From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 17FAA20E6F9; Wed, 19 Feb 2025 17:24:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739985893; cv=none; b=s4ixSisqy8cO3aeZDQgOQ21zZSjG8IzNYRmXxgfF/LVb4/myAapsZaF6Tozxjj+yen6LQ/usf57Mz6SrusInR9Jj7rDEgOPyC5dMHSzn36QIMobdRIjZ7My5zxqEcMX3HzRW5swoTjokkoadX3Dch/fPntLmxxMKtzcuqH+McbU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739985893; c=relaxed/simple; bh=4zbsz1fjaHsLbK4aRx1S+C3TaO1gYP/gaDkgLiYhaTU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d4wuqCUeSY/J5+20YrWY4Ovi/GetZlTOKxTbV/gt8tsG/i04AzYAFtAetxyCtcSPftJSJ4kP6Bie9WDAmQwKwoymOUIXAOu430Ve1kRQEiIWCcebWbb90LsvHLXA1oh+j6iNTES9SrNGObDPX8Ky8Zbd4kKRiUYL0JzhL9OnorU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=G1SEali3; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="G1SEali3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1739985891; x=1771521891; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=4zbsz1fjaHsLbK4aRx1S+C3TaO1gYP/gaDkgLiYhaTU=; b=G1SEali3rdTmQDWcTcGgMqqS+HyAOqa0igAXNZxKC0ZjbOWNc4cPW/SK BWCj0WUa/We8zCT33LxUMoyDMXArbX1FC8lXOMPvtWsTwtt7K0CmWZFjt z4wDsO4EO4bWjHkSWSW8K+Y7sWPgwGPHqEvZohqIZ1vcPVXDRQoirlq9o uBBPXnmql+zjtHWTdKl2sbc32DCxBD96OncxcICsgMgirE99zNkZhSY0Z gORcOKeqmV23s67fetyrsqQx5sxQMiCl46FHC0G+yLlGyi/SIOVUCsCkj DGAxQSpjUzHUwqldgEw34aphT1mZ01Sa7ziyIQURZsAN5PxD4nNjkVWCG g==; X-CSE-ConnectionGUID: 3vQvTSZjQsKKhBGubjos2A== X-CSE-MsgGUID: ThT3w46lReKqRYNf0oyKZA== X-IronPort-AV: E=McAfee;i="6700,10204,11350"; a="44382707" X-IronPort-AV: E=Sophos;i="6.13,299,1732608000"; d="scan'208";a="44382707" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2025 09:24:50 -0800 X-CSE-ConnectionGUID: wrExgqd1R8yjf7dpiYwP2Q== X-CSE-MsgGUID: m4sAUlNOTVe6V952FSwHBw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="115257008" Received: from inaky-mobl1.amr.corp.intel.com (HELO [10.125.110.11]) ([10.125.110.11]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Feb 2025 09:24:42 -0800 Message-ID: <4e30257f-5535-4333-abf5-d424436ee853@intel.com> Date: Wed, 19 Feb 2025 10:24:33 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 7/7] cxl/region: Drop goto pattern of construct_region() To: Li Ming , dave@stgolabs.net, jonathan.cameron@huawei.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250217144828.30651-1-ming.li@zohomail.com> <20250217144828.30651-8-ming.li@zohomail.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <20250217144828.30651-8-ming.li@zohomail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/17/25 7:48 AM, Li Ming wrote: > Some operations need to be protected by the cxl_region_rwsem in > construct_region(). Currently, construct_region() uses down_write() and > up_write() for the cxl_region_rwsem locking, 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_auto_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_auto_region(). > > Signed-off-by: Li Ming Reviewed-by: Dave Jiang > --- > v2: > - Rename __construct_region() to construct_auto_region(). (Jonathan and Dave) > --- > 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 320a3f218131..7a9e51aba9f4 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -3216,49 +3216,31 @@ static int match_region_by_range(struct device *dev, const void *data) > return 0; > } > > -/* 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_auto_region(struct cxl_region *cxlr, > + 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)); > @@ -3281,7 +3263,7 @@ 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__, > @@ -3290,14 +3272,39 @@ 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_auto_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)