On Wed, Sep 10, 2014 at 2:43 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Tue, Sep 09, 2014 at 09:05:46PM +0800, Ming Lei wrote:
>> This patch introduces 'struct blk_flush_queue' and puts all
>> flush machinery related stuff into this strcuture, so that
>
> s/stuff/fields/
> s/strcuture/structure/
>
> Looks good, but a few more nitpicks below.
>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
>
>> +int blk_init_flush(struct request_queue *q)
>> +{
>> + int ret;
>> + struct blk_flush_queue *fq = kzalloc(sizeof(*fq), GFP_KERNEL);
>>
>> + if (!fq)
>> return -ENOMEM;
>>
>> + q->fq = fq;
>
> I think it would be cleaner to return the flush data structure and
> assign it in the caller.
OK, and most of this part is transitional.
>
>> + INIT_LIST_HEAD(&fq->flush_queue[0]);
>> + INIT_LIST_HEAD(&fq->flush_queue[1]);
>> + INIT_LIST_HEAD(&fq->flush_data_in_flight);
>> +
>> + if (q->mq_ops) {
>> + ret = blk_mq_init_flush(q);
>
> I think we can just remove blk_mq_init_flush now that it's only
> called in blk-flush.c anyway.
blk_mq_init_flush() will become bigger in following patch.
>> void blk_exit_flush(struct request_queue *q)
>> {
>> + if (q->mq_ops)
>> + blk_mq_exit_flush(q);
>> + else {
>> + struct blk_flush_queue *fq = blk_get_flush_queue(q);
>> + kfree(fq->flush_rq);
>> + kfree(fq);
>> + }
>
> Similarly I would pass the flush structure here.
OK.
>
>> +struct blk_flush_queue {
>> + unsigned int flush_queue_delayed:1;
>> + unsigned int flush_pending_idx:1;
>> + unsigned int flush_running_idx:1;
>> + unsigned long flush_pending_since;
>> + struct list_head flush_queue[2];
>> + struct list_head flush_data_in_flight;
>> + struct request *flush_rq;
>> + spinlock_t mq_flush_lock;
>> +};
>
> As this isn't really a queue I would call it blk_flush_data.
It is sort of a queue since there is a double buffer flush queue.
>
>> +static inline struct blk_flush_queue *blk_get_flush_queue(
>> + struct request_queue *q)
>> +{
>> + return q->fq;
>> +}
>
> I don't think there is a need for this helper.
No, the helper can simplify the following patch a lot since
the flush queue data is always obtained from this helper in both
legacy and mq case, which will take per-hw_queue flush queue.
Thanks,
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