[Intel-xe] [PATCH 4/4] drm/xe/vm: Fix ASID XA usage

[Thomas Hellström]

xa_alloc_cyclic() returns 1 on successful allocation, if wrapping occurs,
but the code incorrectly treats that as an error. Fix that.
Also, xa_alloc_cyclic() requires xa_init_flags(..., XA_FLAGS_ALLOC), so
fix that, and assuming we don't want a zero ASID, instead of using
XA_FLAGS_ALLOC1, adjust the xa limits at alloc_cyclic time.

Suggested-by: Ohad Sharabi <osharabi at habana.ai>
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/946
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 2 +-
 drivers/gpu/drm/xe/xe_vm.c     | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 8be765adf702..a67aaa15b4ae 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -230,7 +230,7 @@ struct xe_device *xe_device_create(struct pci_dev *pdev,
 	init_waitqueue_head(&xe->ufence_wq);
 
 	drmm_mutex_init(&xe->drm, &xe->usm.lock);
-	xa_init_flags(&xe->usm.asid_to_vm, XA_FLAGS_ALLOC1);
+	xa_init_flags(&xe->usm.asid_to_vm, XA_FLAGS_ALLOC);
 
 	drmm_mutex_init(&xe->drm, &xe->persistent_engines.lock);
 	INIT_LIST_HEAD(&xe->persistent_engines.list);
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index b39c6f43f01f..85b9d6f864ec 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -1994,13 +1994,14 @@ int xe_vm_create_ioctl(struct drm_device *dev, void *data,
 	if (xe->info.has_asid) {
 		mutex_lock(&xe->usm.lock);
 		err = xa_alloc_cyclic(&xe->usm.asid_to_vm, &asid, vm,
-				      XA_LIMIT(0, XE_MAX_ASID - 1),
+				      XA_LIMIT(1, XE_MAX_ASID - 1),
 				      &xe->usm.next_asid, GFP_KERNEL);
 		mutex_unlock(&xe->usm.lock);
-		if (err) {
+		if (err < 0) {
 			xe_vm_close_and_put(vm);
 			return err;
 		}
+		err = 0;
 		vm->usm.asid = asid;
 	}
 
-- 
2.41.0