Re: [PATCH] blk-sysfs: Rework documention of __blk_release_queue

From: Jens Axboe
Date: Sun Feb 10 2019 - 10:23:32 EST


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@xxxxxxxxx>
>> ---
>> 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