From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C380C47082 for ; Mon, 7 Jun 2021 08:06:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 617696102A for ; Mon, 7 Jun 2021 08:06:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230217AbhFGIIq (ORCPT ); Mon, 7 Jun 2021 04:08:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:59196 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbhFGIIn (ORCPT ); Mon, 7 Jun 2021 04:08:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5849D6102A; Mon, 7 Jun 2021 08:06:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623053212; bh=xmIDJ297EbDzxkQF9obeTuoyIAjOCtz2+6Ofw+DrFXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sM2u+WyfdldAkzzqhNEq2wVbktPE9gknkrkYPnr8/LdjYaKYBXHFiOr+U8NylodnI dKCe3oCN2qVP2hFpiTEofcH0Pq0cCumErxKYvFsJMlgjmNMABEE2OdTPsV2zfG8KZA r5hy6REuclAD4YTFgHZlkFFt2VpdPNzwM6wsdtfajESdm8taI/7o37jA+65CEvmp8y Y3SfrV4VpNVsJttuF/Fu93gt+mfN10rkDCg+YM1BV5Jho1oqoDXosVqcXuQ8HBmBhR 6+O4rcp61F7naUFa5GLuo6zPA7M0I7iKcn8mc/jVvLmTPOnFU7sAaFhRo+eFqHvdpZ hLfIiy8HB0bGg== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1lqAHU-0004Ne-KD; Mon, 07 Jun 2021 10:06:45 +0200 Date: Mon, 7 Jun 2021 10:06:44 +0200 From: Johan Hovold To: Vinod Koul Cc: "yukuai (C)" , mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, michal.simek@xilinx.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, yi.zhang@huawei.com Subject: Re: [PATCH 2/3] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Message-ID: References: <20210517081826.1564698-1-yukuai3@huawei.com> <20210517081826.1564698-3-yukuai3@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 03, 2021 at 04:39:08PM +0530, Vinod Koul wrote: > On 31-05-21, 11:19, Johan Hovold wrote: > > On Mon, May 31, 2021 at 02:27:34PM +0530, Vinod Koul wrote: > > > On 31-05-21, 14:11, yukuai (C) wrote: > > > > On 2021/05/31 12:00, Vinod Koul wrote: > > > > > On 17-05-21, 16:18, Yu Kuai wrote: > > > > > > pm_runtime_get_sync will increment pm usage counter even it failed. > > > > > > Forgetting to putting operation will result in reference leak here. > > > > > > Fix it by replacing it with pm_runtime_resume_and_get to keep usage > > > > > > counter balanced. > > > Yes the rumtime_pm is disabled on failure here and the count would have > > > no consequence... > > > > You should still balance the PM usage counter as it isn't reset for > > example when reloading the driver. > > Should I driver trust that on load PM usage counter is balanced and not > to be reset..? Not sure what you're asking here. But a driver should never leave the PM usage counter unbalanced. > > Using pm_runtime_resume_and_get() is one way of handling this, but > > alternatively you could also move the error_pm label above the > > pm_runtime_put() in the error path. > > That would be a better way I think Johan