Received-SPF: pass (google.com: domain of linux-kernel+bounces-133728-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Message-ID: <6f43f4be-f2da-4bc5-a70c-377599c9ec46@intel.com>
Date: Fri, 5 Apr 2024 17:02:23 -0700
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 05/26] cxl/core: Simplify cxl_dpa_set_mode()
Content-Language: en-US
To: Ira Weiny <ira.weiny@intel.com>, Fan Ni <fan.ni@samsung.com>,
 Jonathan Cameron <Jonathan.Cameron@huawei.com>,
 Navneet Singh <navneet.singh@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
 Davidlohr Bueso <dave@stgolabs.net>,
 Alison Schofield <alison.schofield@intel.com>,
 Vishal Verma <vishal.l.verma@intel.com>, linux-btrfs@vger.kernel.org,
 linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240324-dcd-type2-upstream-v1-0-b7b00d623625@intel.com>
 <20240324-dcd-type2-upstream-v1-5-b7b00d623625@intel.com>
 <922007a0-3f85-4a40-80e4-5c906e6dd2c8@intel.com>
 <66104f505de74_e9f9f294f5@iweiny-mobl.notmuch>
From: Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <66104f505de74_e9f9f294f5@iweiny-mobl.notmuch>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit


On 4/5/24 12:21 PM, Ira Weiny wrote:
> Dave Jiang wrote:
>>
>>
>> On 3/24/24 4:18 PM, Ira Weiny wrote:
>>> cxl_dpa_set_mode() checks the mode for validity two times, once outside
>>> of the DPA RW semaphore and again within.  The function is not in a
>>> critical path.  Prior to Dynamic Capacity the extra check was not much
>>> of an issue.  The addition of DC modes increases the complexity of
>>> the check.
>>>
>>> Simplify the mode check before adding the more complex DC modes.
>>
>> I would augment this by saying simplify "by using scope-based resource menagement".
> 
> However, using the guard cleanup is not really the simplification here.  It is
> more about checking the mode a single time.
> 
> That said I will change this to:
> 
> Simplify the mode check and convert to use of a cleanup guard.

Ok

> 
> Ira