微視linux 通用塊層之bio

int mpage_readpages(struct address_space *mapping, struct list_head *pages,
				unsigned nr_pages, get_block_t get_block)
{
	for (page_idx = 0; page_idx < nr_pages; page_idx++){
		struct page *page = list_entry(pages->prev, struct page, lru);
		bio = do_mpage_readpage(bio, page,
					nr_pages - page_idx,
					&last_block_in_bio, &map_bh,
					&first_logical_block,
					get_block);
		=>static struct bio *
		do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
				sector_t *last_block_in_bio, struct buffer_head *map_bh,
				unsigned long *first_logical_block, get_block_t get_block)
		{
			if (bio && (*last_block_in_bio != blocks[0] - 1))
				bio = mpage_bio_submit(READ, bio);
				
		alloc_new:
			if (bio == NULL) {
				bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
						min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
						GFP_KERNEL);
			}
			if (bio_add_page(bio, page, length, 0) < length) {
				bio = mpage_bio_submit(READ, bio);
				goto alloc_new;
			}
		}
	}
	if (bio)
		mpage_bio_submit(READ, bio);
	return 0;	
		
}

bio與bio_vec
https://blog.csdn.net/zhufengtianya/article/details/42145985

宋寶華： 文件讀寫（BIO）波瀾壯闊的一生
https://blog.csdn.net/juS3Ve/article/details/79890688