swsusp: do not use page flags

Make swsusp use memory bitmaps instead of page flags for marking 'nosave' and
free pages.  This allows us to 'recycle' two page flags that can be used for
other purposes.  Also, the memory needed to store the bitmaps is allocated
when necessary (ie.  before the suspend) and freed after the resume which is
more reasonable.

The patch is designed to minimize the amount of changes and there are some
nice simplifications and optimizations possible on top of it.  I am going to
implement them separately in the future.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 7cf6713b2325..845acd84cb23 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -52,6 +52,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
                 return -ENOSYS;
 
+        if(create_basic_memory_bitmaps())
+                return -ENOMEM;
+
         nonseekable_open(inode, filp);
         data = &snapshot_state;
         filp->private_data = data;
@@ -77,6 +80,7 @@ static int snapshot_release(struct inode *inode, struct file *filp)
         struct snapshot_data *data;
 
         swsusp_free();
+        free_basic_memory_bitmaps();
         data = filp->private_data;
         free_all_swap_pages(data->swap, data->bitmap);
         free_bitmap(data->bitmap);