137  * memset *ra to zero.
140 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)  in file_ra_state_init()  argument
142 	ra->ra_pages = inode_to_bdi(mapping->host)->ra_pages;  in file_ra_state_init()
143 	ra->prev_pos = -1;  in file_ra_state_init()
163 		 * Clean up the remaining folios.  The sizes in ->ra  in read_pages()
171 			rac->ra->size -= nr;  in read_pages()
172 			if (rac->ra->async_size >= nr) {  in read_pages()
173 				rac->ra->async_size -= nr;  in read_pages()
311 	struct file_ra_state *ra = ractl->ra;  in force_page_cache_ra()  local
323 	max_pages = max_t(unsigned long, bdi->io_pages, ra->ra_pages);  in force_page_cache_ra()
341  * for 128k (32 page) max ra
362 static unsigned long get_next_ra_size(struct file_ra_state *ra,  in get_next_ra_size()  argument
365 	unsigned long cur = ra->size;  in get_next_ra_size()
435 				 struct file_ra_state *ra,  in try_context_readahead()  argument
458 	ra->start = index;  in try_context_readahead()
459 	ra->size = min(size + req_size, max);  in try_context_readahead()
460 	ra->async_size = 1;  in try_context_readahead()
501 		struct file_ra_state *ra, unsigned int new_order)  in page_cache_ra_order()  argument
506 	pgoff_t mark = index + ra->size - ra->async_size;  in page_cache_ra_order()
510 	if (!mapping_large_folio_support(mapping) || ra->size < 4)  in page_cache_ra_order()
513 	limit = min(limit, index + ra->size - 1);  in page_cache_ra_order()
519 		while ((1 << new_order) > ra->size)  in page_cache_ra_order()
545 		ra->size += index - limit - 1;  in page_cache_ra_order()
546 		ra->async_size += index - limit - 1;  in page_cache_ra_order()
560 	do_page_cache_ra(ractl, ra->size, ra->async_size);  in page_cache_ra_order()
570 	struct file_ra_state *ra = ractl->ra;  in ondemand_readahead()  local
571 	unsigned long max_pages = ra->ra_pages;  in ondemand_readahead()
594 	expected = round_up(ra->start + ra->size - ra->async_size,  in ondemand_readahead()
596 	if (index == expected || index == (ra->start + ra->size)) {  in ondemand_readahead()
597 		ra->start += ra->size;  in ondemand_readahead()
598 		ra->size = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
599 		ra->async_size = ra->size;  in ondemand_readahead()
620 		ra->start = start;  in ondemand_readahead()
621 		ra->size = start - index;	/* old async_size */  in ondemand_readahead()
622 		ra->size += req_size;  in ondemand_readahead()
623 		ra->size = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
624 		ra->async_size = ra->size;  in ondemand_readahead()
639 	prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;  in ondemand_readahead()
647 	if (try_context_readahead(ractl->mapping, ra, index, req_size,  in ondemand_readahead()
659 	ra->start = index;  in ondemand_readahead()
660 	ra->size = get_init_ra_size(req_size, max_pages);  in ondemand_readahead()
661 	ra->async_size = ra->size > req_size ? ra->size - req_size : ra->size;  in ondemand_readahead()
670 	if (index == ra->start && ra->size == ra->async_size) {  in ondemand_readahead()
671 		add_pages = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
672 		if (ra->size + add_pages <= max_pages) {  in ondemand_readahead()
673 			ra->async_size = add_pages;  in ondemand_readahead()
674 			ra->size += add_pages;  in ondemand_readahead()
676 			ra->size = max_pages;  in ondemand_readahead()
677 			ra->async_size = max_pages >> 1;  in ondemand_readahead()
681 	ractl->_index = ra->start;  in ondemand_readahead()
682 	page_cache_ra_order(ractl, ra, order);  in ondemand_readahead()
696 	if (!ractl->ra->ra_pages || blk_cgroup_congested()) {  in page_cache_sync_ra()
717 	if (!ractl->ra->ra_pages)  in page_cache_async_ra()
795 	struct file_ra_state *ra = ractl->ra;  in readahead_expand()  local
844 		if (ra) {  in readahead_expand()
845 			ra->size++;  in readahead_expand()
846 			ra->async_size++;  in readahead_expand()