Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <078e8084-8fea-5b69-89a6-9488a28163cf@kernel.dk>
Date:   Thu, 31 Mar 2022 17:09:51 -0600
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [Drbd-dev] [PATCH 2/2] drbd: remove check of list iterator
 against head past the loop body
Content-Language: en-US
To:     =?UTF-8?Q?Christoph_B=c3=b6hmwalder?= 
        <christoph.boehmwalder@linbit.com>,
        Jakob Koschel <jakobkoschel@gmail.com>
Cc:     linux-kernel@vger.kernel.org, "Bos, H.J." <h.j.bos@vu.nl>,
        Brian Johannesmeyer <bjohannesmeyer@gmail.com>,
        linux-block@vger.kernel.org,
        Cristiano Giuffrida <c.giuffrida@vu.nl>,
        Lars Ellenberg <lars.ellenberg@linbit.com>,
        Mike Rapoport <rppt@kernel.org>, drbd-dev@lists.linbit.com,
        Philipp Reisner <philipp.reisner@linbit.com>
References: <20220331220349.885126-1-jakobkoschel@gmail.com>
 <20220331220349.885126-2-jakobkoschel@gmail.com>
 <4dcedb78-355f-ed1a-9af1-27e9e63b5643@linbit.com>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <4dcedb78-355f-ed1a-9af1-27e9e63b5643@linbit.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 3/31/22 4:28 PM, Christoph B?hmwalder wrote:
> Am 01.04.22 um 00:03 schrieb Jakob Koschel:
>> When list_for_each_entry() completes the iteration over the whole list
>> without breaking the loop, the iterator value will be a bogus pointer
>> computed based on the head element.
>>
>> While it is safe to use the pointer to determine if it was computed
>> based on the head element, either with list_entry_is_head() or
>> &pos->member == head, using the iterator variable after the loop should
>> be avoided.
>>
>> In preparation to limit the scope of a list iterator to the list
>> traversal loop, use a dedicated pointer to point to the found element [1].
>>
> 
> Hi Jakob,
> 
> Both of these look good to me, thanks.
> 
> Reviewed-by: Christoph B?hmwalder <christoph.boehmwalder@linbit.com>

Applied both, but shortened title of this commit. Jakob, please keep it
within the usual 74 chars. In general, it's great to use a cover letter
for anything that's more than one patch. Just some pointers if you're
doing more of these.

-- 
Jens Axboe