chardev: code cleanup for __register_chrdev_region() (4b0be572) · Commits · 戴 / test

fs/char_dev.c

+28 −41

Original line number	Diff line number	Diff line
		@@ -100,10 +100,16 @@ static struct char_device_struct *
		__register_chrdev_region(unsigned int major, unsigned int baseminor,
		int minorct, const char *name)
		{
		struct char_device_struct cd, *cp;
		int ret = 0;
		struct char_device_struct cd, curr, *prev = NULL;
		int ret = -EBUSY;
		int i;

		if (major >= CHRDEV_MAJOR_MAX) {
		pr_err("CHRDEV \"%s\" major requested (%u) is greater than the maximum (%u)\n",
		name, major, CHRDEV_MAJOR_MAX-1);
		return ERR_PTR(-EINVAL);
		}

		if (minorct > MINORMASK + 1 - baseminor) {
		pr_err("CHRDEV \"%s\" minor range requested (%u-%u) is out of range of maximum range (%u-%u) for a single major\n",
		name, baseminor, baseminor + minorct - 1, 0, MINORMASK);
		@@ -126,55 +132,36 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
		major = ret;
		}

		if (major >= CHRDEV_MAJOR_MAX) {
		pr_err("CHRDEV \"%s\" major requested (%u) is greater than the maximum (%u)\n",
		name, major, CHRDEV_MAJOR_MAX-1);
		ret = -EINVAL;
		goto out;
		}

		cd->major = major;
		cd->baseminor = baseminor;
		cd->minorct = minorct;
		strlcpy(cd->name, name, sizeof(cd->name));

		i = major_to_index(major);
		for (curr = chrdevs[i]; curr; prev = curr, curr = curr->next) {
		if (curr->major < major)
		continue;

		for (cp = &chrdevs[i]; cp; cp = &(cp)->next)
		if ((*cp)->major > major \|\|
		((*cp)->major == major &&
		(((*cp)->baseminor >= baseminor) \|\|
		((cp)->baseminor + (cp)->minorct > baseminor))))
		if (curr->major > major)
		break;

		/* Check for overlapping minor ranges. */
		if (cp && (cp)->major == major) {
		int old_min = (*cp)->baseminor;
		int old_max = (cp)->baseminor + (cp)->minorct - 1;
		int new_min = baseminor;
		int new_max = baseminor + minorct - 1;
		if (curr->baseminor + curr->minorct <= baseminor)
		continue;

		/* New driver overlaps from the left. */
		if (new_max >= old_min && new_max <= old_max) {
		ret = -EBUSY;
		goto out;
		}
		if (curr->baseminor >= baseminor + minorct)
		break;

		/* New driver overlaps from the right. */
		if (new_min <= old_max && new_min >= old_min) {
		ret = -EBUSY;
		goto out;
		}

		if (new_min < old_min && new_max > old_max) {
		ret = -EBUSY;
		goto out;
		}
		cd->major = major;
		cd->baseminor = baseminor;
		cd->minorct = minorct;
		strlcpy(cd->name, name, sizeof(cd->name));

		if (!prev) {
		cd->next = curr;
		chrdevs[i] = cd;
		} else {
		cd->next = prev->next;
		prev->next = cd;
		}

		cd->next = *cp;
		*cp = cd;
		mutex_unlock(&chrdevs_lock);
		return cd;
		out:

Admin message