Commit aa129a22 authored by Milan Broz's avatar Milan Broz Committed by Linus Torvalds
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[PATCH] dm: support ioctls on mapped devices 



Extend the core device-mapper infrastructure to accept arbitrary ioctls on a
mapped device provided that it has exactly one target and it is capable of
supporting ioctls.

[We can't use unlocked_ioctl because we need 'inode': 'file' might be NULL.
Is it worth changing this?]

Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>

Arnd Bergmann <arnd@arndb.de> wrote:

> Am Wednesday 21 June 2006 21:31 schrieb Alasdair G Kergon:
> > static struct block_device_operations dm_blk_dops = {
> > .open = dm_blk_open,
> > .release = dm_blk_close,
> > +.ioctl = dm_blk_ioctl,
> > .getgeo = dm_blk_getgeo,
> > .owner = THIS_MODULE
>
> I guess this also needs a ->compat_ioctl method, otherwise it won't
> work for ioctl numbers that have a compat_ioctl implementation in the
> low-level device driver.

Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 70abac6e

drivers/md/dm.c

+41 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/idr.h>

#include <linux/hdreg.h>

#include <linux/blktrace_api.h>

#include <linux/smp_lock.h>



#define DM_MSG_PREFIX "core"
@@ -288,6 +289,45 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) 
	return dm_get_geometry(md, geo);

}



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

			unsigned int cmd, unsigned long arg)

{

	struct mapped_device *md;

	struct dm_table *map;

	struct dm_target *tgt;

	int r = -ENOTTY;



	/* We don't really need this lock, but we do need 'inode'. */

	unlock_kernel();



	md = inode->i_bdev->bd_disk->private_data;



	map = dm_get_table(md);



	if (!map || !dm_table_get_size(map))

		goto out;



	/* We only support devices that have a single target */

	if (dm_table_get_num_targets(map) != 1)

		goto out;



	tgt = dm_table_get_target(map, 0);



	if (dm_suspended(md)) {

		r = -EAGAIN;

		goto out;

	}



	if (tgt->type->ioctl)

		r = tgt->type->ioctl(tgt, inode, file, cmd, arg);



out:

	dm_table_put(map);



	lock_kernel();

	return r;

}



static inline struct dm_io *alloc_io(struct mapped_device *md)

{

	return mempool_alloc(md->io_pool, GFP_NOIO);
@@ -1377,6 +1417,7 @@ int dm_suspended(struct mapped_device *md) 
static struct block_device_operations dm_blk_dops = {

	.open = dm_blk_open,

	.release = dm_blk_close,

	.ioctl = dm_blk_ioctl,

	.getgeo = dm_blk_getgeo,

	.owner = THIS_MODULE

};

include/linux/device-mapper.h

+5 −0
Original line number Diff line number Diff line
@@ -64,6 +64,10 @@ typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, 


typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);



typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,

			    struct file *filp, unsigned int cmd,

			    unsigned long arg);



void dm_error(const char *message);



/*
@@ -91,6 +95,7 @@ struct target_type { 
	dm_resume_fn resume;

	dm_status_fn status;

	dm_message_fn message;

	dm_ioctl_fn ioctl;

};



struct io_restrictions {

include/linux/dm-ioctl.h

+1 −1
Original line number Diff line number Diff line
@@ -285,7 +285,7 @@ typedef char ioctl_struct[308]; 
#define DM_DEV_SET_GEOMETRY	_IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)



#define DM_VERSION_MAJOR	4

#define DM_VERSION_MINOR	7

#define DM_VERSION_MINOR	8

#define DM_VERSION_PATCHLEVEL	0

#define DM_VERSION_EXTRA	"-ioctl (2006-06-24)"

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