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SubjectRe: [PATCH 7/8] sr: implement sr_check_events()
On 08/12/10 19:57, Tejun Heo wrote:
> Replace sr_media_change() with sr_check_events(). It normally only
> uses GET_EVENT_STATUS_NOTIFICATION to check both media change and
> eject request. If @clearing includes DISK_EVENT_MEDIA_CHANGE, it
> issues TUR and compares whether media presence has changed. The SCSI
> specific media change uevent is kept for compatibility.
>
> sr_media_change() was doing both media change check and revalidation.
> The revalidation part is split into sr_block_revalidate_disk().
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Kay Sievers <kay.sievers@vrfy.org>
> ---
> drivers/scsi/sr.c | 147 +++++++++++++++++++++++++++++++++------------------
> drivers/scsi/sr.h | 2 +-
> include/scsi/scsi.h | 1 +
> 3 files changed, 98 insertions(+), 52 deletions(-)

This breaks growisofs:
:-( /dev/dvd: CD_ROM_MEDIA_CHANGED ioctl failed: Inappropriate ioctl for device

SR_CAPABILITIES in sr.c includes CDC_MEDIA_CHANGED but cdrom.c removes
this capability in register_cdrom because there is no media_changed op:
ENSURE(media_changed, CDC_MEDIA_CHANGED);

The ioctl function cdrom_ioctl_media_changed() then returns -ENOSYS.

The media_changed() function again checks this capability but never uses
the media_changed op if the check_events op exists.

The cdrom_media_changed() function requires the media_changed op but
then calls media_changed().

It looks like cdrom_select_disc() is going to dereference the NULL
media_changed pointer if both check_events and media_changed don't
exist.

> diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
> index f6d8ee4..1e4b9b1 100644
> --- a/drivers/scsi/sr.c
> +++ b/drivers/scsi/sr.c
> @@ -104,14 +104,15 @@ static void sr_release(struct cdrom_device_info *);
> static void get_sectorsize(struct scsi_cd *);
> static void get_capabilities(struct scsi_cd *);
>
> -static int sr_media_change(struct cdrom_device_info *, int);
> +static unsigned int sr_check_events(struct cdrom_device_info *cdi,
> + unsigned int clearing, int slot);
> static int sr_packet(struct cdrom_device_info *, struct packet_command *);
>
> static struct cdrom_device_ops sr_dops = {
> .open = sr_open,
> .release = sr_release,
> .drive_status = sr_drive_status,
> - .media_changed = sr_media_change,
> + .check_events = sr_check_events,
> .tray_move = sr_tray_move,
> .lock_door = sr_lock_door,
> .select_speed = sr_select_speed,
> @@ -165,69 +166,96 @@ static void scsi_cd_put(struct scsi_cd *cd)
> mutex_unlock(&sr_ref_mutex);
> }

--
Simon Arlott


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