unsigned pagevec_lookup (struct pagevec * pvec, struct address_space * mapping, pgoff_t start, unsigned nr_pages);
pagevec_lookup will search for and return a group of up to nr_pages pages in the mapping. The pages are placed in pvec. pagevec_lookup takes a reference against the pages in pvec.
The search returns a group of mapping-contiguous pages with ascending indexes. There may be holes in the indices due to not-present pages.
pagevec_lookup returns the number of pages which were found.