Re: alloc_chrdev_region/unregister_chrdev_region - Issue

["Sandeep K Sinha" <sandeepksinha@xxxxxxxxx>]

On Mon, Dec 8, 2008 at 7:45 PM, Chetan Nanda <chetannanda@xxxxxxxxx> wrote:
> Hi,
>
> I am using 'alloc_chrdev_region' for registering char device range and then
> 'unregister_chrdev_region' for un-registering it.
> But on each insmod I am getting MAJOR number as one less then that of
> previous time.

 /* temporary */
 96         if (major == 0) {
 97                 for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) {
 98                         if (chrdevs[i] == NULL)
 99                                 break;
100                 }
101
102                 if (i == 0) {
103                         ret = -EBUSY;
104                         goto out;
105                 }
106                 major = i;
107                 ret = major;
108         }
109

REF: http://lxr.oss.org.cn/source/fs/char_dev.c#L80
>
> On seeing the code (unregister_chrdev_region) it seems that it just kfree
> the chrdevs[] entry but not set it to NULL which cause for new
> entry in chrdevs[].
>

Thats right, it is like that.
Dont have much idea regarding the same. I think we should assign a
NULL to it for sure.
> Thanks,
> Chetan Nanda
>



-- 
Regards,
Sandeep.





 	
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