linux-kernel - [PATCH 3/6] cdrom: wait for tray to close

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Message-Id: <b12bfb61ef6147ed0c8f0948bcf2e2a1413eee3a.1513263482.git.msuchanek@suse.de>
Date:   Thu, 14 Dec 2017 16:13:52 +0100
From:   Michal Suchanek <msuchanek@...e.de>
To:     Jens Axboe <axboe@...nel.dk>, linux-kernel@...r.kernel.org
Cc:     Michal Suchanek <msuchanek@...e.de>
Subject: [PATCH 3/6] cdrom: wait for tray to close

The scsi command to close tray only starts the motor and does not wait
for the tray to close. Wait until the state chages from TRAY_OPEN so
users do not race with the tray closing.

This looks like inifinte wait but unless the drive is broken it either
closes the tray within a few seconds or reports an error when it detects
the tray is blocked. At worst the wait can be interrupted by user.

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
 drivers/cdrom/cdrom.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index e976d3d0180d..040d3d466cd7 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -281,7 +281,9 @@
 #include <linux/fcntl.h>
 #include <linux/blkdev.h>
 #include <linux/times.h>
+#include <linux/delay.h>
 #include <linux/uaccess.h>
+#include <linux/sched/signal.h>
 #include <scsi/scsi_request.h>
 
 /* used to tell the module to turn on full debugging messages */
@@ -1030,6 +1032,18 @@ static void cdrom_count_tracks(struct cdrom_device_info *cdi, tracktype *tracks)
 	       tracks->cdi, tracks->xa);
 }
 
+static int tray_close(struct cdrom_device_info *cdi)
+{
+	int ret;
+
+	ret = cdi->ops->tray_move(cdi, 0);
+	if (ret)
+		return ret;
+
+	return poll_event_interruptible(CDS_TRAY_OPEN !=
+			cdi->ops->drive_status(cdi, CDSL_CURRENT), 500);
+}
+
 static
 int open_for_common(struct cdrom_device_info *cdi, tracktype *tracks)
 {
@@ -1048,7 +1062,9 @@ int open_for_common(struct cdrom_device_info *cdi, tracktype *tracks)
 			if (CDROM_CAN(CDC_CLOSE_TRAY) &&
 			    cdi->options & CDO_AUTO_CLOSE) {
 				cd_dbg(CD_OPEN, "trying to close the tray\n");
-				ret = cdo->tray_move(cdi, 0);
+				ret = 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
@@ -2312,7 +2328,8 @@ static int cdrom_ioctl_closetray(struct cdrom_device_info *cdi)
 
 	if (!CDROM_CAN(CDC_CLOSE_TRAY))
 		return -ENOSYS;
-	return cdi->ops->tray_move(cdi, 0);
+
+	return tray_close(cdi);
 }
 
 static int cdrom_ioctl_eject_sw(struct cdrom_device_info *cdi,
-- 
2.13.6