[PATCH v4 04/10] cdrom: export autoclose logic as a separate function

From: Michal Suchanek
Date: Thu Nov 21 2019 - 12:14:30 EST


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@xxxxxxx>
---
v2: new patch
v3:
- change IOCTL to export
- fix the logic about reporting cdroms inability to close tray
v4:
- move the autoclose code to the open code, align debug messages with
the open code
---
drivers/cdrom/cdrom.c | 85 ++++++++++++++++++++++++++++++-------------
include/linux/cdrom.h | 1 +
2 files changed, 61 insertions(+), 25 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index b2bc0c8f9a69..38e6db879de0 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1067,6 +1067,56 @@ static int cdrom_tray_close(struct cdrom_device_info *cdi)
return cdrom_wait_for_status_change(cdi, &ret);
}

+int cdrom_autoclose(struct cdrom_device_info *cdi)
+{
+ int ret;
+ const struct cdrom_device_ops *cdo = cdi->ops;
+
+ cd_dbg(CD_OPEN, "entering cdrom_autoclose\n");
+ if (!cdo->drive_status)
+ return -EOPNOTSUPP;
+
+ ret = cdo->drive_status(cdi, CDSL_CURRENT);
+ cd_dbg(CD_OPEN, "drive_status=%d\n", ret);
+
+ if (ret == CDS_TRAY_OPEN) {
+ cd_dbg(CD_OPEN, "the tray is open...\n");
+ 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);
+ if (ret == CDS_NO_DISC)
+ cd_dbg(CD_OPEN, "tray might not contain a medium\n");
+ } 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 = cdrom_wait_for_status_change(cdi, &ret);
+ if (poll_res == -ERESTARTSYS)
+ return poll_res;
+ }
+
+ if (ret != CDS_DISC_OK)
+ return -ENOMEDIUM;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(cdrom_autoclose);
+
static int open_for_common(struct cdrom_device_info *cdi, tracktype *tracks)
{
int ret;
@@ -1080,35 +1130,20 @@ 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");
- 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);
- if (ret == CDS_NO_DISC)
- cd_dbg(CD_OPEN, "tray might not contain a medium\n");
- } else {
- cd_dbg(CD_OPEN, "bummer. this drive can't close the tray.\n");
- return -ENOMEDIUM;
- }
+ return -ENOMEDIUM;
}
if (ret == CDS_DRIVE_NOT_READY) {
- int poll_res;
-
- cd_dbg(CD_OPEN, "waiting for drive to become ready...\n");
- poll_res = cdrom_wait_for_status_change(cdi, &ret);
- 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_NO_DISC) {
+ cd_dbg(CD_OPEN, "tray might not contain a medium...\n");
return -ENOMEDIUM;
+ }
+ 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) {
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