[PATCH] drm/amdkfd: Change error handling at prange update in svm_range_set_attr

[Xiaogang.Chen <xiaogang.chen@amd.com>]

From: Xiaogang Chen <xiaogang.chen@amd.com>

When register a vm range at svm the added vm range may be split into multiple
subranges and/or existing pranges got spitted. The new pranges need validated
and mapped. This patch changes error handling for pranges that fail updating:

1: free prange resources and remove it from svms if its updating fails as it
will not be used.
2: return -EAGAIN when all pranges at update_list need redo valid/map,
otherwise return no -EAGAIN error to user space to indicate failure. That
removes unnecessary retries.

Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index e32e19196f6b..455cb98bf16a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -3716,8 +3716,19 @@ svm_range_set_attr(struct kfd_process *p, struct mm_struct *mm,
 
 out_unlock_range:
 		mutex_unlock(&prange->migrate_mutex);
-		if (r)
-			ret = r;
+		/* this prange cannot be migraed, valid or map */
+		if (r) {
+			/* free this prange resources, remove it from svms */
+			svm_range_unlink(prange);
+			svm_range_remove_notifier(prange);
+			svm_range_free(prange, false);
+
+			/* ret got update when any r != -EAGAIN;
+			 * return -EAGAIN when all pranges at update_list
+			 * need redo valid/map */
+			if (r != -EAGAIN || !ret)
+				ret = r;
+		}
 	}
 
 	list_for_each_entry(prange, &remap_list, update_list) {
@@ -3729,8 +3740,16 @@ svm_range_set_attr(struct kfd_process *p, struct mm_struct *mm,
 		if (r)
 			pr_debug("failed %d on remap svm range\n", r);
 		mutex_unlock(&prange->migrate_mutex);
-		if (r)
-			ret = r;
+
+		if (r) {
+			/* remove this prange */
+			svm_range_unlink(prange);
+			svm_range_remove_notifier(prange);
+			svm_range_free(prange, false);
+
+			if (r != -EAGAIN || !ret)
+				ret = r;
+		}
 	}
 
 	dynamic_svm_range_dump(svms);
-- 
2.25.1