Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

Pull SCSI target fixes from Nicholas Bellinger:
 "This includes the bug-fix for a >= v3.8-rc1 regression specific to
  iscsi-target persistent reservation conflict handling (CC'ed to
  stable), and a tcm_vhost patch to drop VIRTIO_RING_F_EVENT_IDX usage
  so that in-flight qemu vhost-scsi-pci device code can detect the
  proper vhost feature bits.

  Also, there are two more tcm_vhost patches still being discussed by
  MST and Asias for v3.9 that will be required for the in-flight qemu
  vhost-scsi-pci device patch to function properly, and that should
  (hopefully) be the last target fixes for this round."

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Fix RESERVATION_CONFLICT status regression for iscsi-target special case
  tcm_vhost: Avoid VIRTIO_RING_F_EVENT_IDX feature bit

drivers/target/target_core_transport.c

@@ -1139,8 +1139,10 @@ target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
 		return ret;
 
 	ret = target_check_reservation(cmd);
-	if (ret)
+	if (ret) {
+		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
 		return ret;
+	}
 
 	ret = dev->transport->parse_cdb(cmd);
 	if (ret)

drivers/vhost/tcm_vhost.c

@@ -60,6 +60,15 @@ enum {
 	VHOST_SCSI_VQ_IO = 2,
 };
 
+/*
+ * VIRTIO_RING_F_EVENT_IDX seems broken. Not sure the bug is in
+ * kernel but disabling it helps.
+ * TODO: debug and remove the workaround.
+ */
+enum {
+	VHOST_SCSI_FEATURES = VHOST_FEATURES & (~VIRTIO_RING_F_EVENT_IDX)
+};
+
 #define VHOST_SCSI_MAX_TARGET	256
 #define VHOST_SCSI_MAX_VQ	128
 
@@ -946,7 +955,7 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)
 
 static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)
 {
-	if (features & ~VHOST_FEATURES)
+	if (features & ~VHOST_SCSI_FEATURES)
 		return -EOPNOTSUPP;
 
 	mutex_lock(&vs->dev.mutex);
@@ -992,7 +1001,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
 			return -EFAULT;
 		return 0;
 	case VHOST_GET_FEATURES:
-		features = VHOST_FEATURES;
+		features = VHOST_SCSI_FEATURES;
 		if (copy_to_user(featurep, &features, sizeof features))
 			return -EFAULT;
 		return 0;