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

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>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20231107001018.55640-1-marex@denx.de
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 1d17331cb036c256261fcfd63571504670c7ab61..c725aed3f626566b03bd0e3720bbe36250e85594 100644 (file)
--- 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;
 }