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SubjectRe: [PATCH 4/5] uio: Support 2^MINOR_BITS minors
On Tue, 14 Sep 2010, Eric W. Biederman wrote:

>
> register_chrdev limits uio devices to 256 minor numbers which causes
> problems on one system I have with 384+ uio devices. So instead set
> UIO_MAX_DEVICES to the maximum number of minors and use
> alloc_chrdev_region to reserve the uio minors.
>
> The final result is that the code works the same but the uio driver now
> supports any minor the idr allocator comes up with.
>
> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>

One minor nit:

> + result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
> + if (result)
> + goto out;

return result;

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

> +
> + result = -ENOMEM;
> + cdev = cdev_alloc();
> + if (!cdev)
> + goto out_unregister;
> +
> + cdev->owner = THIS_MODULE;
> + cdev->ops = &uio_fops;
> + kobject_set_name(&cdev->kobj, "%s", name);
> +
> + result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
> + if (result)
> + goto out_put;
> +
> + uio_major = MAJOR(uio_dev);
> + uio_cdev = cdev;
> + result = 0;
> +out:
> + return result;
> +out_put:
> + kobject_put(&cdev->kobj);
> +out_unregister:
> + unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
> + goto out;
> }
>
> static void uio_major_cleanup(void)
> {
> - unregister_chrdev(uio_major, "uio");
> + unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
> + cdev_del(uio_cdev);
> }
>
> static int init_uio_class(void)
> --
> 1.7.2.2
>
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