Commit 3a291a20 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds
Browse files

[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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ca0aec0f

include/linux/swap.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

mm/swapfile.c

+20 −0
Original line number Diff line number Diff line
@@ -211,6 +211,26 @@ swp_entry_t get_swap_page(void) 
	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;