Man page 9 : filemap_fault

filemap_fault - read in file data for page fault handling

int filemap_fault(struct vm_area_struct *  vma , struct vm_fault *  vmf );

vma
    vma in which the fault was taken

vmf
    struct vm_fault containing details of the fault

filemap_fault is invoked via the vma operations vector for a mapped memory region to read in file data during a page fault.

The gotoAqs are kind of ugly, but this streamlines the normal case of having it in the page cache, and handles the special cases reasonably without having a lot of duplicated code.