if cdev_add() fails, do you need to "put" the cdev's kobject?

Robert P. J. Day rpjday at crashcourse.ca
Tue May 3 17:46:05 EDT 2011


  still perusing various drivers to use as examples in class, and i
ran across this snippet in the load routine of drivers/char/raw.c:

===== start excerpt =====

        cdev_init(&raw_cdev, &raw_fops);
        ret = cdev_add(&raw_cdev, dev, MAX_RAW_MINORS);
        if (ret) {
                kobject_put(&raw_cdev.kobj);
                goto error_region;
        }

===== end =====

  of course it's wise to check the return code from cdev_add() to make
sure it worked, but is it really necessary to call kobject_put()
there?  i don't recall other character drivers calling that if they
note that cdev_add() failed.  it's probably harmless, but it can't be
necessary, can it?  unless that driver is doing something unusual
somewhere else in its code.

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================



More information about the Kernelnewbies mailing list