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 5F12D261562; Tue, 11 Feb 2025 17:36:09 +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=1739295372; cv=none; b=MDiLrckPkvyovm+8RvyqAardXuk/2rWUnRt34bm/0By4y7adc4zUPjLqjukG41G51O31wXZg76XicDOr/pUH0w661bDAkFFliKrmva1c4qUm+CTdiinmfVXROY1t/2AWGerzQIO2dTltyBOz9VyBcKjK8zYoQKvS+9aZDKVf1I0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739295372; c=relaxed/simple; bh=pA2c/4v4jIsjXDTHK2U3nVkLaip9cFt3LkM0qkCtz5U=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SAJMW+8JgclemYdLs52XuQTaA1k6pepke9NOPef9EPxqrqJ/PRXgrjDUrWrxKkBkMzIkh0JE3L6nPQatiP4VArHkthaWsWy5bK3vOMRUwJAGGRDvEs975w9F/l/Ld7RBFCf2zB5CUl6p+a6MMIUw7iYagynGWQG5h3Sb88HJubg= 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 4YspVQ5Xkdz6K5p3; Wed, 12 Feb 2025 01:34:54 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id 2A5A61402A4; Wed, 12 Feb 2025 01:36:08 +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 18:36:07 +0100 Date: Tue, 11 Feb 2025 17:36:06 +0000 From: Jonathan Cameron To: Li Ming CC: , , , , , , , Subject: Re: [PATCH v1 7/7] cxl/region: Drop goto pattern of construct_region() Message-ID: <20250211173606.00004d33@huawei.com> In-Reply-To: <20250211075727.351895-8-ming.li@zohomail.com> References: <20250211075727.351895-1-ming.li@zohomail.com> <20250211075727.351895-8-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 15:57:27 +0800 Li Ming wrote: > Some operations need to be procted by the cxl_region_rwsem in construct > region(). Currently, construct_region() uses down_write() and up_write() > for the cxl_region_rwsem, so there is a goto pattern after down_write() > invoked to release cxl_region_rwsem. > > construct region() can be optimized to remove the goto pattern. The > changes are creating a new function called __construct_region() which > will include all checking and operations protected by the > cxl_region_rwsem, and using guard(rwsem_write) to replace down_write() > and up_write() in __construct_region(). > > Signed-off-by: Li Ming > --- > drivers/cxl/core/region.c | 71 +++++++++++++++++++++------------------ > 1 file changed, 39 insertions(+), 32 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 36f3771818d3..170278bdcedc 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -3217,49 +3217,31 @@ static int match_region_by_range(struct device *dev, const void *data) > return rc; > } > > -/* Establish an empty region covering the given HPA range */ > -static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > - struct cxl_endpoint_decoder *cxled) > +static int __construct_region(struct cxl_region *cxlr, This is only factoring out part, so I'm not sure the naming makes sense. I don't have a better name however as this is doing various different things... setup_region() doesn't feel right either... > + struct cxl_root_decoder *cxlrd, > + struct cxl_endpoint_decoder *cxled) > { > struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > - struct cxl_port *port = cxlrd_to_port(cxlrd); > struct range *hpa = &cxled->cxld.hpa_range; > struct cxl_region_params *p; > - struct cxl_region *cxlr; > struct resource *res; > int rc; > > - do { > - cxlr = __create_region(cxlrd, cxled->mode, > - atomic_read(&cxlrd->region_id)); > - } while (IS_ERR(cxlr) && PTR_ERR(cxlr) == -EBUSY); > - > - if (IS_ERR(cxlr)) { > - dev_err(cxlmd->dev.parent, > - "%s:%s: %s failed assign region: %ld\n", > - dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev), > - __func__, PTR_ERR(cxlr)); > - return cxlr; > - } > - > - down_write(&cxl_region_rwsem); > + guard(rwsem_write)(&cxl_region_rwsem); > p = &cxlr->params; > if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE) { > dev_err(cxlmd->dev.parent, > "%s:%s: %s autodiscovery interrupted\n", > dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev), > __func__); > - rc = -EBUSY; > - goto err; > + return -EBUSY; > } > > set_bit(CXL_REGION_F_AUTO, &cxlr->flags); > > res = kmalloc(sizeof(*res), GFP_KERNEL); > - if (!res) { > - rc = -ENOMEM; > - goto err; > - } > + if (!res) > + return -ENOMEM; > > *res = DEFINE_RES_MEM_NAMED(hpa->start, range_len(hpa), > dev_name(&cxlr->dev)); > @@ -3282,7 +3264,7 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > > rc = sysfs_update_group(&cxlr->dev.kobj, get_cxl_region_target_group()); > if (rc) > - goto err; > + return rc; > > dev_dbg(cxlmd->dev.parent, "%s:%s: %s %s res: %pr iw: %d ig: %d\n", > dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev), __func__, > @@ -3291,14 +3273,39 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > > /* ...to match put_device() in cxl_add_to_region() */ > get_device(&cxlr->dev); > - up_write(&cxl_region_rwsem); > > - return cxlr; > + return 0; > +} > > -err: > - up_write(&cxl_region_rwsem); > - devm_release_action(port->uport_dev, unregister_region, cxlr); > - return ERR_PTR(rc); > +/* Establish an empty region covering the given HPA range */ > +static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > + struct cxl_endpoint_decoder *cxled) > +{ > + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > + struct cxl_port *port = cxlrd_to_port(cxlrd); > + struct cxl_region *cxlr; > + int rc; > + > + do { > + cxlr = __create_region(cxlrd, cxled->mode, > + atomic_read(&cxlrd->region_id)); > + } while (IS_ERR(cxlr) && PTR_ERR(cxlr) == -EBUSY); > + > + if (IS_ERR(cxlr)) { > + dev_err(cxlmd->dev.parent, > + "%s:%s: %s failed assign region: %ld\n", > + dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev), > + __func__, PTR_ERR(cxlr)); > + return cxlr; > + } > + > + rc = __construct_region(cxlr, cxlrd, cxled); > + if (rc) { > + devm_release_action(port->uport_dev, unregister_region, cxlr); > + return ERR_PTR(rc); > + } > + > + return cxlr; > } > > int cxl_add_to_region(struct cxl_port *root, struct cxl_endpoint_decoder *cxled)