linux-kernel - Re: [PATCH v4 1/2] clk: hisilicon: Use correct return value about hisi_reset

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Message-ID: <159070775347.69627.5841986835404441281@swboyd.mtv.corp.google.com>
Date:   Thu, 28 May 2020 16:15:53 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Xuefeng Li <lixuefeng@...ngson.cn>
Subject: Re: [PATCH v4 1/2] clk: hisilicon: Use correct return value about hisi_reset_init()

Quoting Tiezhu Yang (2020-05-27 19:27:42)
> On 05/28/2020 03:06 AM, Stephen Boyd wrote:
> > Quoting Tiezhu Yang (2020-05-27 07:39:21)
> >> The return value about hisi_reset_init() is not correct, fix it.
> >>
> >> Fixes: e9a2310fb689 ("reset: hisilicon: fix potential NULL pointer dereference")
> > hisi_reset_init() returns NULL on error in that commit. This patch
> > doesn't make sense.
> 
> Hi Stephen,
> 
> The initial aim of this patch is to use correct return value about
> hisi_reset_init(), maybe NULL is OK, but the return value in this
> patch is more accurate.

The implementation of hisi_reset_init() that I see is this:


	struct hisi_reset_controller *rstc;

	rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL);
	if (!rstc)
		return NULL;

	rstc->membase = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(rstc->membase))
		return NULL;

	spin_lock_init(&rstc->lock);
	rstc->rcdev.owner = THIS_MODULE;
	rstc->rcdev.ops = &hisi_reset_ops;
	rstc->rcdev.of_node = pdev->dev.of_node;
	rstc->rcdev.of_reset_n_cells = 2;
	rstc->rcdev.of_xlate = hisi_reset_of_xlate;
	reset_controller_register(&rstc->rcdev);

	return rstc;

And that returns NULL on an error and a valid pointer on success.
Changing the code to check the return value of hisi_reset_init() for an
error pointer is simply wrong without updating hisi_reset_init() to
return an error pointer on error. Where is the patch that changes
hisi_reset_init() to return an error pointer?