How to find out MINOR device number in modern linux in kernel mode?

Question

linux

Good afternoon,
n-years ago I wrote a driver for a custom device for the then versions of Linux kernels.
Today I had to dust it off and run this driver on fresh Linux (Ubuntu 16).
But an error occurred during compilation:
struct file has no member f_dentry
It swears at the line where I get the minor device number:
minor = MINOR(filp->f_dentry->d_inode->i_rdev);
(filp is a struct file *filp)
Please tell me how to get the minor device number correctly now?
Thanks

Answer 1

filp->f_path.dentry->d_inode->i_rdevinstead offilp->f_dentry->d_inode->i_rdev

Answer 2

C, the /sys and /udev subsystems appeared, most device numbers are assigned dynamically at boot time. I think we need to look in the direction of udev and how it gets device numbers.
I'm not a developer myself, but I hope the links will help or lead to the right thoughts.
https://superuser.com/questions/686774/what-proble...
https://unix.stackexchange.com/questions/104836/ho...
https://unix.stackexchange.com/questions/315186/ ho...