[PATCH v3 4/7] cdrom: export autoclose logic as a separate function

Michal Suchanek
2019-10-25T11:21:56Z

This allows the sr driver to call it without blocking other processes
accessing the device. This solves a issue with process waiting in open()
on broken drive to close the tray blocking out all access to the device,
including nonblocking access to determine drive status.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v2: new patch
v3:
- change IOCTL to export
- fix the logic about reporting cdroms inability to close tray
---
drivers/cdrom/cdrom.c | 87 +++++++++++++++++++++++++------------------
include/linux/cdrom.h | 1 +
2 files changed, 52 insertions(+), 36 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 27f4fce22781..a494f44fcf1f 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1070,46 +1070,16 @@ static int open_for_common(struct cdrom_device_info *cdi, tracktype *tracks)
cd_dbg(CD_OPEN, "drive_status=%d\n", ret);
if (ret == CDS_TRAY_OPEN) {
cd_dbg(CD_OPEN, "the tray is open...\n");
- /* can/may i close it? */
- if (CDROM_CAN(CDC_CLOSE_TRAY) &&
- cdi->options & CDO_AUTO_CLOSE) {
- cd_dbg(CD_OPEN, "trying to close the tray\n");
- ret = cdrom_tray_close(cdi);
- if (ret == -ERESTARTSYS)
- return ret;
- if (ret) {
- cd_dbg(CD_OPEN, "bummer. tried to close the tray but failed.\n");
- /* Ignore the error from the low
- level driver. We don't care why it
- couldn't close the tray. We only care
- that there is no disc in the drive,
- since that is the _REAL_ problem here.*/
- return -ENOMEDIUM;
- }
- } else {
- cd_dbg(CD_OPEN, "bummer. this drive can't close the tray.\n");
- return -ENOMEDIUM;
- }
- /* Ok, the door should be closed now.. Check again */
- ret = cdo->drive_status(cdi, CDSL_CURRENT);
- if ((ret == CDS_NO_DISC) || (ret==CDS_TRAY_OPEN)) {
- cd_dbg(CD_OPEN, "bummer. the tray is still not closed.\n");
- cd_dbg(CD_OPEN, "tray might not contain a medium\n");
- return -ENOMEDIUM;
- }
- cd_dbg(CD_OPEN, "the tray is now closed\n");
+ return -ENOMEDIUM;
}
- /* the door should be closed now, check for the disc */
if (ret == CDS_DRIVE_NOT_READY) {
- int poll_res = poll_event_interruptible(
- CDS_DRIVE_NOT_READY !=
- (ret = cdo->drive_status(cdi, CDSL_CURRENT)),
- 500);
- if (poll_res == -ERESTARTSYS)
- return poll_res;
+ cd_dbg(CD_OPEN, "the drive is not ready...\n");
+ return -ENOMEDIUM;
}
- if (ret != CDS_DISC_OK)
+ if (ret != CDS_DISC_OK) {
+ cd_dbg(CD_OPEN, "drive returned status %i...\n", ret);
return -ENOMEDIUM;
+ }
}
cdrom_count_tracks(cdi, tracks);
if (tracks->error == CDS_NO_DISC) {
@@ -2351,6 +2321,51 @@ static int cdrom_ioctl_closetray(struct cdrom_device_info *cdi)
return cdi->ops->tray_move(cdi, 0);
}

+int cdrom_autoclose(struct cdrom_device_info *cdi)
+{
+ const struct cdrom_device_ops *cdo = cdi->ops;
+ int ret;
+
+ cd_dbg(CD_OPEN, "entering cdrom_autoclose\n");
+ if (!cdo->drive_status)
+ return -ENXIO;
+
+ ret = cdo->drive_status(cdi, CDSL_CURRENT);
+ cd_dbg(CD_OPEN, "drive_status=%d\n", ret);
+
+ if (ret == CDS_TRAY_OPEN)
+ if(CDROM_CAN(CDC_CLOSE_TRAY)) {
+ if (!(cdi->options & CDO_AUTO_CLOSE))
+ return -ENOMEDIUM;
+ cd_dbg(CD_OPEN, "trying to close the tray...\n");
+ ret = cdrom_tray_close(cdi);
+ if (ret == -ERESTARTSYS)
+ return ret;
+ if (ret) {
+ cd_dbg(CD_OPEN, "bummer. tried to close the tray but failed.\n");
+ return -ENOMEDIUM;
+ }
+ ret = cdo->drive_status(cdi, CDSL_CURRENT);
+ } else {
+ cd_dbg(CD_OPEN, "bummer. this drive can't close the tray.\n");
+ return -ENOMEDIUM;
+ }
+ if (ret == CDS_DRIVE_NOT_READY) {
+ int poll_res;
+
+ cd_dbg(CD_OPEN, "waiting for drive to become ready...\n");
+ poll_res = poll_event_interruptible(CDS_DRIVE_NOT_READY !=
+ (ret = cdo->drive_status(cdi, CDSL_CURRENT)), 50);
+ if (poll_res == -ERESTARTSYS)
+ return poll_res;
+ }
+ if (ret != CDS_DISC_OK)
+ return -ENOMEDIUM;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cdrom_autoclose);
+
static int cdrom_ioctl_eject_sw(struct cdrom_device_info *cdi,
unsigned long arg)
{
diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
index 528271c60018..ea0415ba9f9d 100644
--- a/include/linux/cdrom.h
+++ b/include/linux/cdrom.h
@@ -126,6 +126,7 @@ extern void init_cdrom_command(struct packet_command *cgc,
void *buffer, int len, int type);
extern int cdrom_dummy_generic_packet(struct cdrom_device_info *cdi,
struct packet_command *cgc);
+int cdrom_autoclose(struct cdrom_device_info *cdi);

/* The SCSI spec says there could be 256 slots. */
#define CDROM_MAX_SLOTS 256
--
2.23.0