Linux Device Drivers

vremap

The vremap function, described in Section 7.3 in Chapter 7, got a new name with the advent of version 2.1. Only the name has changed, and the function called ioremap takes the same arguments as the old vremap. The corresponding free function is iounmap, which replaces vfree to release remapped addresses.

The change is meant to underline the real role of the function: remapping I/O space to a virtual address in kernel space. The header sysdep-2.1.h enforces the new convention, and it #defines ioremap and iounmap to the 2.0 equivalents when compiled against version 2.0.