drm/xe/userptr: restore invalidation list on error

On error restore anything still on the pin_list back to the invalidation
list on error. For the actual pin, so long as the vma is tracked on
either list it should get picked up on the next pin, however it looks
possible for the vma to get nuked but still be present on this per vm
pin_list leading to corruption. An alternative might be then to instead
just remove the link when destroying the vma.

v2:
 - Also add some asserts.
 - Keep the overzealous locking so that we are consistent with the docs;
   updating the docs and related bits will be done as a follow up.

Fixes: ed2bdf3b264d ("drm/xe/vm: Subclass userptr vmas")
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: <stable@vger.kernel.org> # v6.8+
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250221143840.167150-4-matthew.auld@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
(cherry picked from commit 4e37e928928b730de9aa9a2f5dc853feeebc1742)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 690330352d4cd115b5c8409f6d3ba674c8ec73db..47f7d8f2094b63a5563371b8e9bcba5ae7cf6f35 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -666,15 +666,16 @@ int xe_vm_userptr_pin(struct xe_vm *vm)
 
        /* Collect invalidated userptrs */
        spin_lock(&vm->userptr.invalidated_lock);
+       xe_assert(vm->xe, list_empty(&vm->userptr.repin_list));
        list_for_each_entry_safe(uvma, next, &vm->userptr.invalidated,
                                 userptr.invalidate_link) {
                list_del_init(&uvma->userptr.invalidate_link);
-               list_move_tail(&uvma->userptr.repin_link,
-                              &vm->userptr.repin_list);
+               list_add_tail(&uvma->userptr.repin_link,
+                             &vm->userptr.repin_list);
        }
        spin_unlock(&vm->userptr.invalidated_lock);
 
-       /* Pin and move to temporary list */
+       /* Pin and move to bind list */
        list_for_each_entry_safe(uvma, next, &vm->userptr.repin_list,
                                 userptr.repin_link) {
                err = xe_vma_userptr_pin_pages(uvma);
@@ -690,10 +691,10 @@ int xe_vm_userptr_pin(struct xe_vm *vm)
                        err = xe_vm_invalidate_vma(&uvma->vma);
                        xe_vm_unlock(vm);
                        if (err)
-                               return err;
+                               break;
                } else {
-                       if (err < 0)
-                               return err;
+                       if (err)
+                               break;
 
                        list_del_init(&uvma->userptr.repin_link);
                        list_move_tail(&uvma->vma.combined_links.rebind,
@@ -701,7 +702,19 @@ int xe_vm_userptr_pin(struct xe_vm *vm)
                }
        }
 
-       return 0;
+       if (err) {
+               down_write(&vm->userptr.notifier_lock);
+               spin_lock(&vm->userptr.invalidated_lock);
+               list_for_each_entry_safe(uvma, next, &vm->userptr.repin_list,
+                                        userptr.repin_link) {
+                       list_del_init(&uvma->userptr.repin_link);
+                       list_move_tail(&uvma->userptr.invalidate_link,
+                                      &vm->userptr.invalidated);
+               }
+               spin_unlock(&vm->userptr.invalidated_lock);
+               up_write(&vm->userptr.notifier_lock);
+       }
+       return err;
 }
 
 /**
@@ -1066,6 +1079,7 @@ static void xe_vma_destroy(struct xe_vma *vma, struct dma_fence *fence)
                xe_assert(vm->xe, vma->gpuva.flags & XE_VMA_DESTROYED);
 
                spin_lock(&vm->userptr.invalidated_lock);
+               xe_assert(vm->xe, list_empty(&to_userptr_vma(vma)->userptr.repin_link));
                list_del(&to_userptr_vma(vma)->userptr.invalidate_link);
                spin_unlock(&vm->userptr.invalidated_lock);
        } else if (!xe_vma_is_null(vma)) {