Re: [PATCH 1/2] blk-mq: not embed .mq_kobj and ctx->kobj into queue instance

[jianchao.wang]

On 11/16/18 11:28 AM, Ming Lei wrote:
...
>  
> +struct blk_mq_kobj {
> +     struct kobject kobj;
> +};
> +
>  static void blk_mq_sysfs_release(struct kobject *kobj)
>  {
> +     struct blk_mq_kobj *mq_kobj = container_of(kobj, struct blk_mq_kobj,
> +                                                kobj);
> +     kfree(mq_kobj);
> +}
> +
...
>  
> -void blk_mq_sysfs_init(struct request_queue *q)
> +int blk_mq_sysfs_init(struct request_queue *q)
>  {
>       struct blk_mq_ctx *ctx;
>       int cpu;
> +     struct blk_mq_kobj *mq_kobj;
> +
> +     mq_kobj = kzalloc(sizeof(struct blk_mq_kobj), GFP_KERNEL);
> +     if (!mq_kobj)
> +             return -ENOMEM;
>  
> -     kobject_init(&q->mq_kobj, &blk_mq_ktype);
> +     kobject_init(&mq_kobj->kobj, &blk_mq_ktype);
>  
>       for_each_possible_cpu(cpu) {
> -             ctx = per_cpu_ptr(q->queue_ctx, cpu);
> +             ctx = kzalloc_node(sizeof(*ctx), GFP_KERNEL, cpu_to_node(cpu));
> +             if (!ctx)
> +                     goto fail;
> +             *per_cpu_ptr(q->queue_ctx, cpu) = ctx;
>               kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
>       }
> +     q->mq_kobj = &mq_kobj->kobj;
> +     return 0;
> +
> + fail:
> +     for_each_possible_cpu(cpu) {
> +             ctx = *per_cpu_ptr(q->queue_ctx, cpu);
> +             if (ctx)
> +                     kobject_put(&ctx->kobj);
> +     }
> +     kobject_put(&mq_kobj->kobj);
> +     return -ENOMEM;
>  }


blk_mq_kobj looks meaningless, why do we need it, or do I miss something ?
And maybe we should allocate ctx in blk_mq_init_allocated_queue.

Thanks
Jianchao