Root/kernel/power/block_io.c

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_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

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