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authorNitin Gupta <ngupta@vflare.org>2010-05-17 11:02:43 +0530
committerGreg Kroah-Hartman <gregkh@suse.de>2010-05-18 15:07:52 -0700
commitb3a27d0529c6e5206f1b60f60263e3ecfd0d77cb (patch)
tree50ce5c6ce06ed700160491f2cd0e93d318ccc7fd /mm/swapfile.c
parentb27256439568950f30864ccecaeb6dfb588089d5 (diff)
downloadlinux-b3a27d0529c6e5206f1b60f60263e3ecfd0d77cb.tar.bz2
swap: Add swap slot free callback to block_device_operations
This callback is required when RAM based devices are used as swap disks. One such device is ramzswap which is used as compressed in-memory swap disk. For such devices, we need a callback as soon as a swap slot is no longer used to allow freeing memory allocated for this slot. Without this callback, stale data can quickly accumulate in memory defeating the whole purpose of such devices. Signed-off-by: Nitin Gupta <ngupta@vflare.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index ecb069e213d0..f5ccc476aa51 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -574,6 +574,7 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
/* free if no reference */
if (!usage) {
+ struct gendisk *disk = p->bdev->bd_disk;
if (offset < p->lowest_bit)
p->lowest_bit = offset;
if (offset > p->highest_bit)
@@ -583,6 +584,9 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
swap_list.next = p->type;
nr_swap_pages++;
p->inuse_pages--;
+ if ((p->flags & SWP_BLKDEV) &&
+ disk->fops->swap_slot_free_notify)
+ disk->fops->swap_slot_free_notify(p->bdev, offset);
}
return usage;