virt: vbox: Do not use wait_event_interruptible when called from kernel context

Do not use wait_event_interruptible when vbg_hgcm_call() gets called from
kernel-context, such as it being called by the vboxsf filesystem code.

This fixes some filesystem related system calls on shared folders
unexpectedly failing with -EINTR.

Fixes: 0532a1b0 ("virt: vbox: Implement passing requestor info to the host for VirtualBox 6.0.x")
Reported-by: Ludovic Pouzenc <bugreports@pouzenc.fr>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210121150754.147598-1-hdegoede@redhat.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/vboxguest/vboxguest_utils.c

@@ -468,7 +468,7 @@ static int hgcm_cancel_call(struct vbg_dev *gdev, struct vmmdev_hgcm_call *call)
  *               Cancellation fun.
  */
 static int vbg_hgcm_do_call(struct vbg_dev *gdev, struct vmmdev_hgcm_call *call,
-			    u32 timeout_ms, bool *leak_it)
+			    u32 timeout_ms, bool interruptible, bool *leak_it)
 {
 	int rc, cancel_rc, ret;
 	long timeout;
@@ -495,10 +495,15 @@ static int vbg_hgcm_do_call(struct vbg_dev *gdev, struct vmmdev_hgcm_call *call,
 	else
 		timeout = msecs_to_jiffies(timeout_ms);
 
-	timeout = wait_event_interruptible_timeout(
-					gdev->hgcm_wq,
-					hgcm_req_done(gdev, &call->header),
-					timeout);
+	if (interruptible) {
+		timeout = wait_event_interruptible_timeout(gdev->hgcm_wq,
+							   hgcm_req_done(gdev, &call->header),
+							   timeout);
+	} else {
+		timeout = wait_event_timeout(gdev->hgcm_wq,
+					     hgcm_req_done(gdev, &call->header),
+					     timeout);
+	}
 
 	/* timeout > 0 means hgcm_req_done has returned true, so success */
 	if (timeout > 0)
@@ -631,7 +636,8 @@ int vbg_hgcm_call(struct vbg_dev *gdev, u32 requestor, u32 client_id,
 	hgcm_call_init_call(call, client_id, function, parms, parm_count,
 			    bounce_bufs);
 
-	ret = vbg_hgcm_do_call(gdev, call, timeout_ms, &leak_it);
+	ret = vbg_hgcm_do_call(gdev, call, timeout_ms,
+			       requestor & VMMDEV_REQUESTOR_USERMODE, &leak_it);
 	if (ret == 0) {
 		*vbox_status = call->header.result;
 		ret = hgcm_call_copy_back_result(call, parms, parm_count,