/**
* walk_page_range - walk page table with caller specific callbacks
+ * @start: start address of the virtual address range
+ * @end: end address of the virtual address range
+ * @walk: mm_walk structure defining the callbacks and the target address space
*
* Recursively walk the page table tree of the process represented by @walk->mm
* within the virtual address range [@start, @end). During walking, we can do