1/*
2 * This file provides functions for block I/O operations on swap/file.
3 *
4 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
5 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/bio.h>
11#include <linux/kernel.h>
12#include <linux/pagemap.h>
13#include <linux/swap.h>
14
15#include "power.h"
16
17/**
18 *	submit - submit BIO request.
19 *	@rw:	READ or WRITE.
20 *	@off	physical offset of page.
21 *	@page:	page we're reading or writing.
22 *	@bio_chain: list of pending biod (for async reading)
23 *
24 *	Straight from the textbook - allocate and initialize the bio.
25 *	If we're reading, make sure the page is marked as dirty.
26 *	Then submit it and, if @bio_chain == NULL, wait.
27 */
28static int submit(int rw, struct block_device *bdev, sector_t sector,
29		struct page *page, struct bio **bio_chain)
30{
31	const int bio_rw = rw | REQ_SYNC;
32	struct bio *bio;
33
34	bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
35	bio->bi_iter.bi_sector = sector;
36	bio->bi_bdev = bdev;
37	bio->bi_end_io = end_swap_bio_read;
38
39	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
40		printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
41			(unsigned long long)sector);
42		bio_put(bio);
43		return -EFAULT;
44	}
45
46	lock_page(page);
47	bio_get(bio);
48
49	if (bio_chain == NULL) {
50		submit_bio(bio_rw, bio);
51		wait_on_page_locked(page);
52		if (rw == READ)
53			bio_set_pages_dirty(bio);
54		bio_put(bio);
55	} else {
56		if (rw == READ)
57			get_page(page);	/* These pages are freed later */
58		bio->bi_private = *bio_chain;
59		*bio_chain = bio;
60		submit_bio(bio_rw, bio);
61	}
62	return 0;
63}
64
65int hib_bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
66{
67	return submit(READ, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
68			virt_to_page(addr), bio_chain);
69}
70
71int hib_bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
72{
73	return submit(WRITE, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
74			virt_to_page(addr), bio_chain);
75}
76
77int hib_wait_on_bio_chain(struct bio **bio_chain)
78{
79	struct bio *bio;
80	struct bio *next_bio;
81	int ret = 0;
82
83	if (bio_chain == NULL)
84		return 0;
85
86	bio = *bio_chain;
87	if (bio == NULL)
88		return 0;
89	while (bio) {
90		struct page *page;
91
92		next_bio = bio->bi_private;
93		page = bio->bi_io_vec[0].bv_page;
94		wait_on_page_locked(page);
95		if (!PageUptodate(page) || PageError(page))
96			ret = -EIO;
97		put_page(page);
98		bio_put(bio);
99		bio = next_bio;
100	}
101	*bio_chain = NULL;
102	return ret;
103}
104