136  * memset *ra to zero.
139 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)  in file_ra_state_init()  argument
141 	ra->ra_pages = inode_to_bdi(mapping->host)->ra_pages;  in file_ra_state_init()
142 	ra->prev_pos = -1;  in file_ra_state_init()
162 		 * Clean up the remaining folios.  The sizes in ->ra  in read_pages()
170 			rac->ra->size -= nr;  in read_pages()
171 			if (rac->ra->async_size >= nr) {  in read_pages()
172 				rac->ra->async_size -= nr;  in read_pages()
310 	struct file_ra_state *ra = ractl->ra;  in force_page_cache_ra()  local
322 	max_pages = max_t(unsigned long, bdi->io_pages, ra->ra_pages);  in force_page_cache_ra()
340  * for 128k (32 page) max ra
361 static unsigned long get_next_ra_size(struct file_ra_state *ra,  in get_next_ra_size()  argument
364 	unsigned long cur = ra->size;  in get_next_ra_size()
434 				 struct file_ra_state *ra,  in try_context_readahead()  argument
457 	ra->start = index;  in try_context_readahead()
458 	ra->size = min(size + req_size, max);  in try_context_readahead()
459 	ra->async_size = 1;  in try_context_readahead()
487 		struct file_ra_state *ra, unsigned int new_order)  in page_cache_ra_order()  argument
492 	pgoff_t mark = index + ra->size - ra->async_size;  in page_cache_ra_order()
496 	if (!mapping_large_folio_support(mapping) || ra->size < 4)  in page_cache_ra_order()
499 	limit = min(limit, index + ra->size - 1);  in page_cache_ra_order()
505 		while ((1 << new_order) > ra->size)  in page_cache_ra_order()
531 		ra->size += index - limit - 1;  in page_cache_ra_order()
532 		ra->async_size += index - limit - 1;  in page_cache_ra_order()
546 	do_page_cache_ra(ractl, ra->size, ra->async_size);  in page_cache_ra_order()
556 	struct file_ra_state *ra = ractl->ra;  in ondemand_readahead()  local
557 	unsigned long max_pages = ra->ra_pages;  in ondemand_readahead()
580 	expected = round_down(ra->start + ra->size - ra->async_size,  in ondemand_readahead()
582 	if (index == expected || index == (ra->start + ra->size)) {  in ondemand_readahead()
583 		ra->start += ra->size;  in ondemand_readahead()
584 		ra->size = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
585 		ra->async_size = ra->size;  in ondemand_readahead()
606 		ra->start = start;  in ondemand_readahead()
607 		ra->size = start - index;	/* old async_size */  in ondemand_readahead()
608 		ra->size += req_size;  in ondemand_readahead()
609 		ra->size = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
610 		ra->async_size = ra->size;  in ondemand_readahead()
625 	prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;  in ondemand_readahead()
633 	if (try_context_readahead(ractl->mapping, ra, index, req_size,  in ondemand_readahead()
645 	ra->start = index;  in ondemand_readahead()
646 	ra->size = get_init_ra_size(req_size, max_pages);  in ondemand_readahead()
647 	ra->async_size = ra->size > req_size ? ra->size - req_size : ra->size;  in ondemand_readahead()
656 	if (index == ra->start && ra->size == ra->async_size) {  in ondemand_readahead()
657 		add_pages = get_next_ra_size(ra, max_pages);  in ondemand_readahead()
658 		if (ra->size + add_pages <= max_pages) {  in ondemand_readahead()
659 			ra->async_size = add_pages;  in ondemand_readahead()
660 			ra->size += add_pages;  in ondemand_readahead()
662 			ra->size = max_pages;  in ondemand_readahead()
663 			ra->async_size = max_pages >> 1;  in ondemand_readahead()
667 	ractl->_index = ra->start;  in ondemand_readahead()
668 	page_cache_ra_order(ractl, ra, order);  in ondemand_readahead()
682 	if (!ractl->ra->ra_pages || blk_cgroup_congested()) {  in page_cache_sync_ra()
703 	if (!ractl->ra->ra_pages)  in page_cache_async_ra()
782 	struct file_ra_state *ra = ractl->ra;  in readahead_expand()  local
836 		if (ra) {  in readahead_expand()
837 			ra->size++;  in readahead_expand()
838 			ra->async_size++;  in readahead_expand()