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  */
  28 static 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 | REQ_UNPLUG;
  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
  65 int 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
  71 int 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
  77 int 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 }