Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230423053208.2348-1-yejunyan@hust.edu.cn>
In-Reply-To: <20230423053208.2348-1-yejunyan@hust.edu.cn>
From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Wed, 26 Apr 2023 22:44:28 +0200
Message-ID: <CACRpkdbDfAJOWzkvEgOdoOCMQAQ24mauWAeWXWgvBmyU3mi0FQ@mail.gmail.com>
Subject: Re: [PATCH v2] pci: controller: pci-ftpci100: Release the clock resources
To:     Junyan Ye <yejunyan@hust.edu.cn>
Cc:     christophe.jaillet@wanadoo.fr,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Wei Yongjun <weiyongjun1@huawei.com>,
        Andrew Murray <amurray@thegoodpenguin.co.uk>,
        hust-os-kernel-patches@googlegroups.com,
        Dongliang Mu <dzm91@hust.edu.cn>, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Sun, Apr 23, 2023 at 7:34=E2=80=AFAM Junyan Ye <yejunyan@hust.edu.cn> wr=
ote:

> Smatch reported:
> 1. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe()
> warn: 'clk' from clk_prepare_enable() not released on lines:
> 442,451,462,478,512,517.
> 2. drivers/pci/controller/pci-ftpci100.c:526 faraday_pci_probe()
> warn: 'p->bus_clk' from clk_prepare_enable() not released on lines:
> 451,462,478,512,517.
>
> The clock resource is obtained by the devm_clk_get function. The
> clk_prepare_enable function then makes the clock resource ready for use,
> notifying the system that the clock resource should be run. After that,
> the clock resource should be released when it is no longer needed. The
> corresponding function is clk_disable_unprepare. However, while doing
> some error handling in the faraday_pci_probe function, the
> clk_disable_unprepare function is not called to release the clk and
> p->bus_clk resources.
>
> Fix this warning by changing the devm_clk_get function to
> devm_clk_get_enabled, which is equivalent to
> devm_clk_get() + clk_prepare_enable(). And with the
> devm_clk_get_enabled function, the clock will automatically be
> disabled, unprepared and freed when the device is unbound from the bus.
>
> Fixes: b3c433efb8a3 ("PCI: faraday: Fix wrong pointer passed to PTR_ERR()=
")
> Fixes: 2eeb02b28579 ("PCI: faraday: Add clock handling")
> Fixes: 783a862563f7 ("PCI: faraday: Use pci_parse_request_of_pci_ranges()=
")
> Fixes: d3c68e0a7e34 ("PCI: faraday: Add Faraday Technology FTPCI100 PCI H=
ost Bridge driver")
> Fixes: f1e8bd21e39e ("PCI: faraday: Convert IRQ masking to raw PCI config=
 accessors")
> Signed-off-by: Junyan Ye <yejunyan@hust.edu.cn>
> Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
> ---
> v1 -> v2: Switch from clk_disable_unprepare() to devm_clk_get_enabled() t=
o release the clock.
> This issue is found by static analyzer.

Neat fix, saves codelines!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij