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

Ming Lei
2018-11-16T07:52:34Z

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