[PATCH] mm: add a new function (needed for swap suspend)

This adds the function get_swap_page_of_type() allowing us to specify an index
in swap_info[] and select a swap_info_struct structure to be used for
allocating a swap page.

This function (or another one of similar functionality) will be necessary for
implementing the image-writing part of swsusp in the user space.   It can also
be used for simplifying the current in-kernel implementation of the
image-writing part of swsusp.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Rafael J. Wysocki 2006-01-06 00:16:37 -08:00 committed by Linus Torvalds
parent ca0aec0f7a
commit 3a291a20bd
2 changed files with 21 additions and 0 deletions

View File

@ -209,6 +209,7 @@ extern unsigned int nr_swapfiles;
extern struct swap_info_struct swap_info[];
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
extern swp_entry_t get_swap_page_of_type(int type);
extern int swap_duplicate(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);

View File

@ -211,6 +211,26 @@ noswap:
return (swp_entry_t) {0};
}
swp_entry_t get_swap_page_of_type(int type)
{
struct swap_info_struct *si;
pgoff_t offset;
spin_lock(&swap_lock);
si = swap_info + type;
if (si->flags & SWP_WRITEOK) {
nr_swap_pages--;
offset = scan_swap_map(si);
if (offset) {
spin_unlock(&swap_lock);
return swp_entry(type, offset);
}
nr_swap_pages++;
}
spin_unlock(&swap_lock);
return (swp_entry_t) {0};
}
static struct swap_info_struct * swap_info_get(swp_entry_t entry)
{
struct swap_info_struct * p;