Merge tag 's390-6.0-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fix from Vasily Gorbik:

 - Fix potential hangs in VFIO AP driver

* tag 's390-6.0-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/vfio-ap: bypass unnecessary processing of AP resources

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 6c8c41fac4e1..ee82207b4e60 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -984,6 +984,11 @@ static ssize_t assign_adapter_store(struct device *dev,
 		goto done;
 	}
 
+	if (test_bit_inv(apid, matrix_mdev->matrix.apm)) {
+		ret = count;
+		goto done;
+	}
+
 	set_bit_inv(apid, matrix_mdev->matrix.apm);
 
 	ret = vfio_ap_mdev_validate_masks(matrix_mdev);
@@ -1109,6 +1114,11 @@ static ssize_t unassign_adapter_store(struct device *dev,
 		goto done;
 	}
 
+	if (!test_bit_inv(apid, matrix_mdev->matrix.apm)) {
+		ret = count;
+		goto done;
+	}
+
 	clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
 	vfio_ap_mdev_hot_unplug_adapter(matrix_mdev, apid);
 	ret = count;
@@ -1183,6 +1193,11 @@ static ssize_t assign_domain_store(struct device *dev,
 		goto done;
 	}
 
+	if (test_bit_inv(apqi, matrix_mdev->matrix.aqm)) {
+		ret = count;
+		goto done;
+	}
+
 	set_bit_inv(apqi, matrix_mdev->matrix.aqm);
 
 	ret = vfio_ap_mdev_validate_masks(matrix_mdev);
@@ -1286,6 +1301,11 @@ static ssize_t unassign_domain_store(struct device *dev,
 		goto done;
 	}
 
+	if (!test_bit_inv(apqi, matrix_mdev->matrix.aqm)) {
+		ret = count;
+		goto done;
+	}
+
 	clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
 	vfio_ap_mdev_hot_unplug_domain(matrix_mdev, apqi);
 	ret = count;
@@ -1329,6 +1349,11 @@ static ssize_t assign_control_domain_store(struct device *dev,
 		goto done;
 	}
 
+	if (test_bit_inv(id, matrix_mdev->matrix.adm)) {
+		ret = count;
+		goto done;
+	}
+
 	/* Set the bit in the ADM (bitmask) corresponding to the AP control
 	 * domain number (id). The bits in the mask, from most significant to
 	 * least significant, correspond to IDs 0 up to the one less than the
@@ -1378,6 +1403,11 @@ static ssize_t unassign_control_domain_store(struct device *dev,
 		goto done;
 	}
 
+	if (!test_bit_inv(domid, matrix_mdev->matrix.adm)) {
+		ret = count;
+		goto done;
+	}
+
 	clear_bit_inv(domid, matrix_mdev->matrix.adm);
 
 	if (test_bit_inv(domid, matrix_mdev->shadow_apcb.adm)) {