Man page 9 : find_get_page

find_get_page - find and get a page reference

struct page * find_get_page(struct address_space *  mapping , pgoff_t  offset );

mapping
    the address_space to search

offset
    the page index

Is there a pagecache struct page at the given (mapping, offset) tuple? If yes, increment its refcount and return it; if no, return NULL.