From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2716A2DE715; Wed, 1 Oct 2025 11:59:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759319995; cv=none; b=nPlRS7nfrJUXQa4QPY1iVQ+5r924mo5OjkKWyKeclZKcHfr6xrQWGvHET/EQ/QTeky2ePpqKn7rI/o5u2hFn9NJZ8C1VW6Yhfpk8Nb2EHQnAhQG7l5cYkE0wI7ltNQhbVPGd66gykHIEk4xRdGhCoVekoipKyI6MifAWP3YZ9ls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759319995; c=relaxed/simple; bh=yasRxt5QP0TubpGRVpMM60tA67T2lNp2t5aBrR0AQ7s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cKwrxzj2o9GqqyIVaWgKTSvCEzZ+ktTpY7LJ66ZfdwlN3iUA+Kauln1iWOlyx32yIl5tW9bMtEo2RifZ0XeHo56W3/TTuH3WXnu5YXJTxferJjRp9G902UFtI1kyfEkAGdbybLneuoapaKnHFeYtE6fa2Vg85PGO9HdQQEfM1y8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=WjE0QNHe; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="WjE0QNHe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1759319993; x=1790855993; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=yasRxt5QP0TubpGRVpMM60tA67T2lNp2t5aBrR0AQ7s=; b=WjE0QNHeDgu3DWW/736EDcERF2VYglZm2LSa45y4YwfwWk8RdJpvJDJn 4QU5tqkEFvdkyhOiHhz23kHB/uljsqHkYVXkdUK+lO0UxVzHdJ6shdL/P 92u6tbe7Z0vRoYzVThat+UoIZazyVWsIcviJJHTJ/+fjdqkxqzwsckVU9 N+3x/1GdrxNJU+R5IrlfrfzqXFBUFlRnutIF/lAxNEkOC3GvlBXDkBRs7 sWRgxRzbZQmr2p4GaiBdVsh26X6GKRCtBTDfyjh9Wfr6irU9tKNIRYBFN bmKg82c6J9s6VMhHxG+dR05j8XslEEFRpFKXbhgfHOn9GdjLipLAwHPra Q==; X-CSE-ConnectionGUID: zLIszrsvRBG4C3XJ1+wuJg== X-CSE-MsgGUID: Jk9pcgKrT6WATkL1OAbSGg== X-IronPort-AV: E=McAfee;i="6800,10657,11569"; a="60804574" X-IronPort-AV: E=Sophos;i="6.18,306,1751266800"; d="scan'208";a="60804574" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2025 04:59:53 -0700 X-CSE-ConnectionGUID: nERQSJBORcKpxb9lx/DIGQ== X-CSE-MsgGUID: /UxpTlybTf24alL71cqoqA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,306,1751266800"; d="scan'208";a="178819207" Received: from fpallare-mobl4.ger.corp.intel.com (HELO kekkonen.fi.intel.com) ([10.245.245.14]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2025 04:59:50 -0700 Received: from kekkonen.localdomain (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with SMTP id 0B133121163; Wed, 01 Oct 2025 14:59:47 +0300 (EEST) Date: Wed, 1 Oct 2025 14:59:47 +0300 Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo From: Sakari Ailus To: Ma Ke Cc: bingbu.cao@intel.com, lixu.zhang@intel.com, stanislaw.gruszka@linux.intel.com, mchehab@kernel.org, wentong.wu@intel.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH v5] media: pci: intel: ivsc: improve device reference counting in mei_ace driver Message-ID: References: <20250929013007.1920-1-make24@iscas.ac.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250929013007.1920-1-make24@iscas.ac.cn> Hi Ma, Thanks for the update. On Mon, Sep 29, 2025 at 09:30:07AM +0800, Ma Ke wrote: > The device reference counting in mei_ace_setup_dev_link() was > incomplete, as the reference acquired by device_find_child_by_name() > was not released immediately on the success path. Add put_device() to > properly balance the reference count. Additionally, the redundant > put_device() in mei_ace_remove() is removed. > > Found by code review. The patch seems fine but the commit message is a bit more dramatic than what reality justifies. I'll use this: Put the reference to csi_dev acquired during driver probe in mei_ace_setup_dev_link() inside the same function, instead of during driver unbind in mei_ace_remove(). This can be done as device_link_add() already takes a reference to csi_dev. > > Signed-off-by: Ma Ke > --- > Changes in v5: > - jumped to err instead of err_put to avoid calling put_device() again in err_put as reviewer's instructions; > Changes in v4: > - updated the subject as suggestions; > Changes in v3: > - deleted the tag of Fixes and CC, and moved put_device() to immediately after device_link_add() as suggestions; > Changes in v2: > - modified the put_device() operations and the patch title as suggestions. > --- > drivers/media/pci/intel/ivsc/mei_ace.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/pci/intel/ivsc/mei_ace.c b/drivers/media/pci/intel/ivsc/mei_ace.c > index 98310b8511b1..b306a320b70f 100644 > --- a/drivers/media/pci/intel/ivsc/mei_ace.c > +++ b/drivers/media/pci/intel/ivsc/mei_ace.c > @@ -414,10 +414,11 @@ static int mei_ace_setup_dev_link(struct mei_ace *ace) > /* setup link between mei_ace and mei_csi */ > ace->csi_link = device_link_add(csi_dev, dev, DL_FLAG_PM_RUNTIME | > DL_FLAG_RPM_ACTIVE | DL_FLAG_STATELESS); > + put_device(csi_dev); > if (!ace->csi_link) { > ret = -EINVAL; > dev_err(dev, "failed to link to %s\n", dev_name(csi_dev)); > - goto err_put; > + goto err; > } > > ace->csi_dev = csi_dev; > @@ -522,7 +523,6 @@ static void mei_ace_remove(struct mei_cl_device *cldev) > cancel_work_sync(&ace->work); > > device_link_del(ace->csi_link); > - put_device(ace->csi_dev); > > pm_runtime_disable(&cldev->dev); > pm_runtime_set_suspended(&cldev->dev); -- Regards, Sakari Ailus