/* * This file provides functions for block I/O operations on swap/file. * * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz> * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> * * This file is released under the GPLv2. */ #include <linux/bio.h>#include <linux/kernel.h>#include <linux/pagemap.h>#include <linux/swap.h> #include "power.h" /** *	submit - submit BIO request. *	@rw:	READ or WRITE. *	@off	physical offset of page. *	@page:	page we're reading or writing. *	@bio_chain: list of pending biod (for async reading) * *	Straight from the textbook - allocate and initialize the bio. *	If we're reading, make sure the page is marked as dirty. *	Then submit it and, if @bio_chain == NULL, wait. */static int submit(int rw, struct block_device *bdev, sector_t sector,		struct page *page, struct bio **bio_chain){	const int bio_rw = rw | REQ_SYNC;	struct bio *bio; 	bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);	bio->bi_sector = sector;	bio->bi_bdev = bdev;	bio->bi_end_io = end_swap_bio_read; 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {		printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",			(unsigned long long)sector);		bio_put(bio);		return -EFAULT;	} 	lock_page(page);	bio_get(bio); 	if (bio_chain == NULL) {		submit_bio(bio_rw, bio);		wait_on_page_locked(page);		if (rw == READ)			bio_set_pages_dirty(bio);		bio_put(bio);	} else {		if (rw == READ)			get_page(page);	/* These pages are freed later */		bio->bi_private = *bio_chain;		*bio_chain = bio;		submit_bio(bio_rw, bio);	}	return 0;} int hib_bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain){	return submit(READ, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),			virt_to_page(addr), bio_chain);} int hib_bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain){	return submit(WRITE, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),			virt_to_page(addr), bio_chain);} int hib_wait_on_bio_chain(struct bio **bio_chain){	struct bio *bio;	struct bio *next_bio;	int ret = 0; 	if (bio_chain == NULL)		return 0; 	bio = *bio_chain;	if (bio == NULL)		return 0;	while (bio) {		struct page *page; 		next_bio = bio->bi_private;		page = bio->bi_io_vec[0].bv_page;		wait_on_page_locked(page);		if (!PageUptodate(page) || PageError(page))			ret = -EIO;		put_page(page);		bio_put(bio);		bio = next_bio;	}	*bio_chain = NULL;	return ret;}