block: remove pktcdvd driver

This driver has long outlived it's utility, and it's broken and unloved.
The main use case for this was direct mount with UDF of cd-rw drives
that required 32kb packets. It would collect writes into that size and
write them out in multiples of that. That's not a common use case
anymore, the world has moved on from those kinds of media. To make
matters worse, it's actively breaking setups where it's not even
required or useful.

Link: https://lore.kernel.org/linux-block/fxg6dksau4jsk3u5xldlyo2m7qgiux6vtdrz5rywseotsouqdv@urcrwz6qtd3r/
Link: https://lore.kernel.org/linux-block/[e-mail]/
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

Documentation/ABI/testing/debugfs-pktcdvd

···
-What:           /sys/kernel/debug/pktcdvd/pktcdvd[0-7]
-Date:           Oct. 2006
-KernelVersion:  2.6.20
-Contact:        Thomas Maier <[e-mail]>
-Description:
-
-The pktcdvd module (packet writing driver) creates
-these files in debugfs:
-
-/sys/kernel/debug/pktcdvd/pktcdvd[0-7]/
-
-    ====            ====== ====================================
-    info            0444   Lots of driver statistics and infos.
-    ====            ====== ====================================
-
-Example::
-
-    cat /sys/kernel/debug/pktcdvd/pktcdvd0/info

Documentation/ABI/testing/sysfs-class-pktcdvd

···
-sysfs interface
----------------
-The pktcdvd module (packet writing driver) creates the following files in the
-sysfs: (<devid> is in the format major:minor)
-
-What:		/sys/class/pktcdvd/add
-What:		/sys/class/pktcdvd/remove
-What:		/sys/class/pktcdvd/device_map
-Date:		Oct. 2006
-KernelVersion:	2.6.20
-Contact:	Thomas Maier <[e-mail]>
-Description:
-
-		==========	==============================================
-		add		(WO) Write a block device id (major:minor) to
-				create a new pktcdvd device and map it to the
-				block device.
-
-		remove		(WO) Write the pktcdvd device id (major:minor)
-				to remove the pktcdvd device.
-
-		device_map	(RO) Shows the device mapping in format:
-				pktcdvd[0-7] <pktdevid> <blkdevid>
-		==========	==============================================
-
-
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/dev
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/uevent
-Date:		Oct. 2006
-KernelVersion:	2.6.20
-Contact:	Thomas Maier <[e-mail]>
-Description:
-		dev:	(RO) Device id
-
-		uevent:	(WO) To send a uevent
-
-
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_started
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_finished
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_written
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read_gather
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/stat/reset
-Date:		Oct. 2006
-KernelVersion:	2.6.20
-Contact:	Thomas Maier <[e-mail]>
-Description:
-		packets_started:	(RO) Number of started packets.
-
-		packets_finished:	(RO) Number of finished packets.
-
-		kb_written:		(RO) kBytes written.
-
-		kb_read:		(RO) kBytes read.
-
-		kb_read_gather:		(RO) kBytes read to fill write packets.
-
-		reset:			(WO) Write any value to it to reset
-					pktcdvd device statistic values, like
-					bytes read/written.
-
-
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/size
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_off
-What:		/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_on
-Date:		Oct. 2006
-KernelVersion:	2.6.20
-Contact:	Thomas Maier <[e-mail]>
-Description:
-		==============	================================================
-		size		(RO) Contains the size of the bio write queue.
-
-		congestion_off	(RW) If bio write queue size is below this mark,
-				accept new bio requests from the block layer.
-
-		congestion_on	(RW) If bio write queue size is higher as this
-				mark, do no longer accept bio write requests
-				from the block layer and wait till the pktcdvd
-				device has processed enough bio's so that bio
-				write queue size is below congestion off mark.
-				A value of <= 0 disables congestion control.
-		==============	================================================
-
-
-Example:
---------
-To use the pktcdvd sysfs interface directly, you can do::
-
-    # create a new pktcdvd device mapped to /dev/hdc
-    echo "22:0" >/sys/class/pktcdvd/add
-    cat /sys/class/pktcdvd/device_map
-    # assuming device pktcdvd0 was created, look at stat's
-    cat /sys/class/pktcdvd/pktcdvd0/stat/kb_written
-    # print the device id of the mapped block device
-    fgrep pktcdvd0 /sys/class/pktcdvd/device_map
-    # remove device, using pktcdvd0 device id   253:0
-    echo "253:0" >/sys/class/pktcdvd/remove

Documentation/cdrom/packet-writing.rst

···
-==============
-Packet writing
-==============
-
-Getting started quick
----------------------
-
-- Select packet support in the block device section and UDF support in
-  the file system section.
-
-- Compile and install kernel and modules, reboot.
-
-- You need the udftools package (pktsetup, mkudffs, cdrwtool).
-  Download from https://github.com/pali/udftools
-
-- Grab a new CD-RW disc and format it (assuming CD-RW is hdc, substitute
-  as appropriate)::
-
-	# cdrwtool -d /dev/hdc -q
-
-- Setup your writer::
-
-	# pktsetup dev_name /dev/hdc
-
-- Now you can mount /dev/pktcdvd/dev_name and copy files to it. Enjoy::
-
-	# mount /dev/pktcdvd/dev_name /cdrom -t udf -o rw,noatime
-
-
-Packet writing for DVD-RW media
--------------------------------
-
-DVD-RW discs can be written to much like CD-RW discs if they are in
-the so called "restricted overwrite" mode. To put a disc in restricted
-overwrite mode, run::
-
-	# dvd+rw-format /dev/hdc
-
-You can then use the disc the same way you would use a CD-RW disc::
-
-	# pktsetup dev_name /dev/hdc
-	# mount /dev/pktcdvd/dev_name /cdrom -t udf -o rw,noatime
-
-
-Packet writing for DVD+RW media
--------------------------------
-
-According to the DVD+RW specification, a drive supporting DVD+RW discs
-shall implement "true random writes with 2KB granularity", which means
-that it should be possible to put any filesystem with a block size >=
-2KB on such a disc. For example, it should be possible to do::
-
-	# dvd+rw-format /dev/hdc   (only needed if the disc has never
-	                            been formatted)
-	# mkudffs /dev/hdc
-	# mount /dev/hdc /cdrom -t udf -o rw,noatime
-
-However, some drives don't follow the specification and expect the
-host to perform aligned writes at 32KB boundaries. Other drives do
-follow the specification, but suffer bad performance problems if the
-writes are not 32KB aligned.
-
-Both problems can be solved by using the pktcdvd driver, which always
-generates aligned writes::
-
-	# dvd+rw-format /dev/hdc
-	# pktsetup dev_name /dev/hdc
-	# mkudffs /dev/pktcdvd/dev_name
-	# mount /dev/pktcdvd/dev_name /cdrom -t udf -o rw,noatime
-
-
-Packet writing for DVD-RAM media
---------------------------------
-
-DVD-RAM discs are random writable, so using the pktcdvd driver is not
-necessary. However, using the pktcdvd driver can improve performance
-in the same way it does for DVD+RW media.
-
-
-Notes
------
-
-- CD-RW media can usually not be overwritten more than about 1000
-  times, so to avoid unnecessary wear on the media, you should always
-  use the noatime mount option.
-
-- Defect management (ie automatic remapping of bad sectors) has not
-  been implemented yet, so you are likely to get at least some
-  filesystem corruption if the disc wears out.
-
-- Since the pktcdvd driver makes the disc appear as a regular block
-  device with a 2KB block size, you can put any filesystem you like on
-  the disc. For example, run::
-
-	# /sbin/mke2fs /dev/pktcdvd/dev_name
-
-  to create an ext2 filesystem on the disc.
-
-
-Using the pktcdvd sysfs interface
----------------------------------
-
-Since Linux 2.6.20, the pktcdvd module has a sysfs interface
-and can be controlled by it. For example the "pktcdvd" tool uses
-this interface. (see http://tom.ist-im-web.de/linux/software/pktcdvd )
-
-"pktcdvd" works similar to "pktsetup", e.g.::
-
-	# pktcdvd -a dev_name /dev/hdc
-	# mkudffs /dev/pktcdvd/dev_name
-	# mount -t udf -o rw,noatime /dev/pktcdvd/dev_name /dvdram
-	# cp files /dvdram
-	# umount /dvdram
-	# pktcdvd -r dev_name
-
-
-For a description of the sysfs interface look into the file:
-
-  Documentation/ABI/testing/sysfs-class-pktcdvd
-
-
-Using the pktcdvd debugfs interface
------------------------------------
-
-To read pktcdvd device infos in human readable form, do::
-
-	# cat /sys/kernel/debug/pktcdvd/pktcdvd[0-7]/info
-
-For a description of the debugfs interface look into the file:
-
-  Documentation/ABI/testing/debugfs-pktcdvd
-
-
-
-Links
------
-
-See http://fy.chalmers.se/~appro/linux/DVD+RW/ for more information
-about DVD writing.

Documentation/userspace-api/ioctl/ioctl-number.rst

···
              include/linux/falloc.h,
              linux/fs.h,
 'X'   all    fs/ocfs2/ocfs_fs.h                                      conflict!
-'X'   01     linux/pktcdvd.h                                         conflict!
 'Z'   14-15  drivers/message/fusion/mptctl.h
 '['   00-3F  linux/usb/tmc.h                                         USB Test and Measurement Devices
                                                                      <mailto:[e-mail]>

MAINTAINERS

···
 F:	Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
 F:	drivers/input/keyboard/pinephone-keyboard.c
 
-PKTCDVD DRIVER
-M:	[e-mail]
-S:	Orphan
-F:	drivers/block/pktcdvd.c
-F:	include/linux/pktcdvd.h
-F:	include/uapi/linux/pktcdvd.h
-
 PLANTOWER PMS7003 AIR POLLUTION SENSOR DRIVER
 M:	Tomasz Duszynski <[e-mail]>
 S:	Maintained

drivers/block/Kconfig

···
 	  The default value is 4096 kilobytes. Only change this if you know
 	  what you are doing.
 
-config CDROM_PKTCDVD
-	tristate "Packet writing on CD/DVD media (DEPRECATED)"
-	depends on !UML
-	depends on SCSI
-	select CDROM
-	help
-	  Note: This driver is deprecated and will be removed from the
-	  kernel in the near future!
-
-	  If you have a CDROM/DVD drive that supports packet writing, say
-	  Y to include support. It should work with any MMC/Mt Fuji
-	  compliant ATAPI or SCSI drive, which is just about any newer
-	  DVD/CD writer.
-
-	  Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs
-	  is possible.
-	  DVD-RW disks must be in restricted overwrite mode.
-
-	  See the file <file:Documentation/cdrom/packet-writing.rst>
-	  for further information on the use of this driver.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called pktcdvd.
-
-config CDROM_PKTCDVD_BUFFERS
-	int "Free buffers for data gathering"
-	depends on CDROM_PKTCDVD
-	default "8"
-	help
-	  This controls the maximum number of active concurrent packets. More
-	  concurrent packets can increase write performance, but also require
-	  more memory. Each concurrent packet will require approximately 64Kb
-	  of non-swappable kernel memory, memory which will be allocated when
-	  a disc is opened for writing.
-
-config CDROM_PKTCDVD_WCACHE
-	bool "Enable write caching"
-	depends on CDROM_PKTCDVD
-	help
-	  If enabled, write caching will be set for the CD-R/W device. For now
-	  this option is dangerous unless the CD-RW media is known good, as we
-	  don't do deferred write error handling yet.
-
 config ATA_OVER_ETH
 	tristate "ATA over Ethernet support"
 	depends on NET

drivers/block/Makefile

···
 obj-$(CONFIG_N64CART)		+= n64cart.o
 obj-$(CONFIG_BLK_DEV_RAM)	+= brd.o
 obj-$(CONFIG_BLK_DEV_LOOP)	+= loop.o
-obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
 
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o

drivers/block/pktcdvd.c

···
-/*
- * Copyright (C) 2000 Jens Axboe <[e-mail]>
- * Copyright (C) 2001-2004 Peter Osterlund <[e-mail]>
- * Copyright (C) 2006 Thomas Maier <[e-mail]>
- *
- * May be copied or modified under the terms of the GNU General Public
- * License.  See linux/COPYING for more information.
- *
- * Packet writing layer for ATAPI and SCSI CD-RW, DVD+RW, DVD-RW and
- * DVD-RAM devices.
- *
- * Theory of operation:
- *
- * At the lowest level, there is the standard driver for the CD/DVD device,
- * such as drivers/scsi/sr.c. This driver can handle read and write requests,
- * but it doesn't know anything about the special restrictions that apply to
- * packet writing. One restriction is that write requests must be aligned to
- * packet boundaries on the physical media, and the size of a write request
- * must be equal to the packet size. Another restriction is that a
- * GPCMD_FLUSH_CACHE command has to be issued to the drive before a read
- * command, if the previous command was a write.
- *
- * The purpose of the packet writing driver is to hide these restrictions from
- * higher layers, such as file systems, and present a block device that can be
- * randomly read and written using 2kB-sized blocks.
- *
- * The lowest layer in the packet writing driver is the packet I/O scheduler.
- * Its data is defined by the struct packet_iosched and includes two bio
- * queues with pending read and write requests. These queues are processed
- * by the pkt_iosched_process_queue() function. The write requests in this
- * queue are already properly aligned and sized. This layer is responsible for
- * issuing the flush cache commands and scheduling the I/O in a good order.
- *
- * The next layer transforms unaligned write requests to aligned writes. This
- * transformation requires reading missing pieces of data from the underlying
- * block device, assembling the pieces to full packets and queuing them to the
- * packet I/O scheduler.
- *
- * At the top layer there is a custom ->submit_bio function that forwards
- * read requests directly to the iosched queue and puts write requests in the
- * unaligned write queue. A kernel thread performs the necessary read
- * gathering to convert the unaligned writes to aligned writes and then feeds
- * them to the packet I/O scheduler.
- *
- *************************************************************************/
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/backing-dev.h>
-#include <linux/compat.h>
-#include <linux/debugfs.h>
-#include <linux/device.h>
-#include <linux/errno.h>
-#include <linux/file.h>
-#include <linux/freezer.h>
-#include <linux/kernel.h>
-#include <linux/kthread.h>
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/nospec.h>
-#include <linux/pktcdvd.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/types.h>
-#include <linux/uaccess.h>
-
-#include <scsi/scsi.h>
-#include <scsi/scsi_cmnd.h>
-#include <scsi/scsi_ioctl.h>
-
-#include <linux/unaligned.h>
-
-#define DRIVER_NAME	"pktcdvd"
-
-#define MAX_SPEED 0xffff
-
-static DEFINE_MUTEX(pktcdvd_mutex);
-static struct pktcdvd_device *pkt_devs[MAX_WRITERS];
-static struct proc_dir_entry *pkt_proc;
-static int pktdev_major;
-static int write_congestion_on  = PKT_WRITE_CONGESTION_ON;
-static int write_congestion_off = PKT_WRITE_CONGESTION_OFF;
-static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */
-static mempool_t psd_pool;
-static struct bio_set pkt_bio_set;
-
-/* /sys/class/pktcdvd */
-static struct class	class_pktcdvd;
-static struct dentry	*pkt_debugfs_root = NULL; /* /sys/kernel/debug/pktcdvd */
-
-/* forward declaration */
-static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev);
-static int pkt_remove_dev(dev_t pkt_dev);
-
-static sector_t get_zone(sector_t sector, struct pktcdvd_device *pd)
-{
-	return (sector + pd->offset) & ~(sector_t)(pd->settings.size - 1);
-}
-
-/**********************************************************
- * sysfs interface for pktcdvd
- * by (C) 2006  Thomas Maier <[e-mail]>
- 
-  /sys/class/pktcdvd/pktcdvd[0-7]/
-                     stat/reset
-                     stat/packets_started
-                     stat/packets_finished
-                     stat/kb_written
-                     stat/kb_read
-                     stat/kb_read_gather
-                     write_queue/size
-                     write_queue/congestion_off
-                     write_queue/congestion_on
- **********************************************************/
-
-static ssize_t packets_started_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	return sysfs_emit(buf, "%lu\n", pd->stats.pkt_started);
-}
-static DEVICE_ATTR_RO(packets_started);
-
-static ssize_t packets_finished_show(struct device *dev,
-				     struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	return sysfs_emit(buf, "%lu\n", pd->stats.pkt_ended);
-}
-static DEVICE_ATTR_RO(packets_finished);
-
-static ssize_t kb_written_show(struct device *dev,
-			       struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	return sysfs_emit(buf, "%lu\n", pd->stats.secs_w >> 1);
-}
-static DEVICE_ATTR_RO(kb_written);
-
-static ssize_t kb_read_show(struct device *dev,
-			    struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	return sysfs_emit(buf, "%lu\n", pd->stats.secs_r >> 1);
-}
-static DEVICE_ATTR_RO(kb_read);
-
-static ssize_t kb_read_gather_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	return sysfs_emit(buf, "%lu\n", pd->stats.secs_rg >> 1);
-}
-static DEVICE_ATTR_RO(kb_read_gather);
-
-static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
-			   const char *buf, size_t len)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-
-	if (len > 0) {
-		pd->stats.pkt_started = 0;
-		pd->stats.pkt_ended = 0;
-		pd->stats.secs_w = 0;
-		pd->stats.secs_rg = 0;
-		pd->stats.secs_r = 0;
-	}
-	return len;
-}
-static DEVICE_ATTR_WO(reset);
-
-static struct attribute *pkt_stat_attrs[] = {
-	&dev_attr_packets_finished.attr,
-	&dev_attr_packets_started.attr,
-	&dev_attr_kb_read.attr,
-	&dev_attr_kb_written.attr,
-	&dev_attr_kb_read_gather.attr,
-	&dev_attr_reset.attr,
-	NULL,
-};
-
-static const struct attribute_group pkt_stat_group = {
-	.name = "stat",
-	.attrs = pkt_stat_attrs,
-};
-
-static ssize_t size_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-	int n;
-
-	spin_lock(&pd->lock);
-	n = sysfs_emit(buf, "%d\n", pd->bio_queue_size);
-	spin_unlock(&pd->lock);
-	return n;
-}
-static DEVICE_ATTR_RO(size);
-
-static void init_write_congestion_marks(int* lo, int* hi)
-{
-	if (*hi > 0) {
-		*hi = max(*hi, 500);
-		*hi = min(*hi, 1000000);
-		if (*lo <= 0)
-			*lo = *hi - 100;
-		else {
-			*lo = min(*lo, *hi - 100);
-			*lo = max(*lo, 100);
-		}
-	} else {
-		*hi = -1;
-		*lo = -1;
-	}
-}
-
-static ssize_t congestion_off_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-	int n;
-
-	spin_lock(&pd->lock);
-	n = sysfs_emit(buf, "%d\n", pd->write_congestion_off);
-	spin_unlock(&pd->lock);
-	return n;
-}
-
-static ssize_t congestion_off_store(struct device *dev,
-				    struct device_attribute *attr,
-				    const char *buf, size_t len)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-	int val, ret;
-
-	ret = kstrtoint(buf, 10, &val);
-	if (ret)
-		return ret;
-
-	spin_lock(&pd->lock);
-	pd->write_congestion_off = val;
-	init_write_congestion_marks(&pd->write_congestion_off, &pd->write_congestion_on);
-	spin_unlock(&pd->lock);
-	return len;
-}
-static DEVICE_ATTR_RW(congestion_off);
-
-static ssize_t congestion_on_show(struct device *dev,
-				  struct device_attribute *attr, char *buf)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-	int n;
-
-	spin_lock(&pd->lock);
-	n = sysfs_emit(buf, "%d\n", pd->write_congestion_on);
-	spin_unlock(&pd->lock);
-	return n;
-}
-
-static ssize_t congestion_on_store(struct device *dev,
-				   struct device_attribute *attr,
-				   const char *buf, size_t len)
-{
-	struct pktcdvd_device *pd = dev_get_drvdata(dev);
-	int val, ret;
-
-	ret = kstrtoint(buf, 10, &val);
-	if (ret)
-		return ret;
-
-	spin_lock(&pd->lock);
-	pd->write_congestion_on = val;
-	init_write_congestion_marks(&pd->write_congestion_off, &pd->write_congestion_on);
-	spin_unlock(&pd->lock);
-	return len;
-}
-static DEVICE_ATTR_RW(congestion_on);
-
-static struct attribute *pkt_wq_attrs[] = {
-	&dev_attr_congestion_on.attr,
-	&dev_attr_congestion_off.attr,
-	&dev_attr_size.attr,
-	NULL,
-};
-
-static const struct attribute_group pkt_wq_group = {
-	.name = "write_queue",
-	.attrs = pkt_wq_attrs,
-};
-
-static const struct attribute_group *pkt_groups[] = {
-	&pkt_stat_group,
-	&pkt_wq_group,
-	NULL,
-};
-
-static void pkt_sysfs_dev_new(struct pktcdvd_device *pd)
-{
-	if (class_is_registered(&class_pktcdvd)) {
-		pd->dev = device_create_with_groups(&class_pktcdvd, NULL,
-						    MKDEV(0, 0), pd, pkt_groups,
-						    "%s", pd->disk->disk_name);
-		if (IS_ERR(pd->dev))
-			pd->dev = NULL;
-	}
-}
-
-static void pkt_sysfs_dev_remove(struct pktcdvd_device *pd)
-{
-	if (class_is_registered(&class_pktcdvd))
-		device_unregister(pd->dev);
-}
-
-
-/********************************************************************
-  /sys/class/pktcdvd/
-                     add            map block device
-                     remove         unmap packet dev
-                     device_map     show mappings
- *******************************************************************/
-
-static ssize_t device_map_show(const struct class *c, const struct class_attribute *attr,
-			       char *data)
-{
-	int n = 0;
-	int idx;
-	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
-	for (idx = 0; idx < MAX_WRITERS; idx++) {
-		struct pktcdvd_device *pd = pkt_devs[idx];
-		if (!pd)
-			continue;
-		n += sysfs_emit_at(data, n, "%s %u:%u %u:%u\n",
-			pd->disk->disk_name,
-			MAJOR(pd->pkt_dev), MINOR(pd->pkt_dev),
-			MAJOR(file_bdev(pd->bdev_file)->bd_dev),
-			MINOR(file_bdev(pd->bdev_file)->bd_dev));
-	}
-	mutex_unlock(&ctl_mutex);
-	return n;
-}
-static CLASS_ATTR_RO(device_map);
-
-static ssize_t add_store(const struct class *c, const struct class_attribute *attr,
-			 const char *buf, size_t count)
-{
-	unsigned int major, minor;
-
-	if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
-		/* pkt_setup_dev() expects caller to hold reference to self */
-		if (!try_module_get(THIS_MODULE))
-			return -ENODEV;
-
-		pkt_setup_dev(MKDEV(major, minor), NULL);
-
-		module_put(THIS_MODULE);
-
-		return count;
-	}
-
-	return -EINVAL;
-}
-static CLASS_ATTR_WO(add);
-
-static ssize_t remove_store(const struct class *c, const struct class_attribute *attr,
-			    const char *buf, size_t count)
-{
-	unsigned int major, minor;
-	if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
-		pkt_remove_dev(MKDEV(major, minor));
-		return count;
-	}
-	return -EINVAL;
-}
-static CLASS_ATTR_WO(remove);
-
-static struct attribute *class_pktcdvd_attrs[] = {
-	&class_attr_add.attr,
-	&class_attr_remove.attr,
-	&class_attr_device_map.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(class_pktcdvd);
-
-static struct class class_pktcdvd = {
-	.name		= DRIVER_NAME,
-	.class_groups	= class_pktcdvd_groups,
-};
-
-static int pkt_sysfs_init(void)
-{
-	/*
-	 * create control files in sysfs
-	 * /sys/class/pktcdvd/...
-	 */
-	return class_register(&class_pktcdvd);
-}
-
-static void pkt_sysfs_cleanup(void)
-{
-	class_unregister(&class_pktcdvd);
-}
-
-/********************************************************************
-  entries in debugfs
-
-  /sys/kernel/debug/pktcdvd[0-7]/
-			info
-
- *******************************************************************/
-
-static void pkt_count_states(struct pktcdvd_device *pd, int *states)
-{
-	struct packet_data *pkt;
-	int i;
-
-	for (i = 0; i < PACKET_NUM_STATES; i++)
-		states[i] = 0;
-
-	spin_lock(&pd->cdrw.active_list_lock);
-	list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-		states[pkt->state]++;
-	}
-	spin_unlock(&pd->cdrw.active_list_lock);
-}
-
-static int pkt_seq_show(struct seq_file *m, void *p)
-{
-	struct pktcdvd_device *pd = m->private;
-	char *msg;
-	int states[PACKET_NUM_STATES];
-
-	seq_printf(m, "Writer %s mapped to %pg:\n", pd->disk->disk_name,
-		   file_bdev(pd->bdev_file));
-
-	seq_printf(m, "\nSettings:\n");
-	seq_printf(m, "\tpacket size:\t\t%dkB\n", pd->settings.size / 2);
-
-	if (pd->settings.write_type == 0)
-		msg = "Packet";
-	else
-		msg = "Unknown";
-	seq_printf(m, "\twrite type:\t\t%s\n", msg);
-
-	seq_printf(m, "\tpacket type:\t\t%s\n", pd->settings.fp ? "Fixed" : "Variable");
-	seq_printf(m, "\tlink loss:\t\t%d\n", pd->settings.link_loss);
-
-	seq_printf(m, "\ttrack mode:\t\t%d\n", pd->settings.track_mode);
-
-	if (pd->settings.block_mode == PACKET_BLOCK_MODE1)
-		msg = "Mode 1";
-	else if (pd->settings.block_mode == PACKET_BLOCK_MODE2)
-		msg = "Mode 2";
-	else
-		msg = "Unknown";
-	seq_printf(m, "\tblock mode:\t\t%s\n", msg);
-
-	seq_printf(m, "\nStatistics:\n");
-	seq_printf(m, "\tpackets started:\t%lu\n", pd->stats.pkt_started);
-	seq_printf(m, "\tpackets ended:\t\t%lu\n", pd->stats.pkt_ended);
-	seq_printf(m, "\twritten:\t\t%lukB\n", pd->stats.secs_w >> 1);
-	seq_printf(m, "\tread gather:\t\t%lukB\n", pd->stats.secs_rg >> 1);
-	seq_printf(m, "\tread:\t\t\t%lukB\n", pd->stats.secs_r >> 1);
-
-	seq_printf(m, "\nMisc:\n");
-	seq_printf(m, "\treference count:\t%d\n", pd->refcnt);
-	seq_printf(m, "\tflags:\t\t\t0x%lx\n", pd->flags);
-	seq_printf(m, "\tread speed:\t\t%ukB/s\n", pd->read_speed);
-	seq_printf(m, "\twrite speed:\t\t%ukB/s\n", pd->write_speed);
-	seq_printf(m, "\tstart offset:\t\t%lu\n", pd->offset);
-	seq_printf(m, "\tmode page offset:\t%u\n", pd->mode_offset);
-
-	seq_printf(m, "\nQueue state:\n");
-	seq_printf(m, "\tbios queued:\t\t%d\n", pd->bio_queue_size);
-	seq_printf(m, "\tbios pending:\t\t%d\n", atomic_read(&pd->cdrw.pending_bios));
-	seq_printf(m, "\tcurrent sector:\t\t0x%llx\n", pd->current_sector);
-
-	pkt_count_states(pd, states);
-	seq_printf(m, "\tstate:\t\t\ti:%d ow:%d rw:%d ww:%d rec:%d fin:%d\n",
-		   states[0], states[1], states[2], states[3], states[4], states[5]);
-
-	seq_printf(m, "\twrite congestion marks:\toff=%d on=%d\n",
-			pd->write_congestion_off,
-			pd->write_congestion_on);
-	return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(pkt_seq);
-
-static void pkt_debugfs_dev_new(struct pktcdvd_device *pd)
-{
-	if (!pkt_debugfs_root)
-		return;
-	pd->dfs_d_root = debugfs_create_dir(pd->disk->disk_name, pkt_debugfs_root);
-
-	pd->dfs_f_info = debugfs_create_file("info", 0444, pd->dfs_d_root,
-					     pd, &pkt_seq_fops);
-}
-
-static void pkt_debugfs_dev_remove(struct pktcdvd_device *pd)
-{
-	if (!pkt_debugfs_root)
-		return;
-	debugfs_remove(pd->dfs_f_info);
-	debugfs_remove(pd->dfs_d_root);
-	pd->dfs_f_info = NULL;
-	pd->dfs_d_root = NULL;
-}
-
-static void pkt_debugfs_init(void)
-{
-	pkt_debugfs_root = debugfs_create_dir(DRIVER_NAME, NULL);
-}
-
-static void pkt_debugfs_cleanup(void)
-{
-	debugfs_remove(pkt_debugfs_root);
-	pkt_debugfs_root = NULL;
-}
-
-/* ----------------------------------------------------------*/
-
-
-static void pkt_bio_finished(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	BUG_ON(atomic_read(&pd->cdrw.pending_bios) <= 0);
-	if (atomic_dec_and_test(&pd->cdrw.pending_bios)) {
-		dev_dbg(ddev, "queue empty\n");
-		atomic_set(&pd->iosched.attention, 1);
-		wake_up(&pd->wqueue);
-	}
-}
-
-/*
- * Allocate a packet_data struct
- */
-static struct packet_data *pkt_alloc_packet_data(int frames)
-{
-	int i;
-	struct packet_data *pkt;
-
-	pkt = kzalloc(sizeof(struct packet_data), GFP_KERNEL);
-	if (!pkt)
-		goto no_pkt;
-
-	pkt->frames = frames;
-	pkt->w_bio = bio_kmalloc(frames, GFP_KERNEL);
-	if (!pkt->w_bio)
-		goto no_bio;
-
-	for (i = 0; i < frames / FRAMES_PER_PAGE; i++) {
-		pkt->pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
-		if (!pkt->pages[i])
-			goto no_page;
-	}
-
-	spin_lock_init(&pkt->lock);
-	bio_list_init(&pkt->orig_bios);
-
-	for (i = 0; i < frames; i++) {
-		pkt->r_bios[i] = bio_kmalloc(1, GFP_KERNEL);
-		if (!pkt->r_bios[i])
-			goto no_rd_bio;
-	}
-
-	return pkt;
-
-no_rd_bio:
-	for (i = 0; i < frames; i++)
-		kfree(pkt->r_bios[i]);
-no_page:
-	for (i = 0; i < frames / FRAMES_PER_PAGE; i++)
-		if (pkt->pages[i])
-			__free_page(pkt->pages[i]);
-	kfree(pkt->w_bio);
-no_bio:
-	kfree(pkt);
-no_pkt:
-	return NULL;
-}
-
-/*
- * Free a packet_data struct
- */
-static void pkt_free_packet_data(struct packet_data *pkt)
-{
-	int i;
-
-	for (i = 0; i < pkt->frames; i++)
-		kfree(pkt->r_bios[i]);
-	for (i = 0; i < pkt->frames / FRAMES_PER_PAGE; i++)
-		__free_page(pkt->pages[i]);
-	kfree(pkt->w_bio);
-	kfree(pkt);
-}
-
-static void pkt_shrink_pktlist(struct pktcdvd_device *pd)
-{
-	struct packet_data *pkt, *next;
-
-	BUG_ON(!list_empty(&pd->cdrw.pkt_active_list));
-
-	list_for_each_entry_safe(pkt, next, &pd->cdrw.pkt_free_list, list) {
-		pkt_free_packet_data(pkt);
-	}
-	INIT_LIST_HEAD(&pd->cdrw.pkt_free_list);
-}
-
-static int pkt_grow_pktlist(struct pktcdvd_device *pd, int nr_packets)
-{
-	struct packet_data *pkt;
-
-	BUG_ON(!list_empty(&pd->cdrw.pkt_free_list));
-
-	while (nr_packets > 0) {
-		pkt = pkt_alloc_packet_data(pd->settings.size >> 2);
-		if (!pkt) {
-			pkt_shrink_pktlist(pd);
-			return 0;
-		}
-		pkt->id = nr_packets;
-		pkt->pd = pd;
-		list_add(&pkt->list, &pd->cdrw.pkt_free_list);
-		nr_packets--;
-	}
-	return 1;
-}
-
-static inline struct pkt_rb_node *pkt_rbtree_next(struct pkt_rb_node *node)
-{
-	struct rb_node *n = rb_next(&node->rb_node);
-	if (!n)
-		return NULL;
-	return rb_entry(n, struct pkt_rb_node, rb_node);
-}
-
-static void pkt_rbtree_erase(struct pktcdvd_device *pd, struct pkt_rb_node *node)
-{
-	rb_erase(&node->rb_node, &pd->bio_queue);
-	mempool_free(node, &pd->rb_pool);
-	pd->bio_queue_size--;
-	BUG_ON(pd->bio_queue_size < 0);
-}
-
-/*
- * Find the first node in the pd->bio_queue rb tree with a starting sector >= s.
- */
-static struct pkt_rb_node *pkt_rbtree_find(struct pktcdvd_device *pd, sector_t s)
-{
-	struct rb_node *n = pd->bio_queue.rb_node;
-	struct rb_node *next;
-	struct pkt_rb_node *tmp;
-
-	if (!n) {
-		BUG_ON(pd->bio_queue_size > 0);
-		return NULL;
-	}
-
-	for (;;) {
-		tmp = rb_entry(n, struct pkt_rb_node, rb_node);
-		if (s <= tmp->bio->bi_iter.bi_sector)
-			next = n->rb_left;
-		else
-			next = n->rb_right;
-		if (!next)
-			break;
-		n = next;
-	}
-
-	if (s > tmp->bio->bi_iter.bi_sector) {
-		tmp = pkt_rbtree_next(tmp);
-		if (!tmp)
-			return NULL;
-	}
-	BUG_ON(s > tmp->bio->bi_iter.bi_sector);
-	return tmp;
-}
-
-/*
- * Insert a node into the pd->bio_queue rb tree.
- */
-static void pkt_rbtree_insert(struct pktcdvd_device *pd, struct pkt_rb_node *node)
-{
-	struct rb_node **p = &pd->bio_queue.rb_node;
-	struct rb_node *parent = NULL;
-	sector_t s = node->bio->bi_iter.bi_sector;
-	struct pkt_rb_node *tmp;
-
-	while (*p) {
-		parent = *p;
-		tmp = rb_entry(parent, struct pkt_rb_node, rb_node);
-		if (s < tmp->bio->bi_iter.bi_sector)
-			p = &(*p)->rb_left;
-		else
-			p = &(*p)->rb_right;
-	}
-	rb_link_node(&node->rb_node, parent, p);
-	rb_insert_color(&node->rb_node, &pd->bio_queue);
-	pd->bio_queue_size++;
-}
-
-/*
- * Send a packet_command to the underlying block device and
- * wait for completion.
- */
-static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *cgc)
-{
-	struct request_queue *q = bdev_get_queue(file_bdev(pd->bdev_file));
-	struct scsi_cmnd *scmd;
-	struct request *rq;
-	int ret = 0;
-
-	rq = scsi_alloc_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
-			     REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
-	if (IS_ERR(rq))
-		return PTR_ERR(rq);
-	scmd = blk_mq_rq_to_pdu(rq);
-
-	if (cgc->buflen) {
-		ret = blk_rq_map_kern(rq, cgc->buffer, cgc->buflen,
-				      GFP_NOIO);
-		if (ret)
-			goto out;
-	}
-
-	scmd->cmd_len = COMMAND_SIZE(cgc->cmd[0]);
-	memcpy(scmd->cmnd, cgc->cmd, CDROM_PACKET_SIZE);
-
-	rq->timeout = 60*HZ;
-	if (cgc->quiet)
-		rq->rq_flags |= RQF_QUIET;
-
-	blk_execute_rq(rq, false);
-	if (scmd->result)
-		ret = -EIO;
-out:
-	blk_mq_free_request(rq);
-	return ret;
-}
-
-static const char *sense_key_string(__u8 index)
-{
-	static const char * const info[] = {
-		"No sense", "Recovered error", "Not ready",
-		"Medium error", "Hardware error", "Illegal request",
-		"Unit attention", "Data protect", "Blank check",
-	};
-
-	return index < ARRAY_SIZE(info) ? info[index] : "INVALID";
-}
-
-/*
- * A generic sense dump / resolve mechanism should be implemented across
- * all ATAPI + SCSI devices.
- */
-static void pkt_dump_sense(struct pktcdvd_device *pd,
-			   struct packet_command *cgc)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct scsi_sense_hdr *sshdr = cgc->sshdr;
-
-	if (sshdr)
-		dev_err(ddev, "%*ph - sense %02x.%02x.%02x (%s)\n",
-			CDROM_PACKET_SIZE, cgc->cmd,
-			sshdr->sense_key, sshdr->asc, sshdr->ascq,
-			sense_key_string(sshdr->sense_key));
-	else
-		dev_err(ddev, "%*ph - no sense\n", CDROM_PACKET_SIZE, cgc->cmd);
-}
-
-/*
- * flush the drive cache to media
- */
-static int pkt_flush_cache(struct pktcdvd_device *pd)
-{
-	struct packet_command cgc;
-
-	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
-	cgc.cmd[0] = GPCMD_FLUSH_CACHE;
-	cgc.quiet = 1;
-
-	/*
-	 * the IMMED bit -- we default to not setting it, although that
-	 * would allow a much faster close, this is safer
-	 */
-#if 0
-	cgc.cmd[1] = 1 << 1;
-#endif
-	return pkt_generic_packet(pd, &cgc);
-}
-
-/*
- * speed is given as the normal factor, e.g. 4 for 4x
- */
-static noinline_for_stack int pkt_set_speed(struct pktcdvd_device *pd,
-				unsigned write_speed, unsigned read_speed)
-{
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	int ret;
-
-	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
-	cgc.sshdr = &sshdr;
-	cgc.cmd[0] = GPCMD_SET_SPEED;
-	put_unaligned_be16(read_speed, &cgc.cmd[2]);
-	put_unaligned_be16(write_speed, &cgc.cmd[4]);
-
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret)
-		pkt_dump_sense(pd, &cgc);
-
-	return ret;
-}
-
-/*
- * Queue a bio for processing by the low-level CD device. Must be called
- * from process context.
- */
-static void pkt_queue_bio(struct pktcdvd_device *pd, struct bio *bio)
-{
-	/*
-	 * Some CDRW drives can not handle writes larger than one packet,
-	 * even if the size is a multiple of the packet size.
-	 */
-	bio->bi_opf |= REQ_NOMERGE;
-
-	spin_lock(&pd->iosched.lock);
-	if (bio_data_dir(bio) == READ)
-		bio_list_add(&pd->iosched.read_queue, bio);
-	else
-		bio_list_add(&pd->iosched.write_queue, bio);
-	spin_unlock(&pd->iosched.lock);
-
-	atomic_set(&pd->iosched.attention, 1);
-	wake_up(&pd->wqueue);
-}
-
-/*
- * Process the queued read/write requests. This function handles special
- * requirements for CDRW drives:
- * - A cache flush command must be inserted before a read request if the
- *   previous request was a write.
- * - Switching between reading and writing is slow, so don't do it more often
- *   than necessary.
- * - Optimize for throughput at the expense of latency. This means that streaming
- *   writes will never be interrupted by a read, but if the drive has to seek
- *   before the next write, switch to reading instead if there are any pending
- *   read requests.
- * - Set the read speed according to current usage pattern. When only reading
- *   from the device, it's best to use the highest possible read speed, but
- *   when switching often between reading and writing, it's better to have the
- *   same read and write speeds.
- */
-static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	if (atomic_read(&pd->iosched.attention) == 0)
-		return;
-	atomic_set(&pd->iosched.attention, 0);
-
-	for (;;) {
-		struct bio *bio;
-		int reads_queued, writes_queued;
-
-		spin_lock(&pd->iosched.lock);
-		reads_queued = !bio_list_empty(&pd->iosched.read_queue);
-		writes_queued = !bio_list_empty(&pd->iosched.write_queue);
-		spin_unlock(&pd->iosched.lock);
-
-		if (!reads_queued && !writes_queued)
-			break;
-
-		if (pd->iosched.writing) {
-			int need_write_seek = 1;
-			spin_lock(&pd->iosched.lock);
-			bio = bio_list_peek(&pd->iosched.write_queue);
-			spin_unlock(&pd->iosched.lock);
-			if (bio && (bio->bi_iter.bi_sector ==
-				    pd->iosched.last_write))
-				need_write_seek = 0;
-			if (need_write_seek && reads_queued) {
-				if (atomic_read(&pd->cdrw.pending_bios) > 0) {
-					dev_dbg(ddev, "write, waiting\n");
-					break;
-				}
-				pkt_flush_cache(pd);
-				pd->iosched.writing = 0;
-			}
-		} else {
-			if (!reads_queued && writes_queued) {
-				if (atomic_read(&pd->cdrw.pending_bios) > 0) {
-					dev_dbg(ddev, "read, waiting\n");
-					break;
-				}
-				pd->iosched.writing = 1;
-			}
-		}
-
-		spin_lock(&pd->iosched.lock);
-		if (pd->iosched.writing)
-			bio = bio_list_pop(&pd->iosched.write_queue);
-		else
-			bio = bio_list_pop(&pd->iosched.read_queue);
-		spin_unlock(&pd->iosched.lock);
-
-		if (!bio)
-			continue;
-
-		if (bio_data_dir(bio) == READ)
-			pd->iosched.successive_reads +=
-				bio->bi_iter.bi_size >> 10;
-		else {
-			pd->iosched.successive_reads = 0;
-			pd->iosched.last_write = bio_end_sector(bio);
-		}
-		if (pd->iosched.successive_reads >= HI_SPEED_SWITCH) {
-			if (pd->read_speed == pd->write_speed) {
-				pd->read_speed = MAX_SPEED;
-				pkt_set_speed(pd, pd->write_speed, pd->read_speed);
-			}
-		} else {
-			if (pd->read_speed != pd->write_speed) {
-				pd->read_speed = pd->write_speed;
-				pkt_set_speed(pd, pd->write_speed, pd->read_speed);
-			}
-		}
-
-		atomic_inc(&pd->cdrw.pending_bios);
-		submit_bio_noacct(bio);
-	}
-}
-
-/*
- * Special care is needed if the underlying block device has a small
- * max_phys_segments value.
- */
-static int pkt_set_segment_merging(struct pktcdvd_device *pd, struct request_queue *q)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	if ((pd->settings.size << 9) / CD_FRAMESIZE <= queue_max_segments(q)) {
-		/*
-		 * The cdrom device can handle one segment/frame
-		 */
-		clear_bit(PACKET_MERGE_SEGS, &pd->flags);
-		return 0;
-	}
-
-	if ((pd->settings.size << 9) / PAGE_SIZE <= queue_max_segments(q)) {
-		/*
-		 * We can handle this case at the expense of some extra memory
-		 * copies during write operations
-		 */
-		set_bit(PACKET_MERGE_SEGS, &pd->flags);
-		return 0;
-	}
-
-	dev_err(ddev, "cdrom max_phys_segments too small\n");
-	return -EIO;
-}
-
-static void pkt_end_io_read(struct bio *bio)
-{
-	struct packet_data *pkt = bio->bi_private;
-	struct pktcdvd_device *pd = pkt->pd;
-	BUG_ON(!pd);
-
-	dev_dbg(disk_to_dev(pd->disk), "bio=%p sec0=%llx sec=%llx err=%d\n",
-		bio, pkt->sector, bio->bi_iter.bi_sector, bio->bi_status);
-
-	if (bio->bi_status)
-		atomic_inc(&pkt->io_errors);
-	bio_uninit(bio);
-	if (atomic_dec_and_test(&pkt->io_wait)) {
-		atomic_inc(&pkt->run_sm);
-		wake_up(&pd->wqueue);
-	}
-	pkt_bio_finished(pd);
-}
-
-static void pkt_end_io_packet_write(struct bio *bio)
-{
-	struct packet_data *pkt = bio->bi_private;
-	struct pktcdvd_device *pd = pkt->pd;
-	BUG_ON(!pd);
-
-	dev_dbg(disk_to_dev(pd->disk), "id=%d, err=%d\n", pkt->id, bio->bi_status);
-
-	pd->stats.pkt_ended++;
-
-	bio_uninit(bio);
-	pkt_bio_finished(pd);
-	atomic_dec(&pkt->io_wait);
-	atomic_inc(&pkt->run_sm);
-	wake_up(&pd->wqueue);
-}
-
-/*
- * Schedule reads for the holes in a packet
- */
-static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	int frames_read = 0;
-	struct bio *bio;
-	int f;
-	char written[PACKET_MAX_SIZE];
-
-	BUG_ON(bio_list_empty(&pkt->orig_bios));
-
-	atomic_set(&pkt->io_wait, 0);
-	atomic_set(&pkt->io_errors, 0);
-
-	/*
-	 * Figure out which frames we need to read before we can write.
-	 */
-	memset(written, 0, sizeof(written));
-	spin_lock(&pkt->lock);
-	bio_list_for_each(bio, &pkt->orig_bios) {
-		int first_frame = (bio->bi_iter.bi_sector - pkt->sector) /
-			(CD_FRAMESIZE >> 9);
-		int num_frames = bio->bi_iter.bi_size / CD_FRAMESIZE;
-		pd->stats.secs_w += num_frames * (CD_FRAMESIZE >> 9);
-		BUG_ON(first_frame < 0);
-		BUG_ON(first_frame + num_frames > pkt->frames);
-		for (f = first_frame; f < first_frame + num_frames; f++)
-			written[f] = 1;
-	}
-	spin_unlock(&pkt->lock);
-
-	if (pkt->cache_valid) {
-		dev_dbg(ddev, "zone %llx cached\n", pkt->sector);
-		goto out_account;
-	}
-
-	/*
-	 * Schedule reads for missing parts of the packet.
-	 */
-	for (f = 0; f < pkt->frames; f++) {
-		int p, offset;
-
-		if (written[f])
-			continue;
-
-		bio = pkt->r_bios[f];
-		bio_init(bio, file_bdev(pd->bdev_file), bio->bi_inline_vecs, 1,
-			 REQ_OP_READ);
-		bio->bi_iter.bi_sector = pkt->sector + f * (CD_FRAMESIZE >> 9);
-		bio->bi_end_io = pkt_end_io_read;
-		bio->bi_private = pkt;
-
-		p = (f * CD_FRAMESIZE) / PAGE_SIZE;
-		offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
-		dev_dbg(ddev, "Adding frame %d, page:%p offs:%d\n", f,
-			pkt->pages[p], offset);
-		if (!bio_add_page(bio, pkt->pages[p], CD_FRAMESIZE, offset))
-			BUG();
-
-		atomic_inc(&pkt->io_wait);
-		pkt_queue_bio(pd, bio);
-		frames_read++;
-	}
-
-out_account:
-	dev_dbg(ddev, "need %d frames for zone %llx\n", frames_read, pkt->sector);
-	pd->stats.pkt_started++;
-	pd->stats.secs_rg += frames_read * (CD_FRAMESIZE >> 9);
-}
-
-/*
- * Find a packet matching zone, or the least recently used packet if
- * there is no match.
- */
-static struct packet_data *pkt_get_packet_data(struct pktcdvd_device *pd, int zone)
-{
-	struct packet_data *pkt;
-
-	list_for_each_entry(pkt, &pd->cdrw.pkt_free_list, list) {
-		if (pkt->sector == zone || pkt->list.next == &pd->cdrw.pkt_free_list) {
-			list_del_init(&pkt->list);
-			if (pkt->sector != zone)
-				pkt->cache_valid = 0;
-			return pkt;
-		}
-	}
-	BUG();
-	return NULL;
-}
-
-static void pkt_put_packet_data(struct pktcdvd_device *pd, struct packet_data *pkt)
-{
-	if (pkt->cache_valid) {
-		list_add(&pkt->list, &pd->cdrw.pkt_free_list);
-	} else {
-		list_add_tail(&pkt->list, &pd->cdrw.pkt_free_list);
-	}
-}
-
-static inline void pkt_set_state(struct device *ddev, struct packet_data *pkt,
-				 enum packet_data_state state)
-{
-	static const char *state_name[] = {
-		"IDLE", "WAITING", "READ_WAIT", "WRITE_WAIT", "RECOVERY", "FINISHED"
-	};
-	enum packet_data_state old_state = pkt->state;
-
-	dev_dbg(ddev, "pkt %2d : s=%6llx %s -> %s\n",
-		pkt->id, pkt->sector, state_name[old_state], state_name[state]);
-
-	pkt->state = state;
-}
-
-/*
- * Scan the work queue to see if we can start a new packet.
- * returns non-zero if any work was done.
- */
-static int pkt_handle_queue(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_data *pkt, *p;
-	struct bio *bio = NULL;
-	sector_t zone = 0; /* Suppress gcc warning */
-	struct pkt_rb_node *node, *first_node;
-	struct rb_node *n;
-
-	atomic_set(&pd->scan_queue, 0);
-
-	if (list_empty(&pd->cdrw.pkt_free_list)) {
-		dev_dbg(ddev, "no pkt\n");
-		return 0;
-	}
-
-	/*
-	 * Try to find a zone we are not already working on.
-	 */
-	spin_lock(&pd->lock);
-	first_node = pkt_rbtree_find(pd, pd->current_sector);
-	if (!first_node) {
-		n = rb_first(&pd->bio_queue);
-		if (n)
-			first_node = rb_entry(n, struct pkt_rb_node, rb_node);
-	}
-	node = first_node;
-	while (node) {
-		bio = node->bio;
-		zone = get_zone(bio->bi_iter.bi_sector, pd);
-		list_for_each_entry(p, &pd->cdrw.pkt_active_list, list) {
-			if (p->sector == zone) {
-				bio = NULL;
-				goto try_next_bio;
-			}
-		}
-		break;
-try_next_bio:
-		node = pkt_rbtree_next(node);
-		if (!node) {
-			n = rb_first(&pd->bio_queue);
-			if (n)
-				node = rb_entry(n, struct pkt_rb_node, rb_node);
-		}
-		if (node == first_node)
-			node = NULL;
-	}
-	spin_unlock(&pd->lock);
-	if (!bio) {
-		dev_dbg(ddev, "no bio\n");
-		return 0;
-	}
-
-	pkt = pkt_get_packet_data(pd, zone);
-
-	pd->current_sector = zone + pd->settings.size;
-	pkt->sector = zone;
-	BUG_ON(pkt->frames != pd->settings.size >> 2);
-	pkt->write_size = 0;
-
-	/*
-	 * Scan work queue for bios in the same zone and link them
-	 * to this packet.
-	 */
-	spin_lock(&pd->lock);
-	dev_dbg(ddev, "looking for zone %llx\n", zone);
-	while ((node = pkt_rbtree_find(pd, zone)) != NULL) {
-		sector_t tmp = get_zone(node->bio->bi_iter.bi_sector, pd);
-
-		bio = node->bio;
-		dev_dbg(ddev, "found zone=%llx\n", tmp);
-		if (tmp != zone)
-			break;
-		pkt_rbtree_erase(pd, node);
-		spin_lock(&pkt->lock);
-		bio_list_add(&pkt->orig_bios, bio);
-		pkt->write_size += bio->bi_iter.bi_size / CD_FRAMESIZE;
-		spin_unlock(&pkt->lock);
-	}
-	/* check write congestion marks, and if bio_queue_size is
-	 * below, wake up any waiters
-	 */
-	if (pd->congested &&
-	    pd->bio_queue_size <= pd->write_congestion_off) {
-		pd->congested = false;
-		wake_up_var(&pd->congested);
-	}
-	spin_unlock(&pd->lock);
-
-	pkt->sleep_time = max(PACKET_WAIT_TIME, 1);
-	pkt_set_state(ddev, pkt, PACKET_WAITING_STATE);
-	atomic_set(&pkt->run_sm, 1);
-
-	spin_lock(&pd->cdrw.active_list_lock);
-	list_add(&pkt->list, &pd->cdrw.pkt_active_list);
-	spin_unlock(&pd->cdrw.active_list_lock);
-
-	return 1;
-}
-
-/**
- * bio_list_copy_data - copy contents of data buffers from one chain of bios to
- * another
- * @src: source bio list
- * @dst: destination bio list
- *
- * Stops when it reaches the end of either the @src list or @dst list - that is,
- * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of
- * bios).
- */
-static void bio_list_copy_data(struct bio *dst, struct bio *src)
-{
-	struct bvec_iter src_iter = src->bi_iter;
-	struct bvec_iter dst_iter = dst->bi_iter;
-
-	while (1) {
-		if (!src_iter.bi_size) {
-			src = src->bi_next;
-			if (!src)
-				break;
-
-			src_iter = src->bi_iter;
-		}
-
-		if (!dst_iter.bi_size) {
-			dst = dst->bi_next;
-			if (!dst)
-				break;
-
-			dst_iter = dst->bi_iter;
-		}
-
-		bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
-	}
-}
-
-/*
- * Assemble a bio to write one packet and queue the bio for processing
- * by the underlying block device.
- */
-static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	int f;
-
-	bio_init(pkt->w_bio, file_bdev(pd->bdev_file), pkt->w_bio->bi_inline_vecs,
-		 pkt->frames, REQ_OP_WRITE);
-	pkt->w_bio->bi_iter.bi_sector = pkt->sector;
-	pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
-	pkt->w_bio->bi_private = pkt;
-
-	/* XXX: locking? */
-	for (f = 0; f < pkt->frames; f++) {
-		struct page *page = pkt->pages[(f * CD_FRAMESIZE) / PAGE_SIZE];
-		unsigned offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
-
-		if (!bio_add_page(pkt->w_bio, page, CD_FRAMESIZE, offset))
-			BUG();
-	}
-	dev_dbg(ddev, "vcnt=%d\n", pkt->w_bio->bi_vcnt);
-
-	/*
-	 * Fill-in bvec with data from orig_bios.
-	 */
-	spin_lock(&pkt->lock);
-	bio_list_copy_data(pkt->w_bio, pkt->orig_bios.head);
-
-	pkt_set_state(ddev, pkt, PACKET_WRITE_WAIT_STATE);
-	spin_unlock(&pkt->lock);
-
-	dev_dbg(ddev, "Writing %d frames for zone %llx\n", pkt->write_size, pkt->sector);
-
-	if (test_bit(PACKET_MERGE_SEGS, &pd->flags) || (pkt->write_size < pkt->frames))
-		pkt->cache_valid = 1;
-	else
-		pkt->cache_valid = 0;
-
-	/* Start the write request */
-	atomic_set(&pkt->io_wait, 1);
-	pkt_queue_bio(pd, pkt->w_bio);
-}
-
-static void pkt_finish_packet(struct packet_data *pkt, blk_status_t status)
-{
-	struct bio *bio;
-
-	if (status)
-		pkt->cache_valid = 0;
-
-	/* Finish all bios corresponding to this packet */
-	while ((bio = bio_list_pop(&pkt->orig_bios))) {
-		bio->bi_status = status;
-		bio_endio(bio);
-	}
-}
-
-static void pkt_run_state_machine(struct pktcdvd_device *pd, struct packet_data *pkt)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	dev_dbg(ddev, "pkt %d\n", pkt->id);
-
-	for (;;) {
-		switch (pkt->state) {
-		case PACKET_WAITING_STATE:
-			if ((pkt->write_size < pkt->frames) && (pkt->sleep_time > 0))
-				return;
-
-			pkt->sleep_time = 0;
-			pkt_gather_data(pd, pkt);
-			pkt_set_state(ddev, pkt, PACKET_READ_WAIT_STATE);
-			break;
-
-		case PACKET_READ_WAIT_STATE:
-			if (atomic_read(&pkt->io_wait) > 0)
-				return;
-
-			if (atomic_read(&pkt->io_errors) > 0) {
-				pkt_set_state(ddev, pkt, PACKET_RECOVERY_STATE);
-			} else {
-				pkt_start_write(pd, pkt);
-			}
-			break;
-
-		case PACKET_WRITE_WAIT_STATE:
-			if (atomic_read(&pkt->io_wait) > 0)
-				return;
-
-			if (!pkt->w_bio->bi_status) {
-				pkt_set_state(ddev, pkt, PACKET_FINISHED_STATE);
-			} else {
-				pkt_set_state(ddev, pkt, PACKET_RECOVERY_STATE);
-			}
-			break;
-
-		case PACKET_RECOVERY_STATE:
-			dev_dbg(ddev, "No recovery possible\n");
-			pkt_set_state(ddev, pkt, PACKET_FINISHED_STATE);
-			break;
-
-		case PACKET_FINISHED_STATE:
-			pkt_finish_packet(pkt, pkt->w_bio->bi_status);
-			return;
-
-		default:
-			BUG();
-			break;
-		}
-	}
-}
-
-static void pkt_handle_packets(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_data *pkt, *next;
-
-	/*
-	 * Run state machine for active packets
-	 */
-	list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-		if (atomic_read(&pkt->run_sm) > 0) {
-			atomic_set(&pkt->run_sm, 0);
-			pkt_run_state_machine(pd, pkt);
-		}
-	}
-
-	/*
-	 * Move no longer active packets to the free list
-	 */
-	spin_lock(&pd->cdrw.active_list_lock);
-	list_for_each_entry_safe(pkt, next, &pd->cdrw.pkt_active_list, list) {
-		if (pkt->state == PACKET_FINISHED_STATE) {
-			list_del(&pkt->list);
-			pkt_put_packet_data(pd, pkt);
-			pkt_set_state(ddev, pkt, PACKET_IDLE_STATE);
-			atomic_set(&pd->scan_queue, 1);
-		}
-	}
-	spin_unlock(&pd->cdrw.active_list_lock);
-}
-
-/*
- * kcdrwd is woken up when writes have been queued for one of our
- * registered devices
- */
-static int kcdrwd(void *foobar)
-{
-	struct pktcdvd_device *pd = foobar;
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_data *pkt;
-	int states[PACKET_NUM_STATES];
-	long min_sleep_time, residue;
-
-	set_user_nice(current, MIN_NICE);
-	set_freezable();
-
-	for (;;) {
-		DECLARE_WAITQUEUE(wait, current);
-
-		/*
-		 * Wait until there is something to do
-		 */
-		add_wait_queue(&pd->wqueue, &wait);
-		for (;;) {
-			set_current_state(TASK_INTERRUPTIBLE);
-
-			/* Check if we need to run pkt_handle_queue */
-			if (atomic_read(&pd->scan_queue) > 0)
-				goto work_to_do;
-
-			/* Check if we need to run the state machine for some packet */
-			list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-				if (atomic_read(&pkt->run_sm) > 0)
-					goto work_to_do;
-			}
-
-			/* Check if we need to process the iosched queues */
-			if (atomic_read(&pd->iosched.attention) != 0)
-				goto work_to_do;
-
-			/* Otherwise, go to sleep */
-			pkt_count_states(pd, states);
-			dev_dbg(ddev, "i:%d ow:%d rw:%d ww:%d rec:%d fin:%d\n",
-				states[0], states[1], states[2], states[3], states[4], states[5]);
-
-			min_sleep_time = MAX_SCHEDULE_TIMEOUT;
-			list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-				if (pkt->sleep_time && pkt->sleep_time < min_sleep_time)
-					min_sleep_time = pkt->sleep_time;
-			}
-
-			dev_dbg(ddev, "sleeping\n");
-			residue = schedule_timeout(min_sleep_time);
-			dev_dbg(ddev, "wake up\n");
-
-			/* make swsusp happy with our thread */
-			try_to_freeze();
-
-			list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-				if (!pkt->sleep_time)
-					continue;
-				pkt->sleep_time -= min_sleep_time - residue;
-				if (pkt->sleep_time <= 0) {
-					pkt->sleep_time = 0;
-					atomic_inc(&pkt->run_sm);
-				}
-			}
-
-			if (kthread_should_stop())
-				break;
-		}
-work_to_do:
-		set_current_state(TASK_RUNNING);
-		remove_wait_queue(&pd->wqueue, &wait);
-
-		if (kthread_should_stop())
-			break;
-
-		/*
-		 * if pkt_handle_queue returns true, we can queue
-		 * another request.
-		 */
-		while (pkt_handle_queue(pd))
-			;
-
-		/*
-		 * Handle packet state machine
-		 */
-		pkt_handle_packets(pd);
-
-		/*
-		 * Handle iosched queues
-		 */
-		pkt_iosched_process_queue(pd);
-	}
-
-	return 0;
-}
-
-static void pkt_print_settings(struct pktcdvd_device *pd)
-{
-	dev_info(disk_to_dev(pd->disk), "%s packets, %u blocks, Mode-%c disc\n",
-		 pd->settings.fp ? "Fixed" : "Variable",
-		 pd->settings.size >> 2,
-		 pd->settings.block_mode == 8 ? '1' : '2');
-}
-
-static int pkt_mode_sense(struct pktcdvd_device *pd, struct packet_command *cgc, int page_code, int page_control)
-{
-	memset(cgc->cmd, 0, sizeof(cgc->cmd));
-
-	cgc->cmd[0] = GPCMD_MODE_SENSE_10;
-	cgc->cmd[2] = page_code | (page_control << 6);
-	put_unaligned_be16(cgc->buflen, &cgc->cmd[7]);
-	cgc->data_direction = CGC_DATA_READ;
-	return pkt_generic_packet(pd, cgc);
-}
-
-static int pkt_mode_select(struct pktcdvd_device *pd, struct packet_command *cgc)
-{
-	memset(cgc->cmd, 0, sizeof(cgc->cmd));
-	memset(cgc->buffer, 0, 2);
-	cgc->cmd[0] = GPCMD_MODE_SELECT_10;
-	cgc->cmd[1] = 0x10;		/* PF */
-	put_unaligned_be16(cgc->buflen, &cgc->cmd[7]);
-	cgc->data_direction = CGC_DATA_WRITE;
-	return pkt_generic_packet(pd, cgc);
-}
-
-static int pkt_get_disc_info(struct pktcdvd_device *pd, disc_information *di)
-{
-	struct packet_command cgc;
-	int ret;
-
-	/* set up command and get the disc info */
-	init_cdrom_command(&cgc, di, sizeof(*di), CGC_DATA_READ);
-	cgc.cmd[0] = GPCMD_READ_DISC_INFO;
-	cgc.cmd[8] = cgc.buflen = 2;
-	cgc.quiet = 1;
-
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret)
-		return ret;
-
-	/* not all drives have the same disc_info length, so requeue
-	 * packet with the length the drive tells us it can supply
-	 */
-	cgc.buflen = be16_to_cpu(di->disc_information_length) +
-		     sizeof(di->disc_information_length);
-
-	if (cgc.buflen > sizeof(disc_information))
-		cgc.buflen = sizeof(disc_information);
-
-	cgc.cmd[8] = cgc.buflen;
-	return pkt_generic_packet(pd, &cgc);
-}
-
-static int pkt_get_track_info(struct pktcdvd_device *pd, __u16 track, __u8 type, track_information *ti)
-{
-	struct packet_command cgc;
-	int ret;
-
-	init_cdrom_command(&cgc, ti, 8, CGC_DATA_READ);
-	cgc.cmd[0] = GPCMD_READ_TRACK_RZONE_INFO;
-	cgc.cmd[1] = type & 3;
-	put_unaligned_be16(track, &cgc.cmd[4]);
-	cgc.cmd[8] = 8;
-	cgc.quiet = 1;
-
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret)
-		return ret;
-
-	cgc.buflen = be16_to_cpu(ti->track_information_length) +
-		     sizeof(ti->track_information_length);
-
-	if (cgc.buflen > sizeof(track_information))
-		cgc.buflen = sizeof(track_information);
-
-	cgc.cmd[8] = cgc.buflen;
-	return pkt_generic_packet(pd, &cgc);
-}
-
-static noinline_for_stack int pkt_get_last_written(struct pktcdvd_device *pd,
-						long *last_written)
-{
-	disc_information di;
-	track_information ti;
-	__u32 last_track;
-	int ret;
-
-	ret = pkt_get_disc_info(pd, &di);
-	if (ret)
-		return ret;
-
-	last_track = (di.last_track_msb << 8) | di.last_track_lsb;
-	ret = pkt_get_track_info(pd, last_track, 1, &ti);
-	if (ret)
-		return ret;
-
-	/* if this track is blank, try the previous. */
-	if (ti.blank) {
-		last_track--;
-		ret = pkt_get_track_info(pd, last_track, 1, &ti);
-		if (ret)
-			return ret;
-	}
-
-	/* if last recorded field is valid, return it. */
-	if (ti.lra_v) {
-		*last_written = be32_to_cpu(ti.last_rec_address);
-	} else {
-		/* make it up instead */
-		*last_written = be32_to_cpu(ti.track_start) +
-				be32_to_cpu(ti.track_size);
-		if (ti.free_blocks)
-			*last_written -= (be32_to_cpu(ti.free_blocks) + 7);
-	}
-	return 0;
-}
-
-/*
- * write mode select package based on pd->settings
- */
-static noinline_for_stack int pkt_set_write_settings(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	write_param_page *wp;
-	char buffer[128];
-	int ret, size;
-
-	/* doesn't apply to DVD+RW or DVD-RAM */
-	if ((pd->mmc3_profile == 0x1a) || (pd->mmc3_profile == 0x12))
-		return 0;
-
-	memset(buffer, 0, sizeof(buffer));
-	init_cdrom_command(&cgc, buffer, sizeof(*wp), CGC_DATA_READ);
-	cgc.sshdr = &sshdr;
-	ret = pkt_mode_sense(pd, &cgc, GPMODE_WRITE_PARMS_PAGE, 0);
-	if (ret) {
-		pkt_dump_sense(pd, &cgc);
-		return ret;
-	}
-
-	size = 2 + get_unaligned_be16(&buffer[0]);
-	pd->mode_offset = get_unaligned_be16(&buffer[6]);
-	if (size > sizeof(buffer))
-		size = sizeof(buffer);
-
-	/*
-	 * now get it all
-	 */
-	init_cdrom_command(&cgc, buffer, size, CGC_DATA_READ);
-	cgc.sshdr = &sshdr;
-	ret = pkt_mode_sense(pd, &cgc, GPMODE_WRITE_PARMS_PAGE, 0);
-	if (ret) {
-		pkt_dump_sense(pd, &cgc);
-		return ret;
-	}
-
-	/*
-	 * write page is offset header + block descriptor length
-	 */
-	wp = (write_param_page *) &buffer[sizeof(struct mode_page_header) + pd->mode_offset];
-
-	wp->fp = pd->settings.fp;
-	wp->track_mode = pd->settings.track_mode;
-	wp->write_type = pd->settings.write_type;
-	wp->data_block_type = pd->settings.block_mode;
-
-	wp->multi_session = 0;
-
-#ifdef PACKET_USE_LS
-	wp->link_size = 7;
-	wp->ls_v = 1;
-#endif
-
-	if (wp->data_block_type == PACKET_BLOCK_MODE1) {
-		wp->session_format = 0;
-		wp->subhdr2 = 0x20;
-	} else if (wp->data_block_type == PACKET_BLOCK_MODE2) {
-		wp->session_format = 0x20;
-		wp->subhdr2 = 8;
-#if 0
-		wp->mcn[0] = 0x80;
-		memcpy(&wp->mcn[1], PACKET_MCN, sizeof(wp->mcn) - 1);
-#endif
-	} else {
-		/*
-		 * paranoia
-		 */
-		dev_err(ddev, "write mode wrong %d\n", wp->data_block_type);
-		return 1;
-	}
-	wp->packet_size = cpu_to_be32(pd->settings.size >> 2);
-
-	cgc.buflen = cgc.cmd[8] = size;
-	ret = pkt_mode_select(pd, &cgc);
-	if (ret) {
-		pkt_dump_sense(pd, &cgc);
-		return ret;
-	}
-
-	pkt_print_settings(pd);
-	return 0;
-}
-
-/*
- * 1 -- we can write to this track, 0 -- we can't
- */
-static int pkt_writable_track(struct pktcdvd_device *pd, track_information *ti)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	switch (pd->mmc3_profile) {
-		case 0x1a: /* DVD+RW */
-		case 0x12: /* DVD-RAM */
-			/* The track is always writable on DVD+RW/DVD-RAM */
-			return 1;
-		default:
-			break;
-	}
-
-	if (!ti->packet || !ti->fp)
-		return 0;
-
-	/*
-	 * "good" settings as per Mt Fuji.
-	 */
-	if (ti->rt == 0 && ti->blank == 0)
-		return 1;
-
-	if (ti->rt == 0 && ti->blank == 1)
-		return 1;
-
-	if (ti->rt == 1 && ti->blank == 0)
-		return 1;
-
-	dev_err(ddev, "bad state %d-%d-%d\n", ti->rt, ti->blank, ti->packet);
-	return 0;
-}
-
-/*
- * 1 -- we can write to this disc, 0 -- we can't
- */
-static int pkt_writable_disc(struct pktcdvd_device *pd, disc_information *di)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	switch (pd->mmc3_profile) {
-		case 0x0a: /* CD-RW */
-		case 0xffff: /* MMC3 not supported */
-			break;
-		case 0x1a: /* DVD+RW */
-		case 0x13: /* DVD-RW */
-		case 0x12: /* DVD-RAM */
-			return 1;
-		default:
-			dev_dbg(ddev, "Wrong disc profile (%x)\n", pd->mmc3_profile);
-			return 0;
-	}
-
-	/*
-	 * for disc type 0xff we should probably reserve a new track.
-	 * but i'm not sure, should we leave this to user apps? probably.
-	 */
-	if (di->disc_type == 0xff) {
-		dev_notice(ddev, "unknown disc - no track?\n");
-		return 0;
-	}
-
-	if (di->disc_type != 0x20 && di->disc_type != 0) {
-		dev_err(ddev, "wrong disc type (%x)\n", di->disc_type);
-		return 0;
-	}
-
-	if (di->erasable == 0) {
-		dev_err(ddev, "disc not erasable\n");
-		return 0;
-	}
-
-	if (di->border_status == PACKET_SESSION_RESERVED) {
-		dev_err(ddev, "can't write to last track (reserved)\n");
-		return 0;
-	}
-
-	return 1;
-}
-
-static noinline_for_stack int pkt_probe_settings(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_command cgc;
-	unsigned char buf[12];
-	disc_information di;
-	track_information ti;
-	int ret, track;
-
-	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
-	cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
-	cgc.cmd[8] = 8;
-	ret = pkt_generic_packet(pd, &cgc);
-	pd->mmc3_profile = ret ? 0xffff : get_unaligned_be16(&buf[6]);
-
-	memset(&di, 0, sizeof(disc_information));
-	memset(&ti, 0, sizeof(track_information));
-
-	ret = pkt_get_disc_info(pd, &di);
-	if (ret) {
-		dev_err(ddev, "failed get_disc\n");
-		return ret;
-	}
-
-	if (!pkt_writable_disc(pd, &di))
-		return -EROFS;
-
-	pd->type = di.erasable ? PACKET_CDRW : PACKET_CDR;
-
-	track = 1; /* (di.last_track_msb << 8) | di.last_track_lsb; */
-	ret = pkt_get_track_info(pd, track, 1, &ti);
-	if (ret) {
-		dev_err(ddev, "failed get_track\n");
-		return ret;
-	}
-
-	if (!pkt_writable_track(pd, &ti)) {
-		dev_err(ddev, "can't write to this track\n");
-		return -EROFS;
-	}
-
-	/*
-	 * we keep packet size in 512 byte units, makes it easier to
-	 * deal with request calculations.
-	 */
-	pd->settings.size = be32_to_cpu(ti.fixed_packet_size) << 2;
-	if (pd->settings.size == 0) {
-		dev_notice(ddev, "detected zero packet size!\n");
-		return -ENXIO;
-	}
-	if (pd->settings.size > PACKET_MAX_SECTORS) {
-		dev_err(ddev, "packet size is too big\n");
-		return -EROFS;
-	}
-	pd->settings.fp = ti.fp;
-	pd->offset = (be32_to_cpu(ti.track_start) << 2) & (pd->settings.size - 1);
-
-	if (ti.nwa_v) {
-		pd->nwa = be32_to_cpu(ti.next_writable);
-		set_bit(PACKET_NWA_VALID, &pd->flags);
-	}
-
-	/*
-	 * in theory we could use lra on -RW media as well and just zero
-	 * blocks that haven't been written yet, but in practice that
-	 * is just a no-go. we'll use that for -R, naturally.
-	 */
-	if (ti.lra_v) {
-		pd->lra = be32_to_cpu(ti.last_rec_address);
-		set_bit(PACKET_LRA_VALID, &pd->flags);
-	} else {
-		pd->lra = 0xffffffff;
-		set_bit(PACKET_LRA_VALID, &pd->flags);
-	}
-
-	/*
-	 * fine for now
-	 */
-	pd->settings.link_loss = 7;
-	pd->settings.write_type = 0;	/* packet */
-	pd->settings.track_mode = ti.track_mode;
-
-	/*
-	 * mode1 or mode2 disc
-	 */
-	switch (ti.data_mode) {
-		case PACKET_MODE1:
-			pd->settings.block_mode = PACKET_BLOCK_MODE1;
-			break;
-		case PACKET_MODE2:
-			pd->settings.block_mode = PACKET_BLOCK_MODE2;
-			break;
-		default:
-			dev_err(ddev, "unknown data mode\n");
-			return -EROFS;
-	}
-	return 0;
-}
-
-/*
- * enable/disable write caching on drive
- */
-static noinline_for_stack int pkt_write_caching(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	unsigned char buf[64];
-	bool set = IS_ENABLED(CONFIG_CDROM_PKTCDVD_WCACHE);
-	int ret;
-
-	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
-	cgc.sshdr = &sshdr;
-	cgc.buflen = pd->mode_offset + 12;
-
-	/*
-	 * caching mode page might not be there, so quiet this command
-	 */
-	cgc.quiet = 1;
-
-	ret = pkt_mode_sense(pd, &cgc, GPMODE_WCACHING_PAGE, 0);
-	if (ret)
-		return ret;
-
-	/*
-	 * use drive write caching -- we need deferred error handling to be
-	 * able to successfully recover with this option (drive will return good
-	 * status as soon as the cdb is validated).
-	 */
-	buf[pd->mode_offset + 10] |= (set << 2);
-
-	cgc.buflen = cgc.cmd[8] = 2 + get_unaligned_be16(&buf[0]);
-	ret = pkt_mode_select(pd, &cgc);
-	if (ret) {
-		dev_err(ddev, "write caching control failed\n");
-		pkt_dump_sense(pd, &cgc);
-	} else if (!ret && set)
-		dev_notice(ddev, "enabled write caching\n");
-	return ret;
-}
-
-static int pkt_lock_door(struct pktcdvd_device *pd, int lockflag)
-{
-	struct packet_command cgc;
-
-	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
-	cgc.cmd[0] = GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL;
-	cgc.cmd[4] = lockflag ? 1 : 0;
-	return pkt_generic_packet(pd, &cgc);
-}
-
-/*
- * Returns drive maximum write speed
- */
-static noinline_for_stack int pkt_get_max_speed(struct pktcdvd_device *pd,
-						unsigned *write_speed)
-{
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	unsigned char buf[256+18];
-	unsigned char *cap_buf;
-	int ret, offset;
-
-	cap_buf = &buf[sizeof(struct mode_page_header) + pd->mode_offset];
-	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_UNKNOWN);
-	cgc.sshdr = &sshdr;
-
-	ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
-	if (ret) {
-		cgc.buflen = pd->mode_offset + cap_buf[1] + 2 +
-			     sizeof(struct mode_page_header);
-		ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
-		if (ret) {
-			pkt_dump_sense(pd, &cgc);
-			return ret;
-		}
-	}
-
-	offset = 20;			    /* Obsoleted field, used by older drives */
-	if (cap_buf[1] >= 28)
-		offset = 28;		    /* Current write speed selected */
-	if (cap_buf[1] >= 30) {
-		/* If the drive reports at least one "Logical Unit Write
-		 * Speed Performance Descriptor Block", use the information
-		 * in the first block. (contains the highest speed)
-		 */
-		int num_spdb = get_unaligned_be16(&cap_buf[30]);
-		if (num_spdb > 0)
-			offset = 34;
-	}
-
-	*write_speed = get_unaligned_be16(&cap_buf[offset]);
-	return 0;
-}
-
-/* These tables from cdrecord - I don't have orange book */
-/* standard speed CD-RW (1-4x) */
-static char clv_to_speed[16] = {
-	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
-	   0, 2, 4, 6, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-};
-/* high speed CD-RW (-10x) */
-static char hs_clv_to_speed[16] = {
-	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
-	   0, 2, 4, 6, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-};
-/* ultra high speed CD-RW */
-static char us_clv_to_speed[16] = {
-	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
-	   0, 2, 4, 8, 0, 0,16, 0,24,32,40,48, 0, 0, 0, 0
-};
-
-/*
- * reads the maximum media speed from ATIP
- */
-static noinline_for_stack int pkt_media_speed(struct pktcdvd_device *pd,
-						unsigned *speed)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	unsigned char buf[64];
-	unsigned int size, st, sp;
-	int ret;
-
-	init_cdrom_command(&cgc, buf, 2, CGC_DATA_READ);
-	cgc.sshdr = &sshdr;
-	cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
-	cgc.cmd[1] = 2;
-	cgc.cmd[2] = 4; /* READ ATIP */
-	cgc.cmd[8] = 2;
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret) {
-		pkt_dump_sense(pd, &cgc);
-		return ret;
-	}
-	size = 2 + get_unaligned_be16(&buf[0]);
-	if (size > sizeof(buf))
-		size = sizeof(buf);
-
-	init_cdrom_command(&cgc, buf, size, CGC_DATA_READ);
-	cgc.sshdr = &sshdr;
-	cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
-	cgc.cmd[1] = 2;
-	cgc.cmd[2] = 4;
-	cgc.cmd[8] = size;
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret) {
-		pkt_dump_sense(pd, &cgc);
-		return ret;
-	}
-
-	if (!(buf[6] & 0x40)) {
-		dev_notice(ddev, "disc type is not CD-RW\n");
-		return 1;
-	}
-	if (!(buf[6] & 0x4)) {
-		dev_notice(ddev, "A1 values on media are not valid, maybe not CDRW?\n");
-		return 1;
-	}
-
-	st = (buf[6] >> 3) & 0x7; /* disc sub-type */
-
-	sp = buf[16] & 0xf; /* max speed from ATIP A1 field */
-
-	/* Info from cdrecord */
-	switch (st) {
-		case 0: /* standard speed */
-			*speed = clv_to_speed[sp];
-			break;
-		case 1: /* high speed */
-			*speed = hs_clv_to_speed[sp];
-			break;
-		case 2: /* ultra high speed */
-			*speed = us_clv_to_speed[sp];
-			break;
-		default:
-			dev_notice(ddev, "unknown disc sub-type %d\n", st);
-			return 1;
-	}
-	if (*speed) {
-		dev_info(ddev, "maximum media speed: %d\n", *speed);
-		return 0;
-	} else {
-		dev_notice(ddev, "unknown speed %d for sub-type %d\n", sp, st);
-		return 1;
-	}
-}
-
-static noinline_for_stack int pkt_perform_opc(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct packet_command cgc;
-	struct scsi_sense_hdr sshdr;
-	int ret;
-
-	dev_dbg(ddev, "Performing OPC\n");
-
-	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
-	cgc.sshdr = &sshdr;
-	cgc.timeout = 60*HZ;
-	cgc.cmd[0] = GPCMD_SEND_OPC;
-	cgc.cmd[1] = 1;
-	ret = pkt_generic_packet(pd, &cgc);
-	if (ret)
-		pkt_dump_sense(pd, &cgc);
-	return ret;
-}
-
-static int pkt_open_write(struct pktcdvd_device *pd)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	int ret;
-	unsigned int write_speed, media_write_speed, read_speed;
-
-	ret = pkt_probe_settings(pd);
-	if (ret) {
-		dev_dbg(ddev, "failed probe\n");
-		return ret;
-	}
-
-	ret = pkt_set_write_settings(pd);
-	if (ret) {
-		dev_notice(ddev, "failed saving write settings\n");
-		return -EIO;
-	}
-
-	pkt_write_caching(pd);
-
-	ret = pkt_get_max_speed(pd, &write_speed);
-	if (ret)
-		write_speed = 16 * 177;
-	switch (pd->mmc3_profile) {
-		case 0x13: /* DVD-RW */
-		case 0x1a: /* DVD+RW */
-		case 0x12: /* DVD-RAM */
-			dev_notice(ddev, "write speed %ukB/s\n", write_speed);
-			break;
-		default:
-			ret = pkt_media_speed(pd, &media_write_speed);
-			if (ret)
-				media_write_speed = 16;
-			write_speed = min(write_speed, media_write_speed * 177);
-			dev_notice(ddev, "write speed %ux\n", write_speed / 176);
-			break;
-	}
-	read_speed = write_speed;
-
-	ret = pkt_set_speed(pd, write_speed, read_speed);
-	if (ret) {
-		dev_notice(ddev, "couldn't set write speed\n");
-		return -EIO;
-	}
-	pd->write_speed = write_speed;
-	pd->read_speed = read_speed;
-
-	ret = pkt_perform_opc(pd);
-	if (ret)
-		dev_notice(ddev, "Optimum Power Calibration failed\n");
-
-	return 0;
-}
-
-/*
- * called at open time.
- */
-static int pkt_open_dev(struct pktcdvd_device *pd, bool write)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	int ret;
-	long lba;
-	struct request_queue *q;
-	struct file *bdev_file;
-
-	/*
-	 * We need to re-open the cdrom device without O_NONBLOCK to be able
-	 * to read/write from/to it. It is already opened in O_NONBLOCK mode
-	 * so open should not fail.
-	 */
-	bdev_file = bdev_file_open_by_dev(file_bdev(pd->bdev_file)->bd_dev,
-				       BLK_OPEN_READ, pd, NULL);
-	if (IS_ERR(bdev_file)) {
-		ret = PTR_ERR(bdev_file);
-		goto out;
-	}
-	pd->f_open_bdev = bdev_file;
-
-	ret = pkt_get_last_written(pd, &lba);
-	if (ret) {
-		dev_err(ddev, "pkt_get_last_written failed\n");
-		goto out_putdev;
-	}
-
-	set_capacity(pd->disk, lba << 2);
-	set_capacity_and_notify(file_bdev(pd->bdev_file)->bd_disk, lba << 2);
-
-	q = bdev_get_queue(file_bdev(pd->bdev_file));
-	if (write) {
-		ret = pkt_open_write(pd);
-		if (ret)
-			goto out_putdev;
-		set_bit(PACKET_WRITABLE, &pd->flags);
-	} else {
-		pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
-		clear_bit(PACKET_WRITABLE, &pd->flags);
-	}
-
-	ret = pkt_set_segment_merging(pd, q);
-	if (ret)
-		goto out_putdev;
-
-	if (write) {
-		if (!pkt_grow_pktlist(pd, CONFIG_CDROM_PKTCDVD_BUFFERS)) {
-			dev_err(ddev, "not enough memory for buffers\n");
-			ret = -ENOMEM;
-			goto out_putdev;
-		}
-		dev_info(ddev, "%lukB available on disc\n", lba << 1);
-	}
-	set_blocksize(bdev_file, CD_FRAMESIZE);
-
-	return 0;
-
-out_putdev:
-	fput(bdev_file);
-out:
-	return ret;
-}
-
-/*
- * called when the device is closed. makes sure that the device flushes
- * the internal cache before we close.
- */
-static void pkt_release_dev(struct pktcdvd_device *pd, int flush)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-
-	if (flush && pkt_flush_cache(pd))
-		dev_notice(ddev, "not flushing cache\n");
-
-	pkt_lock_door(pd, 0);
-
-	pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
-	fput(pd->f_open_bdev);
-	pd->f_open_bdev = NULL;
-
-	pkt_shrink_pktlist(pd);
-}
-
-static struct pktcdvd_device *pkt_find_dev_from_minor(unsigned int dev_minor)
-{
-	if (dev_minor >= MAX_WRITERS)
-		return NULL;
-
-	dev_minor = array_index_nospec(dev_minor, MAX_WRITERS);
-	return pkt_devs[dev_minor];
-}
-
-static int pkt_open(struct gendisk *disk, blk_mode_t mode)
-{
-	struct pktcdvd_device *pd = NULL;
-	int ret;
-
-	mutex_lock(&pktcdvd_mutex);
-	mutex_lock(&ctl_mutex);
-	pd = pkt_find_dev_from_minor(disk->first_minor);
-	if (!pd) {
-		ret = -ENODEV;
-		goto out;
-	}
-	BUG_ON(pd->refcnt < 0);
-
-	pd->refcnt++;
-	if (pd->refcnt > 1) {
-		if ((mode & BLK_OPEN_WRITE) &&
-		    !test_bit(PACKET_WRITABLE, &pd->flags)) {
-			ret = -EBUSY;
-			goto out_dec;
-		}
-	} else {
-		ret = pkt_open_dev(pd, mode & BLK_OPEN_WRITE);
-		if (ret)
-			goto out_dec;
-	}
-	mutex_unlock(&ctl_mutex);
-	mutex_unlock(&pktcdvd_mutex);
-	return 0;
-
-out_dec:
-	pd->refcnt--;
-out:
-	mutex_unlock(&ctl_mutex);
-	mutex_unlock(&pktcdvd_mutex);
-	return ret;
-}
-
-static void pkt_release(struct gendisk *disk)
-{
-	struct pktcdvd_device *pd = disk->private_data;
-
-	mutex_lock(&pktcdvd_mutex);
-	mutex_lock(&ctl_mutex);
-	pd->refcnt--;
-	BUG_ON(pd->refcnt < 0);
-	if (pd->refcnt == 0) {
-		int flush = test_bit(PACKET_WRITABLE, &pd->flags);
-		pkt_release_dev(pd, flush);
-	}
-	mutex_unlock(&ctl_mutex);
-	mutex_unlock(&pktcdvd_mutex);
-}
-
-
-static void pkt_end_io_read_cloned(struct bio *bio)
-{
-	struct packet_stacked_data *psd = bio->bi_private;
-	struct pktcdvd_device *pd = psd->pd;
-
-	psd->bio->bi_status = bio->bi_status;
-	bio_put(bio);
-	bio_endio(psd->bio);
-	mempool_free(psd, &psd_pool);
-	pkt_bio_finished(pd);
-}
-
-static void pkt_make_request_read(struct pktcdvd_device *pd, struct bio *bio)
-{
-	struct bio *cloned_bio = bio_alloc_clone(file_bdev(pd->bdev_file), bio,
-		GFP_NOIO, &pkt_bio_set);
-	struct packet_stacked_data *psd = mempool_alloc(&psd_pool, GFP_NOIO);
-
-	psd->pd = pd;
-	psd->bio = bio;
-	cloned_bio->bi_private = psd;
-	cloned_bio->bi_end_io = pkt_end_io_read_cloned;
-	pd->stats.secs_r += bio_sectors(bio);
-	pkt_queue_bio(pd, cloned_bio);
-}
-
-static void pkt_make_request_write(struct bio *bio)
-{
-	struct pktcdvd_device *pd = bio->bi_bdev->bd_disk->private_data;
-	sector_t zone;
-	struct packet_data *pkt;
-	int was_empty, blocked_bio;
-	struct pkt_rb_node *node;
-
-	zone = get_zone(bio->bi_iter.bi_sector, pd);
-
-	/*
-	 * If we find a matching packet in state WAITING or READ_WAIT, we can
-	 * just append this bio to that packet.
-	 */
-	spin_lock(&pd->cdrw.active_list_lock);
-	blocked_bio = 0;
-	list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
-		if (pkt->sector == zone) {
-			spin_lock(&pkt->lock);
-			if ((pkt->state == PACKET_WAITING_STATE) ||
-			    (pkt->state == PACKET_READ_WAIT_STATE)) {
-				bio_list_add(&pkt->orig_bios, bio);
-				pkt->write_size +=
-					bio->bi_iter.bi_size / CD_FRAMESIZE;
-				if ((pkt->write_size >= pkt->frames) &&
-				    (pkt->state == PACKET_WAITING_STATE)) {
-					atomic_inc(&pkt->run_sm);
-					wake_up(&pd->wqueue);
-				}
-				spin_unlock(&pkt->lock);
-				spin_unlock(&pd->cdrw.active_list_lock);
-				return;
-			} else {
-				blocked_bio = 1;
-			}
-			spin_unlock(&pkt->lock);
-		}
-	}
-	spin_unlock(&pd->cdrw.active_list_lock);
-
-	/*
-	 * Test if there is enough room left in the bio work queue
-	 * (queue size >= congestion on mark).
-	 * If not, wait till the work queue size is below the congestion off mark.
-	 */
-	spin_lock(&pd->lock);
-	if (pd->write_congestion_on > 0
-	    && pd->bio_queue_size >= pd->write_congestion_on) {
-		struct wait_bit_queue_entry wqe;
-
-		init_wait_var_entry(&wqe, &pd->congested, 0);
-		for (;;) {
-			prepare_to_wait_event(__var_waitqueue(&pd->congested),
-					      &wqe.wq_entry,
-					      TASK_UNINTERRUPTIBLE);
-			if (pd->bio_queue_size <= pd->write_congestion_off)
-				break;
-			pd->congested = true;
-			spin_unlock(&pd->lock);
-			schedule();
-			spin_lock(&pd->lock);
-		}
-	}
-	spin_unlock(&pd->lock);
-
-	/*
-	 * No matching packet found. Store the bio in the work queue.
-	 */
-	node = mempool_alloc(&pd->rb_pool, GFP_NOIO);
-	node->bio = bio;
-	spin_lock(&pd->lock);
-	BUG_ON(pd->bio_queue_size < 0);
-	was_empty = (pd->bio_queue_size == 0);
-	pkt_rbtree_insert(pd, node);
-	spin_unlock(&pd->lock);
-
-	/*
-	 * Wake up the worker thread.
-	 */
-	atomic_set(&pd->scan_queue, 1);
-	if (was_empty) {
-		/* This wake_up is required for correct operation */
-		wake_up(&pd->wqueue);
-	} else if (!list_empty(&pd->cdrw.pkt_free_list) && !blocked_bio) {
-		/*
-		 * This wake up is not required for correct operation,
-		 * but improves performance in some cases.
-		 */
-		wake_up(&pd->wqueue);
-	}
-}
-
-static void pkt_submit_bio(struct bio *bio)
-{
-	struct pktcdvd_device *pd = bio->bi_bdev->bd_disk->private_data;
-	struct device *ddev = disk_to_dev(pd->disk);
-	struct bio *split;
-
-	bio = bio_split_to_limits(bio);
-	if (!bio)
-		return;
-
-	dev_dbg(ddev, "start = %6llx stop = %6llx\n",
-		bio->bi_iter.bi_sector, bio_end_sector(bio));
-
-	/*
-	 * Clone READ bios so we can have our own bi_end_io callback.
-	 */
-	if (bio_data_dir(bio) == READ) {
-		pkt_make_request_read(pd, bio);
-		return;
-	}
-
-	if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
-		dev_notice(ddev, "WRITE for ro device (%llu)\n", bio->bi_iter.bi_sector);
-		goto end_io;
-	}
-
-	if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
-		dev_err(ddev, "wrong bio size\n");
-		goto end_io;
-	}
-
-	do {
-		sector_t zone = get_zone(bio->bi_iter.bi_sector, pd);
-		sector_t last_zone = get_zone(bio_end_sector(bio) - 1, pd);
-
-		if (last_zone != zone) {
-			BUG_ON(last_zone != zone + pd->settings.size);
-
-			split = bio_split(bio, last_zone -
-					  bio->bi_iter.bi_sector,
-					  GFP_NOIO, &pkt_bio_set);
-			bio_chain(split, bio);
-		} else {
-			split = bio;
-		}
-
-		pkt_make_request_write(split);
-	} while (split != bio);
-
-	return;
-end_io:
-	bio_io_error(bio);
-}
-
-static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
-{
-	struct device *ddev = disk_to_dev(pd->disk);
-	int i;
-	struct file *bdev_file;
-	struct scsi_device *sdev;
-
-	if (pd->pkt_dev == dev) {
-		dev_err(ddev, "recursive setup not allowed\n");
-		return -EBUSY;
-	}
-	for (i = 0; i < MAX_WRITERS; i++) {
-		struct pktcdvd_device *pd2 = pkt_devs[i];
-		if (!pd2)
-			continue;
-		if (file_bdev(pd2->bdev_file)->bd_dev == dev) {
-			dev_err(ddev, "%pg already setup\n",
-				file_bdev(pd2->bdev_file));
-			return -EBUSY;
-		}
-		if (pd2->pkt_dev == dev) {
-			dev_err(ddev, "can't chain pktcdvd devices\n");
-			return -EBUSY;
-		}
-	}
-
-	bdev_file = bdev_file_open_by_dev(dev, BLK_OPEN_READ | BLK_OPEN_NDELAY,
-				       NULL, NULL);
-	if (IS_ERR(bdev_file))
-		return PTR_ERR(bdev_file);
-	sdev = scsi_device_from_queue(file_bdev(bdev_file)->bd_disk->queue);
-	if (!sdev) {
-		fput(bdev_file);
-		return -EINVAL;
-	}
-	put_device(&sdev->sdev_gendev);
-
-	/* This is safe, since we have a reference from open(). */
-	__module_get(THIS_MODULE);
-
-	pd->bdev_file = bdev_file;
-
-	atomic_set(&pd->cdrw.pending_bios, 0);
-	pd->cdrw.thread = kthread_run(kcdrwd, pd, "%s", pd->disk->disk_name);
-	if (IS_ERR(pd->cdrw.thread)) {
-		dev_err(ddev, "can't start kernel thread\n");
-		goto out_mem;
-	}
-
-	proc_create_single_data(pd->disk->disk_name, 0, pkt_proc, pkt_seq_show, pd);
-	dev_notice(ddev, "writer mapped to %pg\n", file_bdev(bdev_file));
-	return 0;
-
-out_mem:
-	fput(bdev_file);
-	/* This is safe: open() is still holding a reference. */
-	module_put(THIS_MODULE);
-	return -ENOMEM;
-}
-
-static int pkt_ioctl(struct block_device *bdev, blk_mode_t mode,
-		unsigned int cmd, unsigned long arg)
-{
-	struct pktcdvd_device *pd = bdev->bd_disk->private_data;
-	struct device *ddev = disk_to_dev(pd->disk);
-	int ret;
-
-	dev_dbg(ddev, "cmd %x, dev %d:%d\n", cmd, MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev));
-
-	mutex_lock(&pktcdvd_mutex);
-	switch (cmd) {
-	case CDROMEJECT:
-		/*
-		 * The door gets locked when the device is opened, so we
-		 * have to unlock it or else the eject command fails.
-		 */
-		if (pd->refcnt == 1)
-			pkt_lock_door(pd, 0);
-		fallthrough;
-	/*
-	 * forward selected CDROM ioctls to CD-ROM, for UDF
-	 */
-	case CDROMMULTISESSION:
-	case CDROMREADTOCENTRY:
-	case CDROM_LAST_WRITTEN:
-	case CDROM_SEND_PACKET:
-	case SCSI_IOCTL_SEND_COMMAND:
-		if (!bdev->bd_disk->fops->ioctl)
-			ret = -ENOTTY;
-		else
-			ret = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
-		break;
-	default:
-		dev_dbg(ddev, "Unknown ioctl (%x)\n", cmd);
-		ret = -ENOTTY;
-	}
-	mutex_unlock(&pktcdvd_mutex);
-
-	return ret;
-}
-
-static unsigned int pkt_check_events(struct gendisk *disk,
-				     unsigned int clearing)
-{
-	struct pktcdvd_device *pd = disk->private_data;
-	struct gendisk *attached_disk;
-
-	if (!pd)
-		return 0;
-	if (!pd->bdev_file)
-		return 0;
-	attached_disk = file_bdev(pd->bdev_file)->bd_disk;
-	if (!attached_disk || !attached_disk->fops->check_events)
-		return 0;
-	return attached_disk->fops->check_events(attached_disk, clearing);
-}
-
-static char *pkt_devnode(struct gendisk *disk, umode_t *mode)
-{
-	return kasprintf(GFP_KERNEL, "pktcdvd/%s", disk->disk_name);
-}
-
-static const struct block_device_operations pktcdvd_ops = {
-	.owner =		THIS_MODULE,
-	.submit_bio =		pkt_submit_bio,
-	.open =			pkt_open,
-	.release =		pkt_release,
-	.ioctl =		pkt_ioctl,
-	.compat_ioctl =		blkdev_compat_ptr_ioctl,
-	.check_events =		pkt_check_events,
-	.devnode =		pkt_devnode,
-};
-
-/*
- * Set up mapping from pktcdvd device to CD-ROM device.
- */
-static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
-{
-	struct queue_limits lim = {
-		.max_hw_sectors		= PACKET_MAX_SECTORS,
-		.logical_block_size	= CD_FRAMESIZE,
-		.features		= BLK_FEAT_ROTATIONAL,
-	};
-	int idx;
-	int ret = -ENOMEM;
-	struct pktcdvd_device *pd;
-	struct gendisk *disk;
-
-	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
-
-	for (idx = 0; idx < MAX_WRITERS; idx++)
-		if (!pkt_devs[idx])
-			break;
-	if (idx == MAX_WRITERS) {
-		pr_err("max %d writers supported\n", MAX_WRITERS);
-		ret = -EBUSY;
-		goto out_mutex;
-	}
-
-	pd = kzalloc(sizeof(struct pktcdvd_device), GFP_KERNEL);
-	if (!pd)
-		goto out_mutex;
-
-	ret = mempool_init_kmalloc_pool(&pd->rb_pool, PKT_RB_POOL_SIZE,
-					sizeof(struct pkt_rb_node));
-	if (ret)
-		goto out_mem;
-
-	INIT_LIST_HEAD(&pd->cdrw.pkt_free_list);
-	INIT_LIST_HEAD(&pd->cdrw.pkt_active_list);
-	spin_lock_init(&pd->cdrw.active_list_lock);
-
-	spin_lock_init(&pd->lock);
-	spin_lock_init(&pd->iosched.lock);
-	bio_list_init(&pd->iosched.read_queue);
-	bio_list_init(&pd->iosched.write_queue);
-	init_waitqueue_head(&pd->wqueue);
-	pd->bio_queue = RB_ROOT;
-
-	pd->write_congestion_on  = write_congestion_on;
-	pd->write_congestion_off = write_congestion_off;
-
-	disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
-	if (IS_ERR(disk)) {
-		ret = PTR_ERR(disk);
-		goto out_mem;
-	}
-	pd->disk = disk;
-	disk->major = pktdev_major;
-	disk->first_minor = idx;
-	disk->minors = 1;
-	disk->fops = &pktcdvd_ops;
-	disk->flags = GENHD_FL_REMOVABLE | GENHD_FL_NO_PART;
-	snprintf(disk->disk_name, sizeof(disk->disk_name), DRIVER_NAME"%d", idx);
-	disk->private_data = pd;
-
-	pd->pkt_dev = MKDEV(pktdev_major, idx);
-	ret = pkt_new_dev(pd, dev);
-	if (ret)
-		goto out_mem2;
-
-	/* inherit events of the host device */
-	disk->events = file_bdev(pd->bdev_file)->bd_disk->events;
-
-	ret = add_disk(disk);
-	if (ret)
-		goto out_mem2;
-
-	pkt_sysfs_dev_new(pd);
-	pkt_debugfs_dev_new(pd);
-
-	pkt_devs[idx] = pd;
-	if (pkt_dev)
-		*pkt_dev = pd->pkt_dev;
-
-	mutex_unlock(&ctl_mutex);
-	return 0;
-
-out_mem2:
-	put_disk(disk);
-out_mem:
-	mempool_exit(&pd->rb_pool);
-	kfree(pd);
-out_mutex:
-	mutex_unlock(&ctl_mutex);
-	pr_err("setup of pktcdvd device failed\n");
-	return ret;
-}
-
-/*
- * Tear down mapping from pktcdvd device to CD-ROM device.
- */
-static int pkt_remove_dev(dev_t pkt_dev)
-{
-	struct pktcdvd_device *pd;
-	struct device *ddev;
-	int idx;
-	int ret = 0;
-
-	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
-
-	for (idx = 0; idx < MAX_WRITERS; idx++) {
-		pd = pkt_devs[idx];
-		if (pd && (pd->pkt_dev == pkt_dev))
-			break;
-	}
-	if (idx == MAX_WRITERS) {
-		pr_debug("dev not setup\n");
-		ret = -ENXIO;
-		goto out;
-	}
-
-	if (pd->refcnt > 0) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	ddev = disk_to_dev(pd->disk);
-
-	if (!IS_ERR(pd->cdrw.thread))
-		kthread_stop(pd->cdrw.thread);
-
-	pkt_devs[idx] = NULL;
-
-	pkt_debugfs_dev_remove(pd);
-	pkt_sysfs_dev_remove(pd);
-
-	fput(pd->bdev_file);
-
-	remove_proc_entry(pd->disk->disk_name, pkt_proc);
-	dev_notice(ddev, "writer unmapped\n");
-
-	del_gendisk(pd->disk);
-	put_disk(pd->disk);
-
-	mempool_exit(&pd->rb_pool);
-	kfree(pd);
-
-	/* This is safe: open() is still holding a reference. */
-	module_put(THIS_MODULE);
-
-out:
-	mutex_unlock(&ctl_mutex);
-	return ret;
-}
-
-static void pkt_get_status(struct pkt_ctrl_command *ctrl_cmd)
-{
-	struct pktcdvd_device *pd;
-
-	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
-
-	pd = pkt_find_dev_from_minor(ctrl_cmd->dev_index);
-	if (pd) {
-		ctrl_cmd->dev = new_encode_dev(file_bdev(pd->bdev_file)->bd_dev);
-		ctrl_cmd->pkt_dev = new_encode_dev(pd->pkt_dev);
-	} else {
-		ctrl_cmd->dev = 0;
-		ctrl_cmd->pkt_dev = 0;
-	}
-	ctrl_cmd->num_devices = MAX_WRITERS;
-
-	mutex_unlock(&ctl_mutex);
-}
-
-static long pkt_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	void __user *argp = (void __user *)arg;
-	struct pkt_ctrl_command ctrl_cmd;
-	int ret = 0;
-	dev_t pkt_dev = 0;
-
-	if (cmd != PACKET_CTRL_CMD)
-		return -ENOTTY;
-
-	if (copy_from_user(&ctrl_cmd, argp, sizeof(struct pkt_ctrl_command)))
-		return -EFAULT;
-
-	switch (ctrl_cmd.command) {
-	case PKT_CTRL_CMD_SETUP:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-		ret = pkt_setup_dev(new_decode_dev(ctrl_cmd.dev), &pkt_dev);
-		ctrl_cmd.pkt_dev = new_encode_dev(pkt_dev);
-		break;
-	case PKT_CTRL_CMD_TEARDOWN:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-		ret = pkt_remove_dev(new_decode_dev(ctrl_cmd.pkt_dev));
-		break;
-	case PKT_CTRL_CMD_STATUS:
-		pkt_get_status(&ctrl_cmd);
-		break;
-	default:
-		return -ENOTTY;
-	}
-
-	if (copy_to_user(argp, &ctrl_cmd, sizeof(struct pkt_ctrl_command)))
-		return -EFAULT;
-	return ret;
-}
-
-#ifdef CONFIG_COMPAT
-static long pkt_ctl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	return pkt_ctl_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
-}
-#endif
-
-static const struct file_operations pkt_ctl_fops = {
-	.open		= nonseekable_open,
-	.unlocked_ioctl	= pkt_ctl_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl	= pkt_ctl_compat_ioctl,
-#endif
-	.owner		= THIS_MODULE,
-};
-
-static struct miscdevice pkt_misc = {
-	.minor 		= MISC_DYNAMIC_MINOR,
-	.name  		= DRIVER_NAME,
-	.nodename	= "pktcdvd/control",
-	.fops  		= &pkt_ctl_fops
-};
-
-static int __init pkt_init(void)
-{
-	int ret;
-
-	mutex_init(&ctl_mutex);
-
-	ret = mempool_init_kmalloc_pool(&psd_pool, PSD_POOL_SIZE,
-				    sizeof(struct packet_stacked_data));
-	if (ret)
-		return ret;
-	ret = bioset_init(&pkt_bio_set, BIO_POOL_SIZE, 0, 0);
-	if (ret) {
-		mempool_exit(&psd_pool);
-		return ret;
-	}
-
-	ret = register_blkdev(pktdev_major, DRIVER_NAME);
-	if (ret < 0) {
-		pr_err("unable to register block device\n");
-		goto out2;
-	}
-	if (!pktdev_major)
-		pktdev_major = ret;
-
-	ret = pkt_sysfs_init();
-	if (ret)
-		goto out;
-
-	pkt_debugfs_init();
-
-	ret = misc_register(&pkt_misc);
-	if (ret) {
-		pr_err("unable to register misc device\n");
-		goto out_misc;
-	}
-
-	pkt_proc = proc_mkdir("driver/"DRIVER_NAME, NULL);
-
-	return 0;
-
-out_misc:
-	pkt_debugfs_cleanup();
-	pkt_sysfs_cleanup();
-out:
-	unregister_blkdev(pktdev_major, DRIVER_NAME);
-out2:
-	mempool_exit(&psd_pool);
-	bioset_exit(&pkt_bio_set);
-	return ret;
-}
-
-static void __exit pkt_exit(void)
-{
-	remove_proc_entry("driver/"DRIVER_NAME, NULL);
-	misc_deregister(&pkt_misc);
-
-	pkt_debugfs_cleanup();
-	pkt_sysfs_cleanup();
-
-	unregister_blkdev(pktdev_major, DRIVER_NAME);
-	mempool_exit(&psd_pool);
-	bioset_exit(&pkt_bio_set);
-}
-
-MODULE_DESCRIPTION("Packet writing layer for CD/DVD drives");
-MODULE_AUTHOR("Jens Axboe <[e-mail]>");
-MODULE_LICENSE("GPL");
-
-module_init(pkt_init);
-module_exit(pkt_exit);

include/linux/pktcdvd.h

···
-/*
- * Copyright (C) 2000 Jens Axboe <[e-mail]>
- * Copyright (C) 2001-2004 Peter Osterlund <[e-mail]>
- *
- * May be copied or modified under the terms of the GNU General Public
- * License.  See linux/COPYING for more information.
- *
- * Packet writing layer for ATAPI and SCSI CD-R, CD-RW, DVD-R, and
- * DVD-RW devices.
- *
- */
-#ifndef __PKTCDVD_H
-#define __PKTCDVD_H
-
-#include <linux/blkdev.h>
-#include <linux/completion.h>
-#include <linux/cdrom.h>
-#include <linux/kobject.h>
-#include <linux/sysfs.h>
-#include <linux/mempool.h>
-#include <uapi/linux/pktcdvd.h>
-
-/* default bio write queue congestion marks */
-#define PKT_WRITE_CONGESTION_ON    10000
-#define PKT_WRITE_CONGESTION_OFF   9000
-
-
-struct packet_settings
-{
-	__u32			size;		/* packet size in (512 byte) sectors */
-	__u8			fp;		/* fixed packets */
-	__u8			link_loss;	/* the rest is specified
-						 * as per Mt Fuji */
-	__u8			write_type;
-	__u8			track_mode;
-	__u8			block_mode;
-};
-
-/*
- * Very crude stats for now
- */
-struct packet_stats
-{
-	unsigned long		pkt_started;
-	unsigned long		pkt_ended;
-	unsigned long		secs_w;
-	unsigned long		secs_rg;
-	unsigned long		secs_r;
-};
-
-struct packet_cdrw
-{
-	struct list_head	pkt_free_list;
-	struct list_head	pkt_active_list;
-	spinlock_t		active_list_lock; /* Serialize access to pkt_active_list */
-	struct task_struct	*thread;
-	atomic_t		pending_bios;
-};
-
-/*
- * Switch to high speed reading after reading this many kilobytes
- * with no interspersed writes.
- */
-#define HI_SPEED_SWITCH 512
-
-struct packet_iosched
-{
-	atomic_t		attention;	/* Set to non-zero when queue processing is needed */
-	int			writing;	/* Non-zero when writing, zero when reading */
-	spinlock_t		lock;		/* Protecting read/write queue manipulations */
-	struct bio_list		read_queue;
-	struct bio_list		write_queue;
-	sector_t		last_write;	/* The sector where the last write ended */
-	int			successive_reads;
-};
-
-/*
- * 32 buffers of 2048 bytes
- */
-#if (PAGE_SIZE % CD_FRAMESIZE) != 0
-#error "PAGE_SIZE must be a multiple of CD_FRAMESIZE"
-#endif
-#define PACKET_MAX_SIZE		128
-#define FRAMES_PER_PAGE		(PAGE_SIZE / CD_FRAMESIZE)
-#define PACKET_MAX_SECTORS	(PACKET_MAX_SIZE * CD_FRAMESIZE >> 9)
-
-enum packet_data_state {
-	PACKET_IDLE_STATE,			/* Not used at the moment */
-	PACKET_WAITING_STATE,			/* Waiting for more bios to arrive, so */
-						/* we don't have to do as much */
-						/* data gathering */
-	PACKET_READ_WAIT_STATE,			/* Waiting for reads to fill in holes */
-	PACKET_WRITE_WAIT_STATE,		/* Waiting for the write to complete */
-	PACKET_RECOVERY_STATE,			/* Recover after read/write errors */
-	PACKET_FINISHED_STATE,			/* After write has finished */
-
-	PACKET_NUM_STATES			/* Number of possible states */
-};
-
-/*
- * Information needed for writing a single packet
- */
-struct pktcdvd_device;
-
-struct packet_data
-{
-	struct list_head	list;
-
-	spinlock_t		lock;		/* Lock protecting state transitions and */
-						/* orig_bios list */
-
-	struct bio_list		orig_bios;	/* Original bios passed to pkt_make_request */
-						/* that will be handled by this packet */
-	int			write_size;	/* Total size of all bios in the orig_bios */
-						/* list, measured in number of frames */
-
-	struct bio		*w_bio;		/* The bio we will send to the real CD */
-						/* device once we have all data for the */
-						/* packet we are going to write */
-	sector_t		sector;		/* First sector in this packet */
-	int			frames;		/* Number of frames in this packet */
-
-	enum packet_data_state	state;		/* Current state */
-	atomic_t		run_sm;		/* Incremented whenever the state */
-						/* machine needs to be run */
-	long			sleep_time;	/* Set this to non-zero to make the state */
-						/* machine run after this many jiffies. */
-
-	atomic_t		io_wait;	/* Number of pending IO operations */
-	atomic_t		io_errors;	/* Number of read/write errors during IO */
-
-	struct bio		*r_bios[PACKET_MAX_SIZE]; /* bios to use during data gathering */
-	struct page		*pages[PACKET_MAX_SIZE / FRAMES_PER_PAGE];
-
-	int			cache_valid;	/* If non-zero, the data for the zone defined */
-						/* by the sector variable is completely cached */
-						/* in the pages[] vector. */
-
-	int			id;		/* ID number for debugging */
-	struct pktcdvd_device	*pd;
-};
-
-struct pkt_rb_node {
-	struct rb_node		rb_node;
-	struct bio		*bio;
-};
-
-struct packet_stacked_data
-{
-	struct bio		*bio;		/* Original read request bio */
-	struct pktcdvd_device	*pd;
-};
-#define PSD_POOL_SIZE		64
-
-struct pktcdvd_device
-{
-	struct file		*bdev_file;	/* dev attached */
-	/* handle acquired for bdev during pkt_open_dev() */
-	struct file		*f_open_bdev;
-	dev_t			pkt_dev;	/* our dev */
-	struct packet_settings	settings;
-	struct packet_stats	stats;
-	int			refcnt;		/* Open count */
-	int			write_speed;	/* current write speed, kB/s */
-	int			read_speed;	/* current read speed, kB/s */
-	unsigned long		offset;		/* start offset */
-	__u8			mode_offset;	/* 0 / 8 */
-	__u8			type;
-	unsigned long		flags;
-	__u16			mmc3_profile;
-	__u32			nwa;		/* next writable address */
-	__u32			lra;		/* last recorded address */
-	struct packet_cdrw	cdrw;
-	wait_queue_head_t	wqueue;
-
-	spinlock_t		lock;		/* Serialize access to bio_queue */
-	struct rb_root		bio_queue;	/* Work queue of bios we need to handle */
-	int			bio_queue_size;	/* Number of nodes in bio_queue */
-	bool			congested;	/* Someone is waiting for bio_queue_size
-						 * to drop. */
-	sector_t		current_sector;	/* Keep track of where the elevator is */
-	atomic_t		scan_queue;	/* Set to non-zero when pkt_handle_queue */
-						/* needs to be run. */
-	mempool_t		rb_pool;	/* mempool for pkt_rb_node allocations */
-
-	struct packet_iosched   iosched;
-	struct gendisk		*disk;
-
-	int			write_congestion_off;
-	int			write_congestion_on;
-
-	struct device		*dev;		/* sysfs pktcdvd[0-7] dev */
-
-	struct dentry		*dfs_d_root;	/* debugfs: devname directory */
-	struct dentry		*dfs_f_info;	/* debugfs: info file */
-};
-
-#endif /* __PKTCDVD_H */