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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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