cdrom: add ->check_events() support
In principle, cdrom just needs to pass through ->check_events() but CDROM_MEDIA_CHANGED ioctl makes things a bit more complex. Just as with ->media_changed() support, cdrom code needs to buffer the events and serve them to ioctl and vfs as requested. As the code has to deal with both ->check_events() and ->media_changed(), and vfs and ioctl event buffering, this patch adds check_events caching on top of the existing cdi->mc_flags buffering. It may be a good idea to deprecate CDROM_MEDIA_CHANGED ioctl and remove all this mess. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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@ -1348,7 +1348,10 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
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if (!CDROM_CAN(CDC_SELECT_DISC))
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if (!CDROM_CAN(CDC_SELECT_DISC))
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return -EDRIVE_CANT_DO_THIS;
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return -EDRIVE_CANT_DO_THIS;
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(void) cdi->ops->media_changed(cdi, slot);
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if (cdi->ops->check_events)
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cdi->ops->check_events(cdi, 0, slot);
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else
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cdi->ops->media_changed(cdi, slot);
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if (slot == CDSL_NONE) {
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if (slot == CDSL_NONE) {
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/* set media changed bits, on both queues */
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/* set media changed bits, on both queues */
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@ -1392,6 +1395,41 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
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return slot;
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return slot;
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}
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}
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/*
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* As cdrom implements an extra ioctl consumer for media changed
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* event, it needs to buffer ->check_events() output, such that event
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* is not lost for both the usual VFS and ioctl paths.
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* cdi->{vfs|ioctl}_events are used to buffer pending events for each
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* path.
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*
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* XXX: Locking is non-existent. cdi->ops->check_events() can be
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* called in parallel and buffering fields are accessed without any
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* exclusion. The original media_changed code had the same problem.
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* It might be better to simply deprecate CDROM_MEDIA_CHANGED ioctl
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* and remove this cruft altogether. It doesn't have much usefulness
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* at this point.
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*/
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static void cdrom_update_events(struct cdrom_device_info *cdi,
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unsigned int clearing)
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{
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unsigned int events;
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events = cdi->ops->check_events(cdi, clearing, CDSL_CURRENT);
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cdi->vfs_events |= events;
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cdi->ioctl_events |= events;
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}
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unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
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unsigned int clearing)
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{
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unsigned int events;
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cdrom_update_events(cdi, clearing);
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events = cdi->vfs_events;
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cdi->vfs_events = 0;
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return events;
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}
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/* We want to make media_changed accessible to the user through an
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/* We want to make media_changed accessible to the user through an
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* ioctl. The main problem now is that we must double-buffer the
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* ioctl. The main problem now is that we must double-buffer the
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* low-level implementation, to assure that the VFS and the user both
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* low-level implementation, to assure that the VFS and the user both
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@ -1403,15 +1441,26 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
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{
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{
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unsigned int mask = (1 << (queue & 1));
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unsigned int mask = (1 << (queue & 1));
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int ret = !!(cdi->mc_flags & mask);
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int ret = !!(cdi->mc_flags & mask);
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bool changed;
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if (!CDROM_CAN(CDC_MEDIA_CHANGED))
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if (!CDROM_CAN(CDC_MEDIA_CHANGED))
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return ret;
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return ret;
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/* changed since last call? */
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/* changed since last call? */
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if (cdi->ops->media_changed(cdi, CDSL_CURRENT)) {
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if (cdi->ops->check_events) {
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BUG_ON(!queue); /* shouldn't be called from VFS path */
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cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
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changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
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cdi->ioctl_events = 0;
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} else
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changed = cdi->ops->media_changed(cdi, CDSL_CURRENT);
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if (changed) {
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cdi->mc_flags = 0x3; /* set bit on both queues */
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cdi->mc_flags = 0x3; /* set bit on both queues */
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ret |= 1;
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ret |= 1;
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cdi->media_written = 0;
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cdi->media_written = 0;
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}
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}
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cdi->mc_flags &= ~mask; /* clear bit */
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cdi->mc_flags &= ~mask; /* clear bit */
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return ret;
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return ret;
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}
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}
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@ -946,6 +946,8 @@ struct cdrom_device_info {
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/* device-related storage */
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/* device-related storage */
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unsigned int options : 30; /* options flags */
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unsigned int options : 30; /* options flags */
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unsigned mc_flags : 2; /* media change buffer flags */
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unsigned mc_flags : 2; /* media change buffer flags */
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unsigned int vfs_events; /* cached events for vfs path */
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unsigned int ioctl_events; /* cached events for ioctl path */
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int use_count; /* number of times device opened */
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int use_count; /* number of times device opened */
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char name[20]; /* name of the device type */
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char name[20]; /* name of the device type */
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/* per-device flags */
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/* per-device flags */
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@ -965,6 +967,8 @@ struct cdrom_device_ops {
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int (*open) (struct cdrom_device_info *, int);
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int (*open) (struct cdrom_device_info *, int);
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void (*release) (struct cdrom_device_info *);
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void (*release) (struct cdrom_device_info *);
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int (*drive_status) (struct cdrom_device_info *, int);
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int (*drive_status) (struct cdrom_device_info *, int);
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unsigned int (*check_events) (struct cdrom_device_info *cdi,
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unsigned int clearing, int slot);
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int (*media_changed) (struct cdrom_device_info *, int);
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int (*media_changed) (struct cdrom_device_info *, int);
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int (*tray_move) (struct cdrom_device_info *, int);
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int (*tray_move) (struct cdrom_device_info *, int);
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int (*lock_door) (struct cdrom_device_info *, int);
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int (*lock_door) (struct cdrom_device_info *, int);
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@ -993,6 +997,8 @@ extern int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev,
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extern void cdrom_release(struct cdrom_device_info *cdi, fmode_t mode);
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extern void cdrom_release(struct cdrom_device_info *cdi, fmode_t mode);
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extern int cdrom_ioctl(struct cdrom_device_info *cdi, struct block_device *bdev,
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extern int cdrom_ioctl(struct cdrom_device_info *cdi, struct block_device *bdev,
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fmode_t mode, unsigned int cmd, unsigned long arg);
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fmode_t mode, unsigned int cmd, unsigned long arg);
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extern unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
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unsigned int clearing);
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extern int cdrom_media_changed(struct cdrom_device_info *);
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extern int cdrom_media_changed(struct cdrom_device_info *);
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extern int register_cdrom(struct cdrom_device_info *cdi);
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extern int register_cdrom(struct cdrom_device_info *cdi);
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