Merge tag 'vfio-v4.1-rc3' of git://github.com/awilliam/linux-vfio

Pull vfio fixes from Alex Williamson:
 "Fix some undesirable behavior with the vfio device request interface:

   - increase verbosity of device request channel (Alex Williamson)

   - fix runaway interruptible timeout (Alex Williamson)"

* tag 'vfio-v4.1-rc3' of git://github.com/awilliam/linux-vfio:
  vfio: Fix runaway interruptible timeout
  vfio-pci: Log device requests more verbosely

2 files changed, 25 insertions, 4 deletions

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 69fab0fd15ae..e9851add6f4e 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -907,8 +907,14 @@ static void vfio_pci_request(void *device_data, unsigned int count)
 	mutex_lock(&vdev->igate);
 
 	if (vdev->req_trigger) {
-		dev_dbg(&vdev->pdev->dev, "Requesting device from user\n");
+		if (!(count % 10))
+			dev_notice_ratelimited(&vdev->pdev->dev,
+				"Relaying device request to user (#%u)\n",
+				count);
 		eventfd_signal(vdev->req_trigger, 1);
+	} else if (count == 0) {
+		dev_warn(&vdev->pdev->dev,
+			"No device request channel registered, blocked until released by user\n");
 	}
 
 	mutex_unlock(&vdev->igate);
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 0d336625ac71..e1278fe04b1e 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -710,6 +710,8 @@ void *vfio_del_group_dev(struct device *dev)
 	void *device_data = device->device_data;
 	struct vfio_unbound_dev *unbound;
 	unsigned int i = 0;
+	long ret;
+	bool interrupted = false;
 
 	/*
 	 * The group exists so long as we have a device reference.  Get
@@ -755,9 +757,22 @@ void *vfio_del_group_dev(struct device *dev)
 
 		vfio_device_put(device);
 
-	} while (wait_event_interruptible_timeout(vfio.release_q,
-						  !vfio_dev_present(group, dev),
-						  HZ * 10) <= 0);
+		if (interrupted) {
+			ret = wait_event_timeout(vfio.release_q,
+					!vfio_dev_present(group, dev), HZ * 10);
+		} else {
+			ret = wait_event_interruptible_timeout(vfio.release_q,
+					!vfio_dev_present(group, dev), HZ * 10);
+			if (ret == -ERESTARTSYS) {
+				interrupted = true;
+				dev_warn(dev,
+					 "Device is currently in use, task"
+					 " \"%s\" (%d) "
+					 "blocked until device is released",
+					 current->comm, task_pid_nr(current));
+			}
+		}
+	} while (ret <= 0);
 
 	vfio_group_put(group);