Re: [PATCH AUTOSEL 5.16 24/30] dmaengine: shdma: Fix runtime PM imbalance on error

刘永志
2022-02-25T06:25:54Z

> -----原始邮件-----
> 发件人: "Pavel Machek" <pavel@denx.de>
> 发送时间: 2022-02-25 06:39:08 (星期五)
> 收件人: "Sasha Levin" <sashal@kernel.org>
> 抄送: linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Yongzhi Liu" <lyz_cs@pku.edu.cn>, "Vinod Koul" <vkoul@kernel.org>, christophe.jaillet@wanadoo.fr, arnd@arndb.de, laurent.pinchart@ideasonboard.com, dmaengine@vger.kernel.org
> 主题: Re: [PATCH AUTOSEL 5.16 24/30] dmaengine: shdma: Fix runtime PM imbalance on error
>
> Hi!
>
> > From: Yongzhi Liu <lyz_cs@pku.edu.cn>
> >
> > [ Upstream commit 455896c53d5b803733ddd84e1bf8a430644439b6 ]
> >
> > pm_runtime_get_() increments the runtime PM usage counter even
> > when it returns an error code, thus a matching decrement is needed on
> > the error handling path to keep the counter balanced.
>
> I don't think that's right.
>
> Notice that -ret is ignored (checked 4.4 and 5.10), so we don't
> actually abort/return error; we just printk. We'll do two
> pm_runtime_put's after the "fix".

Thank you very much for the correction. I am very sorry that I caused you unnecessary trouble because of my carelessness.
The pm_runtime_put is indeed called later in __ld_cleanup, so only printk is needed at -ret and the patch is not right.

>
> Please drop from -stable.
>
> Best regards,
> Pavel
> --
> DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany