiu@...el.com>,
        Yong Zhi <yong.zhi@...el.com>, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: Re: [PATCH] media: ipu3: don't use recursion at the Kernel

Hi Mauro,

On Thu, Dec 02, 2021 at 12:44:26PM +0100, Mauro Carvalho Chehab wrote:
> The Kernel stack is too small. Doing recursions there is a very
> bad idea, as, if something gets wrong, it could lead to data
> corruption. So, re-implement cio2_check_fwnode_graph() to avoid
> recursion.

Any decent compiler should be able to optimise out tail recursion.

But is checking the secondary pointer even needed these days?
fwnode_graph_get_next_endpoint() does that already, it's not something
drivers should be required to do.

-- 
Kind regards,

Sakari Ailus