[PATCH 12/21] mm: block device swap notification

[Peter Zijlstra]

Some block devices need to do some extra work when used as swap device.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
CC: James E.J. Bottomley <James.Bottomley@xxxxxxxxxxxx>
CC: Mike Christie <michaelc@xxxxxxxxxxx>
CC: Pavel Machek <pavel@xxxxxx>
---
 include/linux/fs.h |    1 +
 mm/swapfile.c      |    7 +++++++
 2 files changed, 8 insertions(+)

Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h
+++ linux-2.6/include/linux/fs.h
@@ -1017,6 +1017,7 @@ struct block_device_operations {
 	int (*media_changed) (struct gendisk *);
 	int (*revalidate_disk) (struct gendisk *);
 	int (*getgeo)(struct block_device *, struct hd_geometry *);
+	int (*swapdev)(struct gendisk *, int enable);
 	struct module *owner;
 };
 
Index: linux-2.6/mm/swapfile.c
===================================================================
--- linux-2.6.orig/mm/swapfile.c
+++ linux-2.6/mm/swapfile.c
@@ -1273,6 +1273,8 @@ asmlinkage long sys_swapoff(const char _
 	inode = mapping->host;
 	if (S_ISBLK(inode->i_mode)) {
 		struct block_device *bdev = I_BDEV(inode);
+		if (bdev->bd_disk->fops->swapdev)
+			bdev->bd_disk->fops->swapdev(bdev->bd_disk, 0);
 		set_blocksize(bdev, p->old_block_size);
 		bd_release(bdev);
 	} else {
@@ -1481,6 +1483,11 @@ asmlinkage long sys_swapdev(const char __
 		if (error < 0)
 			goto bad_swap;
 		p->bdev = bdev;
+		if (bdev->bd_disk->fops->swapdev) {
+			error = bdev->bd_disk->fops->swapdev(bdev->bd_disk, 1);
+			if (error < 0)
+				goto bad_swap;
+		}
 	} else if (S_ISREG(inode->i_mode)) {
 		p->bdev = inode->i_sb->s_bdev;
 		mutex_lock(&inode->i_mutex);

--
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