19.03.2021 21:18, Minchan Kim пишет:

quoted

quoted

+	if (ZERO_OR_NULL_PTR(cma_kobjs))
+		goto out;
+
+	do {
+		cma = &cma_areas[i];
+		cma->kobj = &cma_kobjs[i];

Does cma really need are pointer to cma_kobj?

Do you mean something like this?

struct cma {
	..
	..
	struct kobject *kobj;
};

Then, how could we we make kobject dynamic model?

We need to get struct cma from kboj like below.

static ssize_t alloc_pages_success_show(struct kobject *kobj,
                                        struct kobj_attribute *attr, char *buf)
{
        struct cma_kobject *cma_kobj = container_of(kobj,
                                                    struct cma_kobject, kobj);
        struct cma *cma = cma_kobj->cma;

        return sysfs_emit(buf, "%llu\n",
                          atomic64_read(&cma->nr_pages_succeeded));
}

So kobj should be not a pointer in the container struct.
Am I missing your point? Otherwise, it would be great if you suggest
better idea.

I meant that cma_kobj->cma is okay, but cma->kobj wasn't really used
anywhere since struct cma can't be released. I.e. we could write
kobject_put(&cma->kobj->kobj) as kobject_put(&cma_kobjs[i].kobj);

But since we won't use the array anymore and maybe will get back to use
the cma_stat, then it will be fine to add the pointer.