[PATCH] usb: gadget: f_mass_storage: Stop ums on START-STOP UNIT SCSI command

[Marek Vasut <marex@denx.de>]

Exit the UMS handler loop in case START-STOP UNIT SCSI command is
received. This is sent e.g. by the util-linux eject(1) command and
indicates to the device that it is supposed to spin down the media
and enter low power state.

This effectively adds support for exitting the 'ums' command from
host using 'eject /dev/sdN' that is on par with 'dfu-util -e' .

Signed-off-by: Marek Vasut <marex@denx.de>
---
Cc: Lukasz Majewski <lukma@denx.de>
Cc: Mattijs Korpershoek <mkorpershoek@baylibre.com>
---
 drivers/usb/gadget/f_mass_storage.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 1d17331cb03..c725aed3f62 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -327,6 +327,7 @@ struct fsg_common {
 	unsigned int		short_packet_received:1;
 	unsigned int		bad_lun_okay:1;
 	unsigned int		running:1;
+	unsigned int		eject:1;
 
 	int			thread_wakeup_needed;
 	struct completion	thread_notifier;
@@ -669,6 +670,10 @@ static int sleep_thread(struct fsg_common *common)
 		}
 
 		if (k == 10) {
+			/* Handle START-STOP UNIT */
+			if (common->eject)
+				return -EPIPE;
+
 			/* Handle CTRL+C */
 			if (ctrlc())
 				return -EPIPE;
@@ -1325,6 +1330,8 @@ static int do_start_stop(struct fsg_common *common)
 		return -EINVAL;
 	}
 
+	common->eject = 1;
+
 	return 0;
 }
 
-- 
2.42.0