Linux Device Drivers V2 Vids
There are a bunch of error numbers defined in linux, the first bunch are in
For fedora 24 /usr/src/kernels/4.11.12-100.fc24.x86_64+debug/include/uapi/asm-generic
Usually one returns -ERROR, while the return from the system is almos always -1
with the actual code error being stored in the thread local variable errno in user space.
https://kukuruku.co/post/writing-a-file-system-in-linux-kernel/