Revise proc_ops creation logic in ch2 proc kernel module exercise

[LSKhappychild]

Currently I'm using Linux kernel version 5.15.0 with ubuntu 22.04.1 LTS.
In chapter 2, exercise for creating proc file system kernel module,
provided source code generates following error :

error: passing argument 4 of ‘proc_create’ from incompatible pointer type [-Werror=incompatible-pointer-types] 50 | proc_create(PROC_NAME, 0, NULL, &proc_ops); | ^~~~~~~~~ | | | struct file_operations * In file included from /home/lskhappychild/Desktop/Systems/Linux/ch2/hello.c:16: ./include/linux/proc_fs.h:110:122: note: expected ‘const struct proc_ops *’ but argument is of type ‘struct file_operations *’ 110 | t char *name, umode_t mode, struct proc_dir_entry *parent, const struct proc_ops *proc_ops); | ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~

And this seems to happen due to Linux version compatibility.

So added part needed for compatibility with higher version linux kernel.

[qqwqqw689]

Yes, I encounter the same problem.It need some fix I think

[jpstayfocus]

Here's how to fix it

proc_create(PROC_NAME, 0666, NULL, (const struct proc_ops *) &proc_ops);