[RFC 6/6] drm/amdgpu: Drop concurrent GPU reset protection for device

[Andrey Grodzovsky]

Since now all GPU resets are serialzied there is no need for this.

This patch also reverts 'drm/amdgpu: race issue when jobs on 2 ring timeout'

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 89 ++--------------------
 1 file changed, 7 insertions(+), 82 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index d2701e4d0622..311e0b9e1e4f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4763,11 +4763,10 @@ int amdgpu_do_asic_reset(struct list_head *device_list_handle,
 	return r;
 }
 
-static bool amdgpu_device_lock_adev(struct amdgpu_device *adev,
+static void amdgpu_device_lock_adev(struct amdgpu_device *adev,
 				struct amdgpu_hive_info *hive)
 {
-	if (atomic_cmpxchg(&adev->in_gpu_reset, 0, 1) != 0)
-		return false;
+	atomic_set(&adev->in_gpu_reset, 1);
 
 	if (hive) {
 		down_write_nest_lock(&adev->reset_sem, &hive->hive_lock);
@@ -4786,8 +4785,6 @@ static bool amdgpu_device_lock_adev(struct amdgpu_device *adev,
 		adev->mp1_state = PP_MP1_STATE_NONE;
 		break;
 	}
-
-	return true;
 }
 
 static void amdgpu_device_unlock_adev(struct amdgpu_device *adev)
@@ -4798,46 +4795,6 @@ static void amdgpu_device_unlock_adev(struct amdgpu_device *adev)
 	up_write(&adev->reset_sem);
 }
 
-/*
- * to lockup a list of amdgpu devices in a hive safely, if not a hive
- * with multiple nodes, it will be similar as amdgpu_device_lock_adev.
- *
- * unlock won't require roll back.
- */
-static int amdgpu_device_lock_hive_adev(struct amdgpu_device *adev, struct amdgpu_hive_info *hive)
-{
-	struct amdgpu_device *tmp_adev = NULL;
-
-	if (adev->gmc.xgmi.num_physical_nodes > 1) {
-		if (!hive) {
-			dev_err(adev->dev, "Hive is NULL while device has multiple xgmi nodes");
-			return -ENODEV;
-		}
-		list_for_each_entry(tmp_adev, &hive->device_list, gmc.xgmi.head) {
-			if (!amdgpu_device_lock_adev(tmp_adev, hive))
-				goto roll_back;
-		}
-	} else if (!amdgpu_device_lock_adev(adev, hive))
-		return -EAGAIN;
-
-	return 0;
-roll_back:
-	if (!list_is_first(&tmp_adev->gmc.xgmi.head, &hive->device_list)) {
-		/*
-		 * if the lockup iteration break in the middle of a hive,
-		 * it may means there may has a race issue,
-		 * or a hive device locked up independently.
-		 * we may be in trouble and may not, so will try to roll back
-		 * the lock and give out a warnning.
-		 */
-		dev_warn(tmp_adev->dev, "Hive lock iteration broke in the middle. Rolling back to unlock");
-		list_for_each_entry_continue_reverse(tmp_adev, &hive->device_list, gmc.xgmi.head) {
-			amdgpu_device_unlock_adev(tmp_adev);
-		}
-	}
-	return -EAGAIN;
-}
-
 static void amdgpu_device_resume_display_audio(struct amdgpu_device *adev)
 {
 	struct pci_dev *p = NULL;
@@ -5023,22 +4980,6 @@ int amdgpu_device_gpu_recover_imp(struct amdgpu_device *adev,
 	reset_context.hive = hive;
 	clear_bit(AMDGPU_NEED_FULL_RESET, &reset_context.flags);
 
-	/*
-	 * lock the device before we try to operate the linked list
-	 * if didn't get the device lock, don't touch the linked list since
-	 * others may iterating it.
-	 */
-	r = amdgpu_device_lock_hive_adev(adev, hive);
-	if (r) {
-		dev_info(adev->dev, "Bailing on TDR for s_job:%llx, as another already in progress",
-					job ? job->base.id : -1);
-
-		/* even we skipped this reset, still need to set the job to guilty */
-		if (job && job->vm)
-			drm_sched_increase_karma(&job->base);
-		goto skip_recovery;
-	}
-
 	/*
 	 * Build list of devices to reset.
 	 * In case we are in XGMI hive mode, resort the device list
@@ -5058,6 +4999,9 @@ int amdgpu_device_gpu_recover_imp(struct amdgpu_device *adev,
 
 	/* block all schedulers and reset given job's ring */
 	list_for_each_entry(tmp_adev, device_list_handle, reset_list) {
+
+		amdgpu_device_lock_adev(tmp_adev, hive);
+
 		/*
 		 * Try to put the audio codec into suspend state
 		 * before gpu reset started.
@@ -5208,13 +5152,12 @@ int amdgpu_device_gpu_recover_imp(struct amdgpu_device *adev,
 		amdgpu_device_unlock_adev(tmp_adev);
 	}
 
-skip_recovery:
 	if (hive) {
 		mutex_unlock(&hive->hive_lock);
 		amdgpu_put_xgmi_hive(hive);
 	}
 
-	if (r && r != -EAGAIN)
+	if (r)
 		dev_info(adev->dev, "GPU reset end with ret = %d\n", r);
 	return r;
 }
@@ -5437,20 +5380,6 @@ int amdgpu_device_baco_exit(struct drm_device *dev)
 	return 0;
 }
 
-static void amdgpu_cancel_all_tdr(struct amdgpu_device *adev)
-{
-	int i;
-
-	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
-		struct amdgpu_ring *ring = adev->rings[i];
-
-		if (!ring || !ring->sched.thread)
-			continue;
-
-		cancel_delayed_work_sync(&ring->sched.work_tdr);
-	}
-}
-
 /**
  * amdgpu_pci_error_detected - Called when a PCI error is detected.
  * @pdev: PCI device struct
@@ -5481,14 +5410,10 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta
 	/* Fatal error, prepare for slot reset */
 	case pci_channel_io_frozen:
 		/*
-		 * Cancel and wait for all TDRs in progress if failing to
-		 * set  adev->in_gpu_reset in amdgpu_device_lock_adev
-		 *
 		 * Locking adev->reset_sem will prevent any external access
 		 * to GPU during PCI error recovery
 		 */
-		while (!amdgpu_device_lock_adev(adev, NULL))
-			amdgpu_cancel_all_tdr(adev);
+		amdgpu_device_lock_adev(adev, NULL);
 
 		/*
 		 * Block any work scheduling as we do for regular GPU reset
-- 
2.25.1