[PATCH v3 7/7] scsi: sr: wait for the medium to become ready

Michal Suchanek
2019-10-25T11:22:01Z

Use the autoclose function 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 <msuchanek@suse.de>
---
v3: use function call rather than IOCTL
---
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 07c319494bf4..d144ad085b35 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -522,29 +522,58 @@ 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_autoclose(&cd->cdi);
+ ret = __sr_block_open(bdev, mode);
+ scsi_autopm_put_device(sdev);
+ }
+
return ret;
}

@@ -640,6 +669,7 @@ 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