/* page_cache_sync_readahead() should be called when a cache miss happened: it will submit the read. The readahead logic may decide to piggyback more pages onto the read request if access patterns suggest it will improve performance.  */
void page_cache_sync_readahead(struct address_space *mapping, struct file_ra_state *ra, struct file *filp, pgoff_t offset, unsigned long req_size)
/* page_cache_sync_readahead() should be called when a cache miss happened: it will submit the read. The readahead logic may decide to piggyback more pages onto the read request if access patterns suggest it will improve performance.  */
void page_cache_sync_readahead(struct address_space *mapping, struct file_ra_state *ra, struct file *filp, pgoff_t offset, unsigned long req_size)
{
	if (!ra->ra_pages)
		return;
	ondemand_readahead(mapping, ra, filp, false, offset, req_size);
}