linux-kernel - [PATCH v3 3/7] cdrom: wait for the tray to close

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Date:   Fri, 25 Oct 2019 13:21:40 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     linux-scsi@...r.kernel.org
Cc:     Michal Suchanek <msuchanek@...e.de>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        "Ewan D. Milne" <emilne@...hat.com>,
        Jonathan Corbet <corbet@....net>, Jens Axboe <axboe@...nel.dk>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        "J. Bruce Fields" <bfields@...hat.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Eric Biggers <ebiggers@...gle.com>,
        Benjamin Coddington <bcodding@...hat.com>,
        Hannes Reinecke <hare@...e.com>,
        Omar Sandoval <osandov@...com>, Ming Lei <ming.lei@...hat.com>,
        Damien Le Moal <damien.lemoal@....com>,
        Bart Van Assche <bvanassche@....org>,
        Tejun Heo <tj@...nel.org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v3 3/7] cdrom: wait for the tray to close

The scsi command to close the 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 shortly or reports an error when it detects the tray is
blocked. At worst the wait can be interrupted by the user.

Also wait for the drive to become ready once the tray closes.

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
v2:
 - check drive_status exists before using it
 - rename tray_close -> cdrom_tray_close
 - also wait for drive to become ready after tray closes
 - do not wait in cdrom_ioctl_closetray
---
 drivers/cdrom/cdrom.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 87db82489bf8..27f4fce22781 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1045,6 +1045,18 @@ 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)
 {
 	int ret;
@@ -1062,7 +1074,9 @@ static 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
@@ -1085,6 +1099,15 @@ static int open_for_common(struct cdrom_device_info *cdi, tracktype *tracks)
 			}
 			cd_dbg(CD_OPEN, "the tray is now closed\n");
 		}
+		/* 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;
+		}
 		if (ret != CDS_DISC_OK)
 			return -ENOMEDIUM;
 	}
-- 
2.23.0