From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 1D07326BD8E; Tue, 11 Feb 2025 17:26:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739294799; cv=none; b=rOcDHhsAO5MWEboFvDQmgloqywdnG25aZe6T7WaAlobcGNnibLZijio2zGFQtayNLhB7E9t8Tj2DKdix29aMbFjgRhswZQoTG0jjTvCZSdnXn8gWtyVr+/9i3xz9TKXC8kEbqwSIA0BwFAjaQDmX99SUFFcjZp3UaeJvrH76NsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739294799; c=relaxed/simple; bh=5cU+Vpo1UfVf6yBmz7gKTmJhl1QfDDKO2mILu40rFZM=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mOd4E/Sul0V3zlS4nSHYOQTLEtTc7xXEHqXN70DBgNsPCgtVLXwrusE7Amw2hAtEgk8G6uecRgcudMGuUKP1Cmsm+q8x8KUiEBBkZjTyfwyLKklGDAIrY/OuSw6O61LJkjJ/bOcExjUYf0w17xpW1Mueafanl8g02E6JO0XnBRY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4YspG14DzLz6H8Yg; Wed, 12 Feb 2025 01:24:09 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id A8C011402A4; Wed, 12 Feb 2025 01:26:33 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 11 Feb 2025 18:26:33 +0100 Date: Tue, 11 Feb 2025 17:26:31 +0000 From: Jonathan Cameron To: Li Ming CC: , , , , , , , Subject: Re: [PATCH v1 1/7] cxl/core: Use guard() to replace open-coded down_read/write() Message-ID: <20250211172631.00001a34@huawei.com> In-Reply-To: <20250211075727.351895-2-ming.li@zohomail.com> References: <20250211075727.351895-1-ming.li@zohomail.com> <20250211075727.351895-2-ming.li@zohomail.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) 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-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500009.china.huawei.com (7.191.174.84) To frapeml500008.china.huawei.com (7.182.85.71) On Tue, 11 Feb 2025 15:57:21 +0800 Li Ming wrote: > Some down/up_read() and down/up_write() cases can be replaced by a > guard() simply to drop explicit unlock invoked. It helps to align coding > style with current CXL subsystem's. > > Signed-off-by: Li Ming Reviewed-by: Jonathan Cameron I wondered if it was worth doing some early returns and dropping local variables, but on balance think it isn't worth doing. > @@ -364,10 +362,9 @@ resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled) > { > resource_size_t size = 0; > > - down_read(&cxl_dpa_rwsem); > + guard(rwsem_read)(&cxl_dpa_rwsem); > if (cxled->dpa_res) > size = resource_size(cxled->dpa_res); Could return resource_size() here and return 0 below. I'm not sure it gains us much though. > - up_read(&cxl_dpa_rwsem); > > return size; > } > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index e8d11a988fd9..e3bb33109ced 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -3216,10 +3216,9 @@ static int match_region_by_range(struct device *dev, const void *data) > cxlr = to_cxl_region(dev); > p = &cxlr->params; > > - down_read(&cxl_region_rwsem); > + guard(rwsem_read)(&cxl_region_rwsem); > if (p->res && p->res->start == r->start && p->res->end == r->end) > rc = 1; could do return 1 here and return 0 but it doesn't gain us much. > - up_read(&cxl_region_rwsem); > > return rc; > }