[PATCH 2/4] drm/amdkfd: handle partial migration cpages 0

[Philip Yang]

migrate_vma_setup may return cpages 0, means 0 page can be migrated,
treat this as error case to skip the rest of migration steps, and don't
change prange actual loc, to avoid warning message "VRAM BO missing
during validation".

Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 48 ++++++++++++++----------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 069422337cf7..9b68e3e8f2a1 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -409,20 +409,25 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
 			r, prange->svms, prange->start, prange->last);
 		goto out_free;
 	}
-	if (migrate.cpages != npages) {
-		pr_debug("Partial migration. 0x%lx/0x%llx pages can be migrated\n",
-			 migrate.cpages,
-			 npages);
-	}
 
-	if (migrate.cpages) {
-		r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence,
-					     scratch);
-		migrate_vma_pages(&migrate);
-		svm_migrate_copy_done(adev, mfence);
-		migrate_vma_finalize(&migrate);
+	if (migrate.cpages != npages)
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+			 migrate.cpages, npages);
+	else
+		pr_debug("0x%lx pages migrated\n", migrate.cpages);
+
+	if (!migrate.cpages) {
+		pr_debug("failed collect migrate sys pages [0x%lx 0x%lx]\n",
+			 prange->start, prange->last);
+		r = -ENOMEM;
+		goto out_free;
 	}
 
+	r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence, scratch);
+	migrate_vma_pages(&migrate);
+	svm_migrate_copy_done(adev, mfence);
+	migrate_vma_finalize(&migrate);
+
 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
 	svm_range_free_dma_mappings(prange);
 
@@ -636,19 +641,24 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 		goto out_free;
 	}
 
-	pr_debug("cpages %ld\n", migrate.cpages);
+	if (migrate.cpages != npages)
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+			 migrate.cpages, npages);
+	else
+		pr_debug("0x%lx pages migrated\n", migrate.cpages);
 
-	if (migrate.cpages) {
-		r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
-					    scratch, npages);
-		migrate_vma_pages(&migrate);
-		svm_migrate_copy_done(adev, mfence);
-		migrate_vma_finalize(&migrate);
-	} else {
+	if (!migrate.cpages) {
 		pr_debug("failed collect migrate device pages [0x%lx 0x%lx]\n",
 			 prange->start, prange->last);
+		r = -ENOMEM;
+		goto out_free;
 	}
 
+	r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
+				    scratch, npages);
+	migrate_vma_pages(&migrate);
+	svm_migrate_copy_done(adev, mfence);
+	migrate_vma_finalize(&migrate);
 	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
 
 out_free:
-- 
2.17.1