cdrom: remove the unused cdrom_media_changed function

As well as the ->media_changed method.  All these are left over from
before the drivers were switched over to the check_events scheme.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/cdrom/cdrom-standard.rst

@@ -157,7 +157,6 @@ with the kernel as a block device by registering the following general
 		cdrom_release,		/∗ release ∗/
 		NULL,			/∗ fsync ∗/
 		NULL,			/∗ fasync ∗/
-		cdrom_media_changed,	/∗ media change ∗/
 		NULL			/∗ revalidate ∗/
 	};
 
@@ -366,19 +365,6 @@ which may or may not be in the drive). If the drive is not a changer,
 	CDS_DRIVE_NOT_READY	/* something is wrong, tray is moving? */
 	CDS_DISC_OK		/* a disc is loaded and everything is fine */
 
-::
-
-	int media_changed(struct cdrom_device_info *cdi, int disc_nr)
-
-This function is very similar to the original function in $struct
-file_operations*. It returns 1 if the medium of the device *cdi->dev*
-has changed since the last call, and 0 otherwise. The parameter
-*disc_nr* identifies a specific slot in a juke-box, it should be
-ignored for single-disc drives. Note that by `re-routing` this
-function through *cdrom_media_changed()*, we can implement separate
-queues for the VFS and a new *ioctl()* function that can report device
-changes to software (e. g., an auto-mounting daemon).
-
 ::
 
 	int tray_move(struct cdrom_device_info *cdi, int position)
@@ -917,9 +903,7 @@ commands can be identified by the underscores in their names.
 	maximum number of discs in the juke-box found in the *cdrom_dops*.
 `CDROM_MEDIA_CHANGED`
 	Returns 1 if a disc has been changed since the last call.
-	Note that calls to *cdrom_media_changed* by the VFS are treated
+	For juke-boxes, an extra argument *arg*
-	by an independent queue, so both mechanisms will detect a
-	media change once. For juke-boxes, an extra argument *arg*
 	specifies the slot for which the information is given. The special
 	value *CDSL_CURRENT* requests that information about the currently
 	selected slot be returned.

drivers/cdrom/cdrom.c

@@ -605,7 +605,7 @@ int register_cdrom(struct gendisk *disk, struct cdrom_device_info *cdi)
 	disk->cdi = cdi;
 
 	ENSURE(cdo, drive_status, CDC_DRIVE_STATUS);
-	if (cdo->check_events == NULL && cdo->media_changed == NULL)
+	if (cdo->check_events == NULL)
 		WARN_ON_ONCE(cdo->capability & (CDC_MEDIA_CHANGED | CDC_SELECT_DISC));
 	ENSURE(cdo, tray_move, CDC_CLOSE_TRAY | CDC_OPEN_TRAY);
 	ENSURE(cdo, lock_door, CDC_LOCK);
@@ -1419,8 +1419,6 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
 
 	if (cdi->ops->check_events)
 		cdi->ops->check_events(cdi, 0, slot);
-	else
-		cdi->ops->media_changed(cdi, slot);
 
 	if (slot == CDSL_NONE) {
 		/* set media changed bits, on both queues */
@@ -1517,13 +1515,10 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 		return ret;
 
 	/* changed since last call? */
-	if (cdi->ops->check_events) {
+	BUG_ON(!queue);	/* shouldn't be called from VFS path */
-		BUG_ON(!queue);	/* shouldn't be called from VFS path */
+	cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
-		cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
+	changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
-		changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
+	cdi->ioctl_events = 0;
-		cdi->ioctl_events = 0;
-	} else
-		changed = cdi->ops->media_changed(cdi, CDSL_CURRENT);
 
 	if (changed) {
 		cdi->mc_flags = 0x3;    /* set bit on both queues */
@@ -1535,18 +1530,6 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 	return ret;
 }
 
-int cdrom_media_changed(struct cdrom_device_info *cdi)
-{
-	/* This talks to the VFS, which doesn't like errors - just 1 or 0.  
-	 * Returning "0" is always safe (media hasn't been changed). Do that 
-	 * if the low-level cdrom driver dosn't support media changed. */ 
-	if (cdi == NULL || cdi->ops->media_changed == NULL)
-		return 0;
-	if (!CDROM_CAN(CDC_MEDIA_CHANGED))
-		return 0;
-	return media_changed(cdi, 0);
-}
-
 /* Requests to the low-level drivers will /always/ be done in the
    following format convention:
 
@@ -3464,7 +3447,6 @@ EXPORT_SYMBOL(unregister_cdrom);
 EXPORT_SYMBOL(cdrom_open);
 EXPORT_SYMBOL(cdrom_release);
 EXPORT_SYMBOL(cdrom_ioctl);
-EXPORT_SYMBOL(cdrom_media_changed);
 EXPORT_SYMBOL(cdrom_number_of_slots);
 EXPORT_SYMBOL(cdrom_mode_select);
 EXPORT_SYMBOL(cdrom_mode_sense);

include/linux/cdrom.h

@@ -73,7 +73,6 @@ struct cdrom_device_ops {
 	int (*drive_status) (struct cdrom_device_info *, int);
 	unsigned int (*check_events) (struct cdrom_device_info *cdi,
 				      unsigned int clearing, int slot);
-	int (*media_changed) (struct cdrom_device_info *, int);
 	int (*tray_move) (struct cdrom_device_info *, int);
 	int (*lock_door) (struct cdrom_device_info *, int);
 	int (*select_speed) (struct cdrom_device_info *, int);
@@ -107,7 +106,6 @@ extern int cdrom_ioctl(struct cdrom_device_info *cdi, struct block_device *bdev,
 		       fmode_t mode, unsigned int cmd, unsigned long arg);
 extern unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
 				       unsigned int clearing);
-extern int cdrom_media_changed(struct cdrom_device_info *);
 
 extern int register_cdrom(struct gendisk *disk, struct cdrom_device_info *cdi);
 extern void unregister_cdrom(struct cdrom_device_info *cdi);