mm/readahead: pass readahead_control to force_page_cache_ra

			     unsigned long addr, unsigned long end,

			     struct zap_details *details);

void force_page_cache_readahead(struct address_space *, struct file *,

		pgoff_t index, unsigned long nr_to_read);

void do_page_cache_ra(struct readahead_control *,

		unsigned long nr_to_read, unsigned long lookahead_size);

void do_page_cache_ra(struct readahead_control *, unsigned long nr_to_read,

		unsigned long lookahead_size);

void force_page_cache_ra(struct readahead_control *, unsigned long nr);

static inline void force_page_cache_readahead(struct address_space *mapping,

		struct file *file, pgoff_t index, unsigned long nr_to_read)

{

	DEFINE_READAHEAD(ractl, file, mapping, index);

	force_page_cache_ra(&ractl, nr_to_read);

}

/*

 * Submit IO for the read-ahead request in file_ra_state.

 * Chunk the readahead into 2 megabyte units, so that we don't pin too much

 * memory at once.

 */

void force_page_cache_readahead(struct address_space *mapping,

		struct file *file, pgoff_t index, unsigned long nr_to_read)

void force_page_cache_ra(struct readahead_control *ractl,

		unsigned long nr_to_read)

{

	DEFINE_READAHEAD(ractl, file, mapping, index);

	struct address_space *mapping = ractl->mapping;

	struct backing_dev_info *bdi = inode_to_bdi(mapping->host);

	struct file_ra_state *ra = &file->f_ra;

	unsigned long max_pages;

	struct file_ra_state *ra = &ractl->file->f_ra;

	unsigned long max_pages, index;

	if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages &&

			!mapping->a_ops->readahead))

	 * If the request exceeds the readahead window, allow the read to

	 * be up to the optimal hardware IO size

	 */

	index = readahead_index(ractl);

	max_pages = max_t(unsigned long, bdi->io_pages, ra->ra_pages);

	nr_to_read = min(nr_to_read, max_pages);

	nr_to_read = min_t(unsigned long, nr_to_read, max_pages);

	while (nr_to_read) {

		unsigned long this_chunk = (2 * 1024 * 1024) / PAGE_SIZE;

		if (this_chunk > nr_to_read)

			this_chunk = nr_to_read;

		do_page_cache_ra(&ractl, this_chunk, 0);

		ractl->_index = index;

		do_page_cache_ra(ractl, this_chunk, 0);

		index += this_chunk;

		nr_to_read -= this_chunk;

	/* be dumb */

	if (filp && (filp->f_mode & FMODE_RANDOM)) {

		force_page_cache_readahead(mapping, filp, index, req_count);

		force_page_cache_ra(&ractl, req_count);

		return;

	}