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Commit c336078b authored by Ben Hutchings's avatar Ben Hutchings Committed by Rafael J. Wysocki
Browse files

PM / Hibernate: Implement compat_ioctl for /dev/snapshot 

This allows uswsusp built for i386 to run on an x86_64 kernel (tested
with Debian package version 1.0+20110509-2).

References: http://bugs.debian.org/502816


Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 90363ddf

kernel/power/user.c

+64 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/swapops.h>

#include <linux/pm.h>

#include <linux/fs.h>

#include <linux/compat.h>

#include <linux/console.h>

#include <linux/cpu.h>

#include <linux/freezer.h>
@@ -380,6 +381,66 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, 
	return error;

}



#ifdef CONFIG_COMPAT



struct compat_resume_swap_area {

	compat_loff_t offset;

	u32 dev;

} __packed;



static long

snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));



	switch (cmd) {

	case SNAPSHOT_GET_IMAGE_SIZE:

	case SNAPSHOT_AVAIL_SWAP_SIZE:

	case SNAPSHOT_ALLOC_SWAP_PAGE: {

		compat_loff_t __user *uoffset = compat_ptr(arg);

		loff_t offset;

		mm_segment_t old_fs;

		int err;



		old_fs = get_fs();

		set_fs(KERNEL_DS);

		err = snapshot_ioctl(file, cmd, (unsigned long) &offset);

		set_fs(old_fs);

		if (!err && put_user(offset, uoffset))

			err = -EFAULT;

		return err;

	}



	case SNAPSHOT_CREATE_IMAGE:

		return snapshot_ioctl(file, cmd,

				      (unsigned long) compat_ptr(arg));



	case SNAPSHOT_SET_SWAP_AREA: {

		struct compat_resume_swap_area __user *u_swap_area =

			compat_ptr(arg);

		struct resume_swap_area swap_area;

		mm_segment_t old_fs;

		int err;



		err = get_user(swap_area.offset, &u_swap_area->offset);

		err |= get_user(swap_area.dev, &u_swap_area->dev);

		if (err)

			return -EFAULT;

		old_fs = get_fs();

		set_fs(KERNEL_DS);

		err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,

				     (unsigned long) &swap_area);

		set_fs(old_fs);

		return err;

	}



	default:

		return snapshot_ioctl(file, cmd, arg);

	}

}



#endif /* CONFIG_COMPAT */



static const struct file_operations snapshot_fops = {

	.open = snapshot_open,

	.release = snapshot_release,
@@ -387,6 +448,9 @@ static const struct file_operations snapshot_fops = { 
	.write = snapshot_write,

	.llseek = no_llseek,

	.unlocked_ioctl = snapshot_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl = snapshot_compat_ioctl,

#endif

};



static struct miscdevice snapshot_device = {