Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1242 insertions, 0 deletions

diff --git a/Documentation/userspace-api/ioctl/cdrom.rst b/Documentation/userspace-api/ioctl/cdrom.rst
new file mode 100644
index 000000000..2ad91dbeb
--- /dev/null
+++ b/Documentation/userspace-api/ioctl/cdrom.rst
@@ -0,0 +1,1242 @@
+============================
+Summary of CDROM ioctl calls
+============================
+
+- Edward A. Falk <efalk@google.com>
+
+November, 2004
+
+This document attempts to describe the ioctl(2) calls supported by
+the CDROM layer.  These are by-and-large implemented (as of Linux 2.6)
+in drivers/cdrom/cdrom.c and drivers/block/scsi_ioctl.c
+
+ioctl values are listed in <linux/cdrom.h>.  As of this writing, they
+are as follows:
+
+	========================  ===============================================
+	CDROMPAUSE		  Pause Audio Operation
+	CDROMRESUME		  Resume paused Audio Operation
+	CDROMPLAYMSF		  Play Audio MSF (struct cdrom_msf)
+	CDROMPLAYTRKIND		  Play Audio Track/index (struct cdrom_ti)
+	CDROMREADTOCHDR		  Read TOC header (struct cdrom_tochdr)
+	CDROMREADTOCENTRY	  Read TOC entry (struct cdrom_tocentry)
+	CDROMSTOP		  Stop the cdrom drive
+	CDROMSTART		  Start the cdrom drive
+	CDROMEJECT		  Ejects the cdrom media
+	CDROMVOLCTRL		  Control output volume (struct cdrom_volctrl)
+	CDROMSUBCHNL		  Read subchannel data (struct cdrom_subchnl)
+	CDROMREADMODE2		  Read CDROM mode 2 data (2336 Bytes)
+				  (struct cdrom_read)
+	CDROMREADMODE1		  Read CDROM mode 1 data (2048 Bytes)
+				  (struct cdrom_read)
+	CDROMREADAUDIO		  (struct cdrom_read_audio)
+	CDROMEJECT_SW		  enable(1)/disable(0) auto-ejecting
+	CDROMMULTISESSION	  Obtain the start-of-last-session
+				  address of multi session disks
+				  (struct cdrom_multisession)
+	CDROM_GET_MCN		  Obtain the "Universal Product Code"
+				  if available (struct cdrom_mcn)
+	CDROM_GET_UPC		  Deprecated, use CDROM_GET_MCN instead.
+	CDROMRESET		  hard-reset the drive
+	CDROMVOLREAD		  Get the drive's volume setting
+				  (struct cdrom_volctrl)
+	CDROMREADRAW		  read data in raw mode (2352 Bytes)
+				  (struct cdrom_read)
+	CDROMREADCOOKED		  read data in cooked mode
+	CDROMSEEK		  seek msf address
+	CDROMPLAYBLK		  scsi-cd only, (struct cdrom_blk)
+	CDROMREADALL		  read all 2646 bytes
+	CDROMGETSPINDOWN	  return 4-bit spindown value
+	CDROMSETSPINDOWN	  set 4-bit spindown value
+	CDROMCLOSETRAY		  pendant of CDROMEJECT
+	CDROM_SET_OPTIONS	  Set behavior options
+	CDROM_CLEAR_OPTIONS	  Clear behavior options
+	CDROM_SELECT_SPEED	  Set the CD-ROM speed
+	CDROM_SELECT_DISC	  Select disc (for juke-boxes)
+	CDROM_MEDIA_CHANGED	  Check is media changed
+	CDROM_TIMED_MEDIA_CHANGE  Check if media changed
+				  since given time
+				  (struct cdrom_timed_media_change_info)
+	CDROM_DRIVE_STATUS	  Get tray position, etc.
+	CDROM_DISC_STATUS	  Get disc type, etc.
+	CDROM_CHANGER_NSLOTS	  Get number of slots
+	CDROM_LOCKDOOR		  lock or unlock door
+	CDROM_DEBUG		  Turn debug messages on/off
+	CDROM_GET_CAPABILITY	  get capabilities
+	CDROMAUDIOBUFSIZ	  set the audio buffer size
+	DVD_READ_STRUCT		  Read structure
+	DVD_WRITE_STRUCT	  Write structure
+	DVD_AUTH		  Authentication
+	CDROM_SEND_PACKET	  send a packet to the drive
+	CDROM_NEXT_WRITABLE	  get next writable block
+	CDROM_LAST_WRITTEN	  get last block written on disc
+	========================  ===============================================
+
+
+The information that follows was determined from reading kernel source
+code.  It is likely that some corrections will be made over time.
+
+------------------------------------------------------------------------------
+
+General:
+
+	Unless otherwise specified, all ioctl calls return 0 on success
+	and -1 with errno set to an appropriate value on error.  (Some
+	ioctls return non-negative data values.)
+
+	Unless otherwise specified, all ioctl calls return -1 and set
+	errno to EFAULT on a failed attempt to copy data to or from user
+	address space.
+
+	Individual drivers may return error codes not listed here.
+
+	Unless otherwise specified, all data structures and constants
+	are defined in <linux/cdrom.h>
+
+------------------------------------------------------------------------------
+
+
+CDROMPAUSE
+	Pause Audio Operation
+
+
+	usage::
+
+	  ioctl(fd, CDROMPAUSE, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+
+CDROMRESUME
+	Resume paused Audio Operation
+
+
+	usage::
+
+	  ioctl(fd, CDROMRESUME, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+
+CDROMPLAYMSF
+	Play Audio MSF
+
+	(struct cdrom_msf)
+
+
+	usage::
+
+	  struct cdrom_msf msf;
+
+	  ioctl(fd, CDROMPLAYMSF, &msf);
+
+	inputs:
+		cdrom_msf structure, describing a segment of music to play
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+	notes:
+		- MSF stands for minutes-seconds-frames
+		- LBA stands for logical block address
+		- Segment is described as start and end times, where each time
+		  is described as minutes:seconds:frames.
+		  A frame is 1/75 of a second.
+
+
+CDROMPLAYTRKIND
+	Play Audio Track/index
+
+	(struct cdrom_ti)
+
+
+	usage::
+
+	  struct cdrom_ti ti;
+
+	  ioctl(fd, CDROMPLAYTRKIND, &ti);
+
+	inputs:
+		cdrom_ti structure, describing a segment of music to play
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+	notes:
+		- Segment is described as start and end times, where each time
+		  is described as a track and an index.
+
+
+
+CDROMREADTOCHDR
+	Read TOC header
+
+	(struct cdrom_tochdr)
+
+
+	usage::
+
+	  cdrom_tochdr header;
+
+	  ioctl(fd, CDROMREADTOCHDR, &header);
+
+	inputs:
+		cdrom_tochdr structure
+
+
+	outputs:
+		cdrom_tochdr structure
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+
+
+CDROMREADTOCENTRY
+	Read TOC entry
+
+	(struct cdrom_tocentry)
+
+
+	usage::
+
+	  struct cdrom_tocentry entry;
+
+	  ioctl(fd, CDROMREADTOCENTRY, &entry);
+
+	inputs:
+		cdrom_tocentry structure
+
+
+	outputs:
+		cdrom_tocentry structure
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+	  - EINVAL	entry.cdte_format not CDROM_MSF or CDROM_LBA
+	  - EINVAL	requested track out of bounds
+	  - EIO		I/O error reading TOC
+
+	notes:
+		- TOC stands for Table Of Contents
+		- MSF stands for minutes-seconds-frames
+		- LBA stands for logical block address
+
+
+
+CDROMSTOP
+	Stop the cdrom drive
+
+
+	usage::
+
+	  ioctl(fd, CDROMSTOP, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+	notes:
+	  - Exact interpretation of this ioctl depends on the device,
+	    but most seem to spin the drive down.
+
+
+CDROMSTART
+	Start the cdrom drive
+
+
+	usage::
+
+	  ioctl(fd, CDROMSTART, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+	notes:
+	  - Exact interpretation of this ioctl depends on the device,
+	    but most seem to spin the drive up and/or close the tray.
+	    Other devices ignore the ioctl completely.
+
+
+CDROMEJECT
+	- Ejects the cdrom media
+
+
+	usage::
+
+	  ioctl(fd, CDROMEJECT, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error returns:
+	  - ENOSYS	cd drive not capable of ejecting
+	  - EBUSY	other processes are accessing drive, or door is locked
+
+	notes:
+		- See CDROM_LOCKDOOR, below.
+
+
+
+
+CDROMCLOSETRAY
+	pendant of CDROMEJECT
+
+
+	usage::
+
+	  ioctl(fd, CDROMCLOSETRAY, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error returns:
+	  - ENOSYS	cd drive not capable of closing the tray
+	  - EBUSY	other processes are accessing drive, or door is locked
+
+	notes:
+		- See CDROM_LOCKDOOR, below.
+
+
+
+
+CDROMVOLCTRL
+	Control output volume (struct cdrom_volctrl)
+
+
+	usage::
+
+	  struct cdrom_volctrl volume;
+
+	  ioctl(fd, CDROMVOLCTRL, &volume);
+
+	inputs:
+		cdrom_volctrl structure containing volumes for up to 4
+		channels.
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+
+
+CDROMVOLREAD
+	Get the drive's volume setting
+
+	(struct cdrom_volctrl)
+
+
+	usage::
+
+	  struct cdrom_volctrl volume;
+
+	  ioctl(fd, CDROMVOLREAD, &volume);
+
+	inputs:
+		none
+
+
+	outputs:
+		The current volume settings.
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+
+
+
+CDROMSUBCHNL
+	Read subchannel data
+
+	(struct cdrom_subchnl)
+
+
+	usage::
+
+	  struct cdrom_subchnl q;
+
+	  ioctl(fd, CDROMSUBCHNL, &q);
+
+	inputs:
+		cdrom_subchnl structure
+
+
+	outputs:
+		cdrom_subchnl structure
+
+
+	error return:
+	  - ENOSYS	cd drive not audio-capable.
+	  - EINVAL	format not CDROM_MSF or CDROM_LBA
+
+	notes:
+		- Format is converted to CDROM_MSF or CDROM_LBA
+		  as per user request on return
+
+
+
+CDROMREADRAW
+	read data in raw mode (2352 Bytes)
+
+	(struct cdrom_read)
+
+	usage::
+
+	  union {
+
+	    struct cdrom_msf msf;		/* input */
+	    char buffer[CD_FRAMESIZE_RAW];	/* return */
+	  } arg;
+	  ioctl(fd, CDROMREADRAW, &arg);
+
+	inputs:
+		cdrom_msf structure indicating an address to read.
+
+		Only the start values are significant.
+
+	outputs:
+		Data written to address provided by user.
+
+
+	error return:
+	  - EINVAL	address less than 0, or msf less than 0:2:0
+	  - ENOMEM	out of memory
+
+	notes:
+		- As of 2.6.8.1, comments in <linux/cdrom.h> indicate that this
+		  ioctl accepts a cdrom_read structure, but actual source code
+		  reads a cdrom_msf structure and writes a buffer of data to
+		  the same address.
+
+		- MSF values are converted to LBA values via this formula::
+
+		    lba = (((m * CD_SECS) + s) * CD_FRAMES + f) - CD_MSF_OFFSET;
+
+
+
+
+CDROMREADMODE1
+	Read CDROM mode 1 data (2048 Bytes)
+
+	(struct cdrom_read)
+
+	notes:
+		Identical to CDROMREADRAW except that block size is
+		CD_FRAMESIZE (2048) bytes
+
+
+
+CDROMREADMODE2
+	Read CDROM mode 2 data (2336 Bytes)
+
+	(struct cdrom_read)
+
+	notes:
+		Identical to CDROMREADRAW except that block size is
+		CD_FRAMESIZE_RAW0 (2336) bytes
+
+
+
+CDROMREADAUDIO
+	(struct cdrom_read_audio)
+
+	usage::
+
+	  struct cdrom_read_audio ra;
+
+	  ioctl(fd, CDROMREADAUDIO, &ra);
+
+	inputs:
+		cdrom_read_audio structure containing read start
+		point and length
+
+	outputs:
+		audio data, returned to buffer indicated by ra
+
+
+	error return:
+	  - EINVAL	format not CDROM_MSF or CDROM_LBA
+	  - EINVAL	nframes not in range [1 75]
+	  - ENXIO	drive has no queue (probably means invalid fd)
+	  - ENOMEM	out of memory
+
+
+CDROMEJECT_SW
+	enable(1)/disable(0) auto-ejecting
+
+
+	usage::
+
+	  int val;
+
+	  ioctl(fd, CDROMEJECT_SW, val);
+
+	inputs:
+		Flag specifying auto-eject flag.
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	Drive is not capable of ejecting.
+	  - EBUSY	Door is locked
+
+
+
+
+CDROMMULTISESSION
+	Obtain the start-of-last-session address of multi session disks
+
+	(struct cdrom_multisession)
+
+	usage::
+
+	  struct cdrom_multisession ms_info;
+
+	  ioctl(fd, CDROMMULTISESSION, &ms_info);
+
+	inputs:
+		cdrom_multisession structure containing desired
+
+	  format.
+
+	outputs:
+		cdrom_multisession structure is filled with last_session
+		information.
+
+	error return:
+	  - EINVAL	format not CDROM_MSF or CDROM_LBA
+
+
+CDROM_GET_MCN
+	Obtain the "Universal Product Code"
+	if available
+
+	(struct cdrom_mcn)
+
+
+	usage::
+
+	  struct cdrom_mcn mcn;
+
+	  ioctl(fd, CDROM_GET_MCN, &mcn);
+
+	inputs:
+		none
+
+
+	outputs:
+		Universal Product Code
+
+
+	error return:
+	  - ENOSYS	Drive is not capable of reading MCN data.
+
+	notes:
+		- Source code comments state::
+
+		    The following function is implemented, although very few
+		    audio discs give Universal Product Code information, which
+		    should just be the Medium Catalog Number on the box.  Note,
+		    that the way the code is written on the CD is /not/ uniform
+		    across all discs!
+
+
+
+
+CDROM_GET_UPC
+	CDROM_GET_MCN  (deprecated)
+
+
+	Not implemented, as of 2.6.8.1
+
+
+
+CDROMRESET
+	hard-reset the drive
+
+
+	usage::
+
+	  ioctl(fd, CDROMRESET, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
+	  - ENOSYS	Drive is not capable of resetting.
+
+
+
+
+CDROMREADCOOKED
+	read data in cooked mode
+
+
+	usage::
+
+	  u8 buffer[CD_FRAMESIZE]
+
+	  ioctl(fd, CDROMREADCOOKED, buffer);
+
+	inputs:
+		none
+
+
+	outputs:
+		2048 bytes of data, "cooked" mode.
+
+
+	notes:
+		Not implemented on all drives.
+
+
+
+
+
+CDROMREADALL
+	read all 2646 bytes
+
+
+	Same as CDROMREADCOOKED, but reads 2646 bytes.
+
+
+
+CDROMSEEK
+	seek msf address
+
+
+	usage::
+
+	  struct cdrom_msf msf;
+
+	  ioctl(fd, CDROMSEEK, &msf);
+
+	inputs:
+		MSF address to seek to.
+
+
+	outputs:
+		none
+
+
+
+
+CDROMPLAYBLK
+	scsi-cd only
+
+	(struct cdrom_blk)
+
+
+	usage::
+
+	  struct cdrom_blk blk;
+
+	  ioctl(fd, CDROMPLAYBLK, &blk);
+
+	inputs:
+		Region to play
+
+
+	outputs:
+		none
+
+
+
+
+CDROMGETSPINDOWN
+	Obsolete, was ide-cd only
+
+
+	usage::
+
+	  char spindown;
+
+	  ioctl(fd, CDROMGETSPINDOWN, &spindown);
+
+	inputs:
+		none
+
+
+	outputs:
+		The value of the current 4-bit spindown value.
+
+
+
+
+
+CDROMSETSPINDOWN
+	Obsolete, was ide-cd only
+
+
+	usage::
+
+	  char spindown
+
+	  ioctl(fd, CDROMSETSPINDOWN, &spindown);
+
+	inputs:
+		4-bit value used to control spindown (TODO: more detail here)
+
+
+	outputs:
+		none
+
+
+
+
+
+
+CDROM_SET_OPTIONS
+	Set behavior options
+
+
+	usage::
+
+	  int options;
+
+	  ioctl(fd, CDROM_SET_OPTIONS, options);
+
+	inputs:
+		New values for drive options.  The logical 'or' of:
+
+	    ==============      ==================================
+	    CDO_AUTO_CLOSE	close tray on first open(2)
+	    CDO_AUTO_EJECT	open tray on last release
+	    CDO_USE_FFLAGS	use O_NONBLOCK information on open
+	    CDO_LOCK		lock tray on open files
+	    CDO_CHECK_TYPE	check type on open for data
+	    ==============      ==================================
+
+	outputs:
+		Returns the resulting options settings in the
+		ioctl return value.  Returns -1 on error.
+
+	error return:
+	  - ENOSYS	selected option(s) not supported by drive.
+
+
+
+
+CDROM_CLEAR_OPTIONS
+	Clear behavior options
+
+
+	Same as CDROM_SET_OPTIONS, except that selected options are
+	turned off.
+
+
+
+CDROM_SELECT_SPEED
+	Set the CD-ROM speed
+
+
+	usage::
+
+	  int speed;
+
+	  ioctl(fd, CDROM_SELECT_SPEED, speed);
+
+	inputs:
+		New drive speed.
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - ENOSYS	speed selection not supported by drive.
+
+
+
+CDROM_SELECT_DISC
+	Select disc (for juke-boxes)
+
+
+	usage::
+
+	  int disk;
+
+	  ioctl(fd, CDROM_SELECT_DISC, disk);
+
+	inputs:
+		Disk to load into drive.
+
+
+	outputs:
+		none
+
+
+	error return:
+	  - EINVAL	Disk number beyond capacity of drive
+
+
+
+CDROM_MEDIA_CHANGED
+	Check is media changed
+
+
+	usage::
+
+	  int slot;
+
+	  ioctl(fd, CDROM_MEDIA_CHANGED, slot);
+
+	inputs:
+		Slot number to be tested, always zero except for jukeboxes.
+
+		May also be special values CDSL_NONE or CDSL_CURRENT
+
+	outputs:
+		Ioctl return value is 0 or 1 depending on whether the media
+
+	  has been changed, or -1 on error.
+
+	error returns:
+	  - ENOSYS	Drive can't detect media change
+	  - EINVAL	Slot number beyond capacity of drive
+	  - ENOMEM	Out of memory
+
+
+
+CDROM_DRIVE_STATUS
+	Get tray position, etc.
+
+
+	usage::
+
+	  int slot;
+
+	  ioctl(fd, CDROM_DRIVE_STATUS, slot);
+
+	inputs:
+		Slot number to be tested, always zero except for jukeboxes.
+
+		May also be special values CDSL_NONE or CDSL_CURRENT
+
+	outputs:
+		Ioctl return value will be one of the following values
+
+	  from <linux/cdrom.h>:
+
+	    =================== ==========================
+	    CDS_NO_INFO		Information not available.
+	    CDS_NO_DISC
+	    CDS_TRAY_OPEN
+	    CDS_DRIVE_NOT_READY
+	    CDS_DISC_OK
+	    -1			error
+	    =================== ==========================
+
+	error returns:
+	  - ENOSYS	Drive can't detect drive status
+	  - EINVAL	Slot number beyond capacity of drive
+	  - ENOMEM	Out of memory
+
+
+
+
+CDROM_DISC_STATUS
+	Get disc type, etc.
+
+
+	usage::
+
+	  ioctl(fd, CDROM_DISC_STATUS, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		Ioctl return value will be one of the following values
+
+	  from <linux/cdrom.h>:
+
+	    - CDS_NO_INFO
+	    - CDS_AUDIO
+	    - CDS_MIXED
+	    - CDS_XA_2_2
+	    - CDS_XA_2_1
+	    - CDS_DATA_1
+
+	error returns:
+		none at present
+
+	notes:
+	    - Source code comments state::
+
+
+		Ok, this is where problems start.  The current interface for
+		the CDROM_DISC_STATUS ioctl is flawed.  It makes the false
+		assumption that CDs are all CDS_DATA_1 or all CDS_AUDIO, etc.
+		Unfortunately, while this is often the case, it is also
+		very common for CDs to have some tracks with data, and some
+		tracks with audio.	Just because I feel like it, I declare
+		the following to be the best way to cope.  If the CD has
+		ANY data tracks on it, it will be returned as a data CD.
+		If it has any XA tracks, I will return it as that.	Now I
+		could simplify this interface by combining these returns with
+		the above, but this more clearly demonstrates the problem
+		with the current interface.  Too bad this wasn't designed
+		to use bitmasks...	       -Erik
+
+		Well, now we have the option CDS_MIXED: a mixed-type CD.
+		User level programmers might feel the ioctl is not very
+		useful.
+				---david
+
+
+
+
+CDROM_CHANGER_NSLOTS
+	Get number of slots
+
+
+	usage::
+
+	  ioctl(fd, CDROM_CHANGER_NSLOTS, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		The ioctl return value will be the number of slots in a
+		CD changer.  Typically 1 for non-multi-disk devices.
+
+	error returns:
+		none
+
+
+
+CDROM_LOCKDOOR
+	lock or unlock door
+
+
+	usage::
+
+	  int lock;
+
+	  ioctl(fd, CDROM_LOCKDOOR, lock);
+
+	inputs:
+		Door lock flag, 1=lock, 0=unlock
+
+
+	outputs:
+		none
+
+
+	error returns:
+	  - EDRIVE_CANT_DO_THIS
+
+				Door lock function not supported.
+	  - EBUSY
+
+				Attempt to unlock when multiple users
+				have the drive open and not CAP_SYS_ADMIN
+
+	notes:
+		As of 2.6.8.1, the lock flag is a global lock, meaning that
+		all CD drives will be locked or unlocked together.  This is
+		probably a bug.
+
+		The EDRIVE_CANT_DO_THIS value is defined in <linux/cdrom.h>
+		and is currently (2.6.8.1) the same as EOPNOTSUPP
+
+
+
+CDROM_DEBUG
+	Turn debug messages on/off
+
+
+	usage::
+
+	  int debug;
+
+	  ioctl(fd, CDROM_DEBUG, debug);
+
+	inputs:
+		Cdrom debug flag, 0=disable, 1=enable
+
+
+	outputs:
+		The ioctl return value will be the new debug flag.
+
+
+	error return:
+	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
+
+
+
+CDROM_GET_CAPABILITY
+	get capabilities
+
+
+	usage::
+
+	  ioctl(fd, CDROM_GET_CAPABILITY, 0);
+
+
+	inputs:
+		none
+
+
+	outputs:
+		The ioctl return value is the current device capability
+		flags.  See CDC_CLOSE_TRAY, CDC_OPEN_TRAY, etc.
+
+
+
+CDROMAUDIOBUFSIZ
+	set the audio buffer size
+
+
+	usage::
+
+	  int arg;
+
+	  ioctl(fd, CDROMAUDIOBUFSIZ, val);
+
+	inputs:
+		New audio buffer size
+
+
+	outputs:
+		The ioctl return value is the new audio buffer size, or -1
+		on error.
+
+	error return:
+	  - ENOSYS	Not supported by this driver.
+
+	notes:
+		Not supported by all drivers.
+
+
+
+
+DVD_READ_STRUCT			Read structure
+
+	usage::
+
+	  dvd_struct s;
+
+	  ioctl(fd, DVD_READ_STRUCT, &s);
+
+	inputs:
+		dvd_struct structure, containing:
+
+	    =================== ==========================================
+	    type		specifies the information desired, one of
+				DVD_STRUCT_PHYSICAL, DVD_STRUCT_COPYRIGHT,
+				DVD_STRUCT_DISCKEY, DVD_STRUCT_BCA,
+				DVD_STRUCT_MANUFACT
+	    physical.layer_num	desired layer, indexed from 0
+	    copyright.layer_num	desired layer, indexed from 0
+	    disckey.agid
+	    =================== ==========================================
+
+	outputs:
+		dvd_struct structure, containing:
+
+	    =================== ================================
+	    physical		for type == DVD_STRUCT_PHYSICAL
+	    copyright		for type == DVD_STRUCT_COPYRIGHT
+	    disckey.value	for type == DVD_STRUCT_DISCKEY
+	    bca.{len,value}	for type == DVD_STRUCT_BCA
+	    manufact.{len,valu}	for type == DVD_STRUCT_MANUFACT
+	    =================== ================================
+
+	error returns:
+	  - EINVAL	physical.layer_num exceeds number of layers
+	  - EIO		Received invalid response from drive
+
+
+
+DVD_WRITE_STRUCT		Write structure
+
+	Not implemented, as of 2.6.8.1
+
+
+
+DVD_AUTH			Authentication
+
+	usage::
+
+	  dvd_authinfo ai;
+
+	  ioctl(fd, DVD_AUTH, &ai);
+
+	inputs:
+		dvd_authinfo structure.  See <linux/cdrom.h>
+
+
+	outputs:
+		dvd_authinfo structure.
+
+
+	error return:
+	  - ENOTTY	ai.type not recognized.
+
+
+
+CDROM_SEND_PACKET
+	send a packet to the drive
+
+
+	usage::
+
+	  struct cdrom_generic_command cgc;
+
+	  ioctl(fd, CDROM_SEND_PACKET, &cgc);
+
+	inputs:
+		cdrom_generic_command structure containing the packet to send.
+
+
+	outputs:
+		none
+
+	  cdrom_generic_command structure containing results.
+
+	error return:
+	  - EIO
+
+			command failed.
+	  - EPERM
+
+			Operation not permitted, either because a
+			write command was attempted on a drive which
+			is opened read-only, or because the command
+			requires CAP_SYS_RAWIO
+	  - EINVAL
+
+			cgc.data_direction not set
+
+
+
+CDROM_NEXT_WRITABLE
+	get next writable block
+
+
+	usage::
+
+	  long next;
+
+	  ioctl(fd, CDROM_NEXT_WRITABLE, &next);
+
+	inputs:
+		none
+
+
+	outputs:
+		The next writable block.
+
+
+	notes:
+		If the device does not support this ioctl directly, the
+
+	  ioctl will return CDROM_LAST_WRITTEN + 7.
+
+
+
+CDROM_LAST_WRITTEN
+	get last block written on disc
+
+
+	usage::
+
+	  long last;
+
+	  ioctl(fd, CDROM_LAST_WRITTEN, &last);
+
+	inputs:
+		none
+
+
+	outputs:
+		The last block written on disc
+
+
+	notes:
+		If the device does not support this ioctl directly, the
+		result is derived from the disc's table of contents.  If the
+		table of contents can't be read, this ioctl returns an
+		error.