block_io.c

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/*
 * This file provides functions for block I/O operations on swap/file.
 *
 * Copyright (C) 1998,2001-2005 Pavel Machek <[email protected]>
 * Copyright (C) 2006 Rafael J. Wysocki <[email protected]>
 *
 * 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"

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;
}