Yes, I'd seen that but the question is that whether can it be NULL? I had gone through the function chains from where it is called but couldn't find where can it be NULL? Regards, Vishal. -----Original Message----- From: kernelnewbies-bounce@xxxxxxxxxxxx [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of tyler@xxxxxxxx Sent: Wednesday, April 26, 2006 4:20 PM To: kernelnewbies@xxxxxxxxxxxx Subject: Re: function "class_device_add" in inux26/drivers/base/class.c On Wed, Apr 26, 2006 at 11:23:39AM +0530, Vishal Sharda wrote: > > In the function "class_device_add" in inux26/drivers/base/class.c > There is one statement: > > parent = class_get(class_dev->class); > > My question is that can return value of class_get i.e. value of parent > be NULL? > > I tried to track it down and couldn't find the instance where it can be > NULL. Hi, >From linux-2.6.16, the class_get function is : struct class * class_get(struct class * cls) { if (cls) return container_of(subsys_get(&cls->subsys), struct class, subsys); return NULL; } So class_get(class_dev->class) returns NULL if class_dev->class is NULL. If a class_dev struct has been allocated but not been init, the pointer will be NULL. It's just a sanity check. -- tyler tyler@xxxxxxxx ___________________________________________________________________________ Faites de Yahoo! votre page d'accueil sur le web pour retrouver directement vos services préférés : vérifiez vos nouveaux mails, lancez vos recherches et suivez l'actualité en temps réel. Rendez-vous sur http://fr.yahoo.com/set -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/ **************** CAUTION - Disclaimer ***************** This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. ***INFOSYS******** End of Disclaimer ********INFOSYS*** -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
