[PATCH 4/8] drm/amdkfd: Fix debug unregister procedure on process termination v2

[Felix Kuehling]

From: Yair Shachar <yair.shachar at amd.com>

Take the dbgmgr lock and unregister before destroying the debug manager.
Do this before destroying the queues.

v2: Correct locking order in kfd_ioctl_dbg_register to ake sure the
process mutex and dbgmgr mutex are always taken in the same order.

Signed-off-by: Yair Shachar <yair.shachar at amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay at gmail.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c |  4 ++--
 drivers/gpu/drm/amd/amdkfd/kfd_process.c | 37 +++++++++++++++++++++++---------
 2 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index a25321f..505d391 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -450,8 +450,8 @@ static int kfd_ioctl_dbg_register(struct file *filep,
 		return -EINVAL;
 	}
 
-	mutex_lock(kfd_get_dbgmgr_mutex());
 	mutex_lock(&p->mutex);
+	mutex_lock(kfd_get_dbgmgr_mutex());
 
 	/*
 	 * make sure that we have pdd, if this the first queue created for
@@ -479,8 +479,8 @@ static int kfd_ioctl_dbg_register(struct file *filep,
 	}
 
 out:
-	mutex_unlock(&p->mutex);
 	mutex_unlock(kfd_get_dbgmgr_mutex());
+	mutex_unlock(&p->mutex);
 
 	return status;
 }
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index b81ad816..db08f8f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -224,17 +224,26 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
 
 	mutex_lock(&p->mutex);
 
+	/* Iterate over all process device data structures and if the
+	 * pdd is in debug mode, we should first force unregistration,
+	 * then we will be able to destroy the queues
+	 */
+	list_for_each_entry(pdd, &p->per_device_data, per_device_list) {
+		struct kfd_dev *dev = pdd->dev;
+
+		mutex_lock(kfd_get_dbgmgr_mutex());
+		if (dev && dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
+			if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
+				kfd_dbgmgr_destroy(dev->dbgmgr);
+				dev->dbgmgr = NULL;
+			}
+		}
+		mutex_unlock(kfd_get_dbgmgr_mutex());
+	}
+
 	kfd_process_dequeue_from_all_devices(p);
 	pqm_uninit(&p->pqm);
 
-	/* Iterate over all process device data structure and check
-	 * if we should delete debug managers
-	 */
-	list_for_each_entry(pdd, &p->per_device_data, per_device_list)
-		if ((pdd->dev->dbgmgr) &&
-				(pdd->dev->dbgmgr->pasid == p->pasid))
-			kfd_dbgmgr_destroy(pdd->dev->dbgmgr);
-
 	mutex_unlock(&p->mutex);
 
 	/*
@@ -463,8 +472,16 @@ void kfd_process_iommu_unbind_callback(struct kfd_dev *dev, unsigned int pasid)
 
 	pr_debug("Unbinding process %d from IOMMU\n", pasid);
 
-	if ((dev->dbgmgr) && (dev->dbgmgr->pasid == p->pasid))
-		kfd_dbgmgr_destroy(dev->dbgmgr);
+	mutex_lock(kfd_get_dbgmgr_mutex());
+
+	if (dev->dbgmgr && dev->dbgmgr->pasid == p->pasid) {
+		if (!kfd_dbgmgr_unregister(dev->dbgmgr, p)) {
+			kfd_dbgmgr_destroy(dev->dbgmgr);
+			dev->dbgmgr = NULL;
+		}
+	}
+
+	mutex_unlock(kfd_get_dbgmgr_mutex());
 
 	pdd = kfd_get_process_device_data(dev, p);
 	if (pdd)
-- 
2.7.4