[PATCH v2 8/8] scsi: sr: wait for the medium to become ready

[Michal Suchanek]

Use the autoclose IOCLT provided by cdrom driver to wait for drive to
close in open_finish, and attempt to open once more after the door
closes.

Signed-off-by: Michal Suchanek <msucha...@suse.de>
---
 drivers/scsi/sr.c | 54 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 42 insertions(+), 12 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 8090c5bdec09..34d9a818b9e0 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -521,29 +521,58 @@ static blk_status_t sr_init_command(struct scsi_cmnd 
*SCpnt)
        return ret;
 }
 
-static int sr_block_open(struct block_device *bdev, fmode_t mode)
+static int __sr_block_open(struct block_device *bdev, fmode_t mode)
 {
-       struct scsi_cd *cd;
-       struct scsi_device *sdev;
-       int ret = -ENXIO;
-
-       cd = scsi_cd_get(bdev->bd_disk);
-       if (!cd)
-               goto out;
+       struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
+       int ret;
 
-       sdev = cd->device;
-       scsi_autopm_get_device(sdev);
        check_disk_change(bdev);
 
        mutex_lock(&sr_mutex);
        ret = cdrom_open(&cd->cdi, bdev, mode);
        mutex_unlock(&sr_mutex);
 
+       return ret;
+}
+
+static int sr_block_open(struct block_device *bdev, fmode_t mode)
+{
+       struct scsi_cd *cd = scsi_cd_get(bdev->bd_disk);
+       struct scsi_device *sdev;
+       int ret;
+
+       if (!cd)
+               return -ENXIO;
+
+       sdev = cd->device;
+       scsi_autopm_get_device(sdev);
+       ret = __sr_block_open(bdev, mode);
        scsi_autopm_put_device(sdev);
-       if (ret)
+
+       if (ret == -ERESTARTSYS)
                scsi_cd_put(cd);
 
-out:
+       return ret;
+}
+
+static int sr_block_open_finish(struct block_device *bdev, fmode_t mode,
+                               int ret)
+{
+       struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
+
+       /* wait for drive to get ready */
+       if ((ret == -ENOMEDIUM) && !(mode & FMODE_NDELAY)) {
+               struct scsi_device *sdev = cd->device;
+               /*
+                * Cannot use sr_block_ioctl because it locks sr_mutex blocking
+                * out any processes trying to access the drive
+                */
+               scsi_autopm_get_device(sdev);
+               cdrom_ioctl(&cd->cdi, bdev, mode, CDROM_AUTOCLOSE, 0);
+               ret = __sr_block_open(bdev, mode);
+               scsi_autopm_put_device(sdev);
+       }
+
        return ret;
 }
 
@@ -639,6 +668,7 @@ static const struct block_device_operations sr_bdops =
 {
        .owner          = THIS_MODULE,
        .open           = sr_block_open,
+       .open_finish    = sr_block_open_finish,
        .release        = sr_block_release,
        .ioctl          = sr_block_ioctl,
        .check_events   = sr_block_check_events,
-- 
2.23.0