Re: [PATCH v7 1/3] llist: Add a lock-less list variant terminated by a sentinel node

From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Jens Axboe" <axboe@kernel.dk>,
	cgroups@vger.kernel.org, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, "Ming Lei" <ming.lei@redhat.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michal Koutný" <mkoutny@suse.com>
Subject: Re: [PATCH v7 1/3] llist: Add a lock-less list variant terminated by a sentinel node
Date: Mon, 3 Oct 2022 13:40:05 -0400	[thread overview]
Message-ID: <87e7cd70-4ab6-f33b-ce26-afe2c7c04faa@redhat.com> (raw)
In-Reply-To: <YzsdsjlMMDFwLOzR@slm.duckdns.org>

On 10/3/22 13:36, Tejun Heo wrote:
> Hello,
>
> On Mon, Oct 03, 2022 at 01:32:49PM -0400, Waiman Long wrote:
>> What my current thinking is to make llist works with both NULL and sentinel
>> terminated lockless list. Users who wish to use the sentinel terminated
>> version will have to use special sentinel version of LLIST_HEAD() macro and
>> llist_del_all() and __llist_del_all() functions. In this way, I don't need
>> to touch an existing users of llist while minimizing code redundancy. What
>> do you think?
> Wouldn't that be more error-prone in the long term? I'd just bite the bullet
> and convert the empty tests. It is a hassle to find them but given that it's
> just the head node testing, it hopefully wouldn't be too bad.

OK, I will take a further look at what changes will be needed by the 
existing llist users.

Thanks,
Longman