Commit bb93e3a5 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Linus Torvalds
Browse files

[PATCH] block: add unlocked_ioctl support for block devices 



This patch allows block device drivers to convert their ioctl functions to
unlocked_ioctl() like character devices and other subsystems.  All
functions that were called with the BKL held before are still used that
way, but I would not be surprised if it could be removed from the ioctl
functions in drivers/block/ioctl.c themselves.

As a side note, I found that compat_blkdev_ioctl() acquires the BKL as
well, which looks like a bug.  I have checked that every user of
disk->fops->compat_ioctl() in the current git tree gets the BKL itself, so
it could easily be removed from compat_blkdev_ioctl().

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0d77e5a2

drivers/block/ioctl.c

+54 −20
Original line number Diff line number Diff line
@@ -133,11 +133,9 @@ static int put_u64(unsigned long arg, u64 val) 
	return put_user(val, (u64 __user *)arg);

}



int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,

			unsigned long arg)

static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,

				unsigned cmd, unsigned long arg)

{

	struct block_device *bdev = inode->i_bdev;

	struct gendisk *disk = bdev->bd_disk;

	struct backing_dev_info *bdi;

	int ret, n;
@@ -190,36 +188,72 @@ int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd, 
		return put_ulong(arg, bdev->bd_inode->i_size >> 9);

	case BLKGETSIZE64:

		return put_u64(arg, bdev->bd_inode->i_size);

	}

	return -ENOIOCTLCMD;

}



static int blkdev_driver_ioctl(struct inode *inode, struct file *file,

		struct gendisk *disk, unsigned cmd, unsigned long arg)

{

	int ret;

	if (disk->fops->unlocked_ioctl)

		return disk->fops->unlocked_ioctl(file, cmd, arg);



	if (disk->fops->ioctl) {

		lock_kernel();

		ret = disk->fops->ioctl(inode, file, cmd, arg);

		unlock_kernel();

		return ret;

	}



	return -ENOTTY;

}



int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,

			unsigned long arg)

{

	struct block_device *bdev = inode->i_bdev;

	struct gendisk *disk = bdev->bd_disk;

	int ret, n;



	switch(cmd) {

	case BLKFLSBUF:

		if (!capable(CAP_SYS_ADMIN))

			return -EACCES;

		if (disk->fops->ioctl) {

			ret = disk->fops->ioctl(inode, file, cmd, arg);



		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);

		/* -EINVAL to handle old uncorrected drivers */

		if (ret != -EINVAL && ret != -ENOTTY)

			return ret;

		}



		lock_kernel();

		fsync_bdev(bdev);

		invalidate_bdev(bdev, 0);

		unlock_kernel();

		return 0;



	case BLKROSET:

		if (disk->fops->ioctl) {

			ret = disk->fops->ioctl(inode, file, cmd, arg);

		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);

		/* -EINVAL to handle old uncorrected drivers */

		if (ret != -EINVAL && ret != -ENOTTY)

			return ret;

		}

		if (!capable(CAP_SYS_ADMIN))

			return -EACCES;

		if (get_user(n, (int __user *)(arg)))

			return -EFAULT;

		lock_kernel();

		set_device_ro(bdev, n);

		unlock_kernel();

		return 0;

	default:

		if (disk->fops->ioctl)

			return disk->fops->ioctl(inode, file, cmd, arg);

	}

	return -ENOTTY;



	lock_kernel();

	ret = blkdev_locked_ioctl(file, bdev, cmd, arg);

	unlock_kernel();

	if (ret != -ENOIOCTLCMD)

		return ret;



	return blkdev_driver_ioctl(inode, file, disk, cmd, arg);

}



/* Most of the generic ioctls are handled in the normal fallback path.

fs/block_dev.c

+2 −3
Original line number Diff line number Diff line
@@ -777,8 +777,7 @@ static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf, 
	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);

}



static int block_ioctl(struct inode *inode, struct file *file, unsigned cmd,

			unsigned long arg)

static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)

{

	return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);

}
@@ -803,7 +802,7 @@ struct file_operations def_blk_fops = { 
  	.aio_write	= blkdev_file_aio_write, 

	.mmap		= generic_file_mmap,

	.fsync		= block_fsync,

	.ioctl		= block_ioctl,

	.unlocked_ioctl	= block_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl	= compat_blkdev_ioctl,

#endif

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -884,6 +884,7 @@ struct block_device_operations { 
	int (*open) (struct inode *, struct file *);

	int (*release) (struct inode *, struct file *);

	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);

	long (*unlocked_ioctl) (struct file *, unsigned, unsigned long);

	long (*compat_ioctl) (struct file *, unsigned, unsigned long);

	int (*media_changed) (struct gendisk *);

	int (*revalidate_disk) (struct gendisk *);

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