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

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