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

[Ming Lei <ming.lei@redhat.com>]

On Fri, Nov 16, 2018 at 02:11:07PM +0800, jianchao.wang wrote:
> 
> 
> 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 ?

Right, it should have been allocated directly.

> And maybe we should allocate ctx in blk_mq_init_allocated_queue.

Looks either way is fine.


Thanks,
Ming