Re: [PATCH v4 1/1] s390/vfio-ap: fix circular lockdep when setting/clearing crypto masks

On Wed, 10 Mar 2021 10:05:59 -0500 Tony Krowiak akrowiak@linux.ibm.com wrote:

• ret = vfio_ap_mdev_reset_queues(mdev);
  

• matrix_mdev = mdev_get_drvdata(mdev);
  

Is it guaranteed that matrix_mdev can't be NULL here? If yes, please remind me of the mechanism that ensures this.

• /*
  

•  * If the KVM pointer is in the process of being set, wait until
  

•  * the process has completed.
  

•  */
  

• wait_event_cmd(matrix_mdev->wait_for_kvm,
  

• 	       matrix_mdev->kvm_busy == false,
  

• 	       mutex_unlock(&matrix_dev->lock),
  

• 	       mutex_lock(&matrix_dev->lock));
  

• if (matrix_mdev->kvm)
  

• 	ret = vfio_ap_mdev_reset_queues(mdev);
  

• else
  

• 	ret = -ENODEV;
  

Didn't we agree to make the call to vfio_ap_mdev_reset_queues() unconditional again (for reference please take look at Message-ID: 64afa72c-2d6a-2ca1-e576-34e15fa579ed@linux.ibm.com)?

Regards, Halil