On Tue, Feb 16, 2021 at 05:05:25PM +0100, Maciej Kwapulinski wrote: > +static inline struct gna_private *inode_to_gna(struct inode *inode) > +{ > + return container_of(inode->i_cdev, struct gna_private, cdev); > +} > + > +static int gna_open(struct inode *inode, struct file *f) > +{ > + struct gna_file_private *file_priv; > + struct gna_private *gna_priv; > + > + gna_priv = inode_to_gna(inode); > + if (!gna_priv) > + return -ENODEV; Why are you testing for things that is impossible to ever happen? Please go read your own function for proof... {sigh} greg k-h