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    Subject[PATCH 18/23] Hibernation: Remove swap_map_pages
    Date
    Stop storing swap_map pages in the image. This removes the need
    for a wait_on_bio_chain every MAP_PAGE_ENTRIES pages and thus
    allows the whole image to be written using async I/O.

    Signed-off-by: Nigel Cunningham <nigel@tuxonice.net>
    ---
    kernel/power/block_io.c | 61 +++-------------------------------------------
    1 files changed, 4 insertions(+), 57 deletions(-)
    diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
    index 24b6db5..b068b5a 100644
    --- a/kernel/power/block_io.c
    +++ b/kernel/power/block_io.c
    @@ -156,7 +156,6 @@ struct swap_map_page {

    struct swap_map_handle {
    struct swap_map_page *cur;
    - sector_t cur_swap;
    unsigned int k;
    };

    @@ -168,8 +167,7 @@ extern struct hib_extent_state sector_extents;
    /* Calculate the overhead needed for storing n pages */
    unsigned int hib_bio_overhead(unsigned int nr_pages)
    {
    - return DIV_ROUND_UP(nr_pages, MAP_PAGE_ENTRIES) +
    - DIV_ROUND_UP(hib_extents_storage_needed(&sector_extents),
    + return DIV_ROUND_UP(hib_extents_storage_needed(&sector_extents),
    PAGE_SIZE);
    }

    @@ -235,12 +233,8 @@ int hib_bio_prepare_write(void)
    result = hib_extents_store(&sector_extents);
    result2 = hib_flush_write_buffer();

    - handle.cur_swap = hib_extent_next(&sector_extents);
    handle.k = 0;

    - if (!handle.cur_swap)
    - result = -ENOSPC;
    -
    if (result || result2)
    release_swap_writer();

    @@ -249,41 +243,17 @@ int hib_bio_prepare_write(void)

    int swap_write_page(void *buf, int sync)
    {
    - int error = 0;
    sector_t offset;

    if (!handle.cur)
    return -EINVAL;
    offset = hib_extent_next(&sector_extents);
    - error = write_page(buf, offset, sync);
    - if (error)
    - return error;
    - handle.cur->entries[handle.k++] = offset;
    - if (handle.k >= MAP_PAGE_ENTRIES) {
    - error = hib_wait_on_bio_chain();
    - if (error)
    - goto out;
    - offset = hib_extent_next(&sector_extents);
    - if (!offset)
    - return -ENOSPC;
    - handle.cur->next_swap = offset;
    - error = write_page(handle.cur, handle.cur_swap, 1);
    - if (error)
    - goto out;
    - memset(handle.cur, 0, PAGE_SIZE);
    - handle.cur_swap = offset;
    - handle.k = 0;
    - }
    - out:
    - return error;
    + return write_page(buf, offset, sync);
    }

    int flush_swap_writer(void)
    {
    - if (handle.cur && handle.cur_swap)
    - return write_page(handle.cur, handle.cur_swap, 1);
    - else
    - return -EINVAL;
    + return hib_wait_on_bio_chain();
    }

    /**
    @@ -301,7 +271,6 @@ void release_swap_reader(void)
    int get_swap_reader(unsigned int *flags_p, sector_t first_page)
    {
    int error;
    - sector_t offset;

    handle.cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
    if (!handle.cur)
    @@ -330,41 +299,19 @@ int get_swap_reader(unsigned int *flags_p, sector_t first_page)
    return error;
    }

    - offset = hib_extent_next(&sector_extents);
    -
    - /* Now read the first swap_map_page */
    - error = hib_bio_read_page(offset, handle.cur, 1);
    - if (error) {
    - release_swap_reader();
    - return error;
    - }
    -
    return error;
    }

    int swap_read_page(void *buf, int sync)
    {
    sector_t offset;
    - int error;

    if (!handle.cur)
    return -EINVAL;
    offset = hib_extent_next(&sector_extents);
    if (!offset)
    return -EFAULT;
    - error = hib_bio_read_page(offset, buf, sync);
    - if (error)
    - return error;
    - if (++handle.k >= MAP_PAGE_ENTRIES) {
    - error = hib_wait_on_bio_chain();
    - handle.k = 0;
    - offset = hib_extent_next(&sector_extents);
    - if (!offset)
    - release_swap_reader();
    - else if (!error)
    - error = hib_bio_read_page(offset, handle.cur, 1);
    - }
    - return error;
    + return hib_bio_read_page(offset, buf, sync);
    }

    /* Part Page I/O functions */
    --
    1.7.0.4


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