diff options
| -rw-r--r-- | drivers/cdrom/cdrom.c | 55 | ||||
| -rw-r--r-- | include/linux/cdrom.h | 6 |
2 files changed, 58 insertions, 3 deletions
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c index af13c62dc473..1ea8f8d363c6 100644 --- a/drivers/cdrom/cdrom.c +++ b/drivers/cdrom/cdrom.c @@ -1348,7 +1348,10 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot) if (!CDROM_CAN(CDC_SELECT_DISC)) return -EDRIVE_CANT_DO_THIS; - (void) cdi->ops->media_changed(cdi, 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 */ @@ -1392,6 +1395,41 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot) return slot; } +/* + * As cdrom implements an extra ioctl consumer for media changed + * event, it needs to buffer ->check_events() output, such that event + * is not lost for both the usual VFS and ioctl paths. + * cdi->{vfs|ioctl}_events are used to buffer pending events for each + * path. + * + * XXX: Locking is non-existent. cdi->ops->check_events() can be + * called in parallel and buffering fields are accessed without any + * exclusion. The original media_changed code had the same problem. + * It might be better to simply deprecate CDROM_MEDIA_CHANGED ioctl + * and remove this cruft altogether. It doesn't have much usefulness + * at this point. + */ +static void cdrom_update_events(struct cdrom_device_info *cdi, + unsigned int clearing) +{ + unsigned int events; + + events = cdi->ops->check_events(cdi, clearing, CDSL_CURRENT); + cdi->vfs_events |= events; + cdi->ioctl_events |= events; +} + +unsigned int cdrom_check_events(struct cdrom_device_info *cdi, + unsigned int clearing) +{ + unsigned int events; + + cdrom_update_events(cdi, clearing); + events = cdi->vfs_events; + cdi->vfs_events = 0; + return events; +} + /* We want to make media_changed accessible to the user through an * ioctl. The main problem now is that we must double-buffer the * low-level implementation, to assure that the VFS and the user both @@ -1403,15 +1441,26 @@ int media_changed(struct cdrom_device_info *cdi, int queue) { unsigned int mask = (1 << (queue & 1)); int ret = !!(cdi->mc_flags & mask); + bool changed; if (!CDROM_CAN(CDC_MEDIA_CHANGED)) - return ret; + return ret; + /* changed since last call? */ - if (cdi->ops->media_changed(cdi, CDSL_CURRENT)) { + if (cdi->ops->check_events) { + BUG_ON(!queue); /* shouldn't be called from VFS path */ + cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE); + changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE; + cdi->ioctl_events = 0; + } else + changed = cdi->ops->media_changed(cdi, CDSL_CURRENT); + + if (changed) { cdi->mc_flags = 0x3; /* set bit on both queues */ ret |= 1; cdi->media_written = 0; } + cdi->mc_flags &= ~mask; /* clear bit */ return ret; } diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h index 78e904796622..35eae4b67503 100644 --- a/include/linux/cdrom.h +++ b/include/linux/cdrom.h @@ -946,6 +946,8 @@ struct cdrom_device_info { /* device-related storage */ unsigned int options : 30; /* options flags */ unsigned mc_flags : 2; /* media change buffer flags */ + unsigned int vfs_events; /* cached events for vfs path */ + unsigned int ioctl_events; /* cached events for ioctl path */ int use_count; /* number of times device opened */ char name[20]; /* name of the device type */ /* per-device flags */ @@ -965,6 +967,8 @@ struct cdrom_device_ops { int (*open) (struct cdrom_device_info *, int); void (*release) (struct cdrom_device_info *); 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); @@ -993,6 +997,8 @@ extern int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev, extern void cdrom_release(struct cdrom_device_info *cdi, fmode_t mode); 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 cdrom_device_info *cdi); |