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SubjectRe: [PATCH 1/3] chrdev: implement __[un]register_chrdev()
At Thu, 06 Aug 2009 18:13:23 +0900,
Tejun Heo wrote:
>
> [un]register_chrdev() assume minor range 0-255. This patch adds __
> prefixed versions which take @minorbase and @count explicitly.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Greg Kroah-Hartman <gregkh@suse.de>
> ---
> This is updated repost of the make-OSS-device-number-claiming-optional
> patchset.
>
> http://thread.gmane.org/gmane.linux.kernel/873475
>
> Changes from the last take are...
>
> * soundcore now emits standard chrdev module aliases too.
>
> * The sound-slot/service-* module aliases are now scheduled to be
> removed in a year along with the config and kernel parameter to
> disable it.
>
> * sound_insert_unit() updated to deal with minors claimed by others at
> chrdev layer.

I merged this to sound-unstable tree now to check the builds.
I'm going to move it to the sound tree for linux-next in tomorrow or
later.

If anybody still sees the problem with this patch set, please let me
know.


Thanks!

Takashi


>
> Thanks.
>
> fs/char_dev.c | 39 ++++++++++++++++++++++++++-------------
> include/linux/fs.h | 19 ++++++++++++++++---
> 2 files changed, 42 insertions(+), 16 deletions(-)
>
> Index: work/fs/char_dev.c
> ===================================================================
> --- work.orig/fs/char_dev.c
> +++ work/fs/char_dev.c
> @@ -237,8 +237,10 @@ int alloc_chrdev_region(dev_t *dev, unsi
> }
>
> /**
> - * register_chrdev() - Register a major number for character devices.
> + * __register_chrdev() - create and register a cdev occupying a range of minors
> * @major: major device number or 0 for dynamic allocation
> + * @baseminor: first of the requested range of minor numbers
> + * @count: the number of minor numbers required
> * @name: name of this range of devices
> * @fops: file operations associated with this devices
> *
> @@ -254,19 +256,17 @@ int alloc_chrdev_region(dev_t *dev, unsi
> * /dev. It only helps to keep track of the different owners of devices. If
> * your module name has only one type of devices it's ok to use e.g. the name
> * of the module here.
> - *
> - * This function registers a range of 256 minor numbers. The first minor number
> - * is 0.
> */
> -int register_chrdev(unsigned int major, const char *name,
> - const struct file_operations *fops)
> +int __register_chrdev(unsigned int major, unsigned int baseminor,
> + unsigned int count, const char *name,
> + const struct file_operations *fops)
> {
> struct char_device_struct *cd;
> struct cdev *cdev;
> char *s;
> int err = -ENOMEM;
>
> - cd = __register_chrdev_region(major, 0, 256, name);
> + cd = __register_chrdev_region(major, baseminor, count, name);
> if (IS_ERR(cd))
> return PTR_ERR(cd);
>
> @@ -280,7 +280,7 @@ int register_chrdev(unsigned int major,
> for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/'))
> *s = '!';
>
> - err = cdev_add(cdev, MKDEV(cd->major, 0), 256);
> + err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);
> if (err)
> goto out;
>
> @@ -290,7 +290,7 @@ int register_chrdev(unsigned int major,
> out:
> kobject_put(&cdev->kobj);
> out2:
> - kfree(__unregister_chrdev_region(cd->major, 0, 256));
> + kfree(__unregister_chrdev_region(cd->major, baseminor, count));
> return err;
> }
>
> @@ -316,10 +316,23 @@ void unregister_chrdev_region(dev_t from
> }
> }
>
> -void unregister_chrdev(unsigned int major, const char *name)
> +/**
> + * __unregister_chrdev - unregister and destroy a cdev
> + * @major: major device number
> + * @baseminor: first of the range of minor numbers
> + * @count: the number of minor numbers this cdev is occupying
> + * @name: name of this range of devices
> + *
> + * Unregister and destroy the cdev occupying the region described by
> + * @major, @baseminor and @count. This function undoes what
> + * __register_chrdev() did.
> + */
> +void __unregister_chrdev(unsigned int major, unsigned int baseminor,
> + unsigned int count, const char *name)
> {
> struct char_device_struct *cd;
> - cd = __unregister_chrdev_region(major, 0, 256);
> +
> + cd = __unregister_chrdev_region(major, baseminor, count);
> if (cd && cd->cdev)
> cdev_del(cd->cdev);
> kfree(cd);
> @@ -568,6 +581,6 @@ EXPORT_SYMBOL(cdev_alloc);
> EXPORT_SYMBOL(cdev_del);
> EXPORT_SYMBOL(cdev_add);
> EXPORT_SYMBOL(cdev_index);
> -EXPORT_SYMBOL(register_chrdev);
> -EXPORT_SYMBOL(unregister_chrdev);
> +EXPORT_SYMBOL(__register_chrdev);
> +EXPORT_SYMBOL(__unregister_chrdev);
> EXPORT_SYMBOL(directly_mappable_cdev_bdi);
> Index: work/include/linux/fs.h
> ===================================================================
> --- work.orig/include/linux/fs.h
> +++ work/include/linux/fs.h
> @@ -1998,12 +1998,25 @@ extern void bd_release_from_disk(struct
> #define CHRDEV_MAJOR_HASH_SIZE 255
> extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
> extern int register_chrdev_region(dev_t, unsigned, const char *);
> -extern int register_chrdev(unsigned int, const char *,
> - const struct file_operations *);
> -extern void unregister_chrdev(unsigned int, const char *);
> +extern int __register_chrdev(unsigned int major, unsigned int baseminor,
> + unsigned int count, const char *name,
> + const struct file_operations *fops);
> +extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
> + unsigned int count, const char *name);
> extern void unregister_chrdev_region(dev_t, unsigned);
> extern void chrdev_show(struct seq_file *,off_t);
>
> +static inline int register_chrdev(unsigned int major, const char *name,
> + const struct file_operations *fops)
> +{
> + return __register_chrdev(major, 0, 256, name, fops);
> +}
> +
> +static inline void unregister_chrdev(unsigned int major, const char *name)
> +{
> + __unregister_chrdev(major, 0, 256, name);
> +}
> +
> /* fs/block_dev.c */
> #define BDEVNAME_SIZE 32 /* Largest string for a blockdev identifier */
> #define BDEVT_SIZE 10 /* Largest string for MAJ:MIN for blkdev */
>


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