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

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Date:   Fri, 26 Jan 2018 17:58:37 +0100
From:   Michal Suchanek <msuchanek@...e.de>
To:     Jens Axboe <axboe@...nel.dk>, Jonathan Corbet <corbet@....net>,
        Borislav Petkov <bp@...en8.de>, Tim Waugh <tim@...erelk.net>,
        "David S. Miller" <davem@...emloft.net>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Michal Suchanek <msuchanek@...e.de>,
        Kees Cook <keescook@...omium.org>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-ide@...r.kernel.org, linux-scsi@...r.kernel.org
Subject: [PATCH resend 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>
---
v2:
 - check drive_status exists before using it
 - rename tray_close -> cdrom_tray_close
---
 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 89746b3d193f..69e85c902373 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 cdrom_tray_close(struct cdrom_device_info *cdi)
+{
+	int ret;
+
+	ret = cdi->ops->tray_move(cdi, 0);
+	if (ret || !cdi->ops->drive_status)
+		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 = 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
@@ -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 cdrom_tray_close(cdi);
 }
 
 static int cdrom_ioctl_eject_sw(struct cdrom_device_info *cdi,
-- 
2.13.6