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/*
* 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 | REQ_UNPLUG;
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;
}
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