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Subject: Re: [PATCH] blk-sysfs: Rework documention of __blk_release_queue
To:     Marcos Paulo de Souza <marcos.souza.org@gmail.com>,
        linux-kernel@vger.kernel.org
Cc:     "open list:BLOCK LAYER" <linux-block@vger.kernel.org>
References: <20190131011139.2264742-1-marcos.souza.org@gmail.com>
 <02fcaaa4-3667-7144-5ca2-4e5346380439@gmail.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <813bdf91-83de-332d-5d6b-2287039578b5@kernel.dk>
Date:   Sun, 10 Feb 2019 08:23:24 -0700
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On 2/9/19 11:34 AM, Marcos Paulo de Souza wrote:
> Ping :)
> 
> On 1/30/19 11:11 PM, Marcos Paulo de Souza wrote:
>> The Notes section of the comment was removed, because now
>> blk_release_queue can only be executed from blk_cleanup_queue (being
>> called when the q->kobj reaches zero), and also blk_init_queue was removed
>> in a1ce35fa4985.
>>
>> Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
>> ---
>>  This is basically a v2 of https://lkml.org/lkml/2019/1/14/1098
>>
>>  But, I tried to describe when this function is called, removing redundancies.
>>  Maybe it would be better placed in blk-core.c, where the q->kobj is initialized
>>  with blk_queue_ktype (which .release pointer points to blk_release_queue)?
>>
>>  block/blk-sysfs.c | 19 +++++++------------
>>  1 file changed, 7 insertions(+), 12 deletions(-)
>>
>> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
>> index 590d1ef2f961..d4dea9179fa6 100644
>> --- a/block/blk-sysfs.c
>> +++ b/block/blk-sysfs.c
>> @@ -817,21 +817,16 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head)
>>  }
>>  
>>  /**
>> - * __blk_release_queue - release a request queue when it is no longer needed
>> + * __blk_release_queue - release a request queue
>>   * @work: pointer to the release_work member of the request queue to be released
>>   *
>>   * Description:
>> - *     blk_release_queue is the counterpart of blk_init_queue(). It should be
>> - *     called when a request queue is being released; typically when a block
>> - *     device is being de-registered. Its primary task it to free the queue
>> - *     itself.
>> - *
>> - * Notes:
>> - *     The low level driver must have finished any outstanding requests first
>> - *     via blk_cleanup_queue().
>> - *
>> - *     Although blk_release_queue() may be called with preemption disabled,
>> - *     __blk_release_queue() may sleep.
>> + *     This function is called when a block device is being de-registered. The

unregistered

>> + *     process of releasing a request queue starts with blk_cleanup_queue, which
>> + *     set the appropriate flags and the calls blk_put_queue, that decrements

s/the/then

>> + *     the reference counter of the request queue. Once the reference counter
>> + *     of the request queue reaches zero, blk_release_queue is called to release
>> + *     all allocated resources of the request queue.
>>   */
>>  static void __blk_release_queue(struct work_struct *work)
>>  {
>>


-- 
Jens Axboe