[PATCH v2] usb: f_mass_storage: forbid async queue when shutdown happen

[yuan linyu <yuanlinyu@xxxxxxxxxxx>]

When write UDC to empty and unbind gadget driver from gadget device, it is
possible that there are many queue failures for mass storage function.

The root cause is mass storage main thread alaways try to queue request to
receive a command from host if running flag is on, on platform like dwc3,
if pull down called, it will not queue request again and return
-ESHUTDOWN, but it not affect running flag of mass storage function.

Check return code from mass storage function and clear running flag if it
is -ESHUTDOWN, also indicate start in/out transfer failure to break loops.

Signed-off-by: yuan linyu <yuanlinyu@xxxxxxxxxxx>
---
v2: fix comments, only change coding style, no function change
v1: follow Alan suggestion, only limit change in f_mass_storage
    https://lore.kernel.org/linux-usb/20240122105138.3759477-1-yuanlinyu@xxxxxxxxxxx/
RFC: https://lore.kernel.org/linux-usb/5f4c9d8b6e0e4e73a5b3b1540a500b6a@xxxxxxxxxxx/T/#t

 drivers/usb/gadget/function/f_mass_storage.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 722a3ab2b337..c265a1f62fc1 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -545,21 +545,37 @@ static int start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
 
 static bool start_in_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
 {
+	int rc;
+
 	if (!fsg_is_set(common))
 		return false;
 	bh->state = BUF_STATE_SENDING;
-	if (start_transfer(common->fsg, common->fsg->bulk_in, bh->inreq))
+	rc = start_transfer(common->fsg, common->fsg->bulk_in, bh->inreq);
+	if (rc) {
 		bh->state = BUF_STATE_EMPTY;
+		if (rc == -ESHUTDOWN) {
+			common->running = 0;
+			return false;
+		}
+	}
 	return true;
 }
 
 static bool start_out_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
 {
+	int rc;
+
 	if (!fsg_is_set(common))
 		return false;
 	bh->state = BUF_STATE_RECEIVING;
-	if (start_transfer(common->fsg, common->fsg->bulk_out, bh->outreq))
+	rc = start_transfer(common->fsg, common->fsg->bulk_out, bh->outreq);
+	if (rc) {
 		bh->state = BUF_STATE_FULL;
+		if (rc == -ESHUTDOWN) {
+			common->running = 0;
+			return false;
+		}
+	}
 	return true;
 }
 
-- 
2.25.1