drm/i915/dgfx: Grab wakeref at i915_ttm_unmap_virtual

We had already grabbed the rpm wakeref at obj destruction path,
but it also required to grab the wakeref when object moves.
When i915_gem_object_release_mmap_offset() gets called by
i915_ttm_move_notify(), it will release the mmap offset without
grabbing the wakeref. We want to avoid that therefore,
grab the wakeref at i915_ttm_unmap_virtual() accordingly.

While doing that also changed the lmem_userfault_lock from
mutex to spinlock, as spinlock widely used for list.

Also changed if (obj->userfault_count) to
GEM_BUG_ON(!obj->userfault_count).

v2:
- Removed lmem_userfault_{list,lock} from intel_gt. [Matt Auld]

Fixes: ad74457a6b5a ("drm/i915/dgfx: Release mmap on rpm suspend")
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221027092242.1476080-3-anshuman.gupta@intel.com

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 6e7f5b38eb32..8b668ee35bd9 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -648,6 +648,6 @@ void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
 
 	init_intel_runtime_pm_wakeref(rpm);
 	INIT_LIST_HEAD(&rpm->lmem_userfault_list);
-	mutex_init(&rpm->lmem_userfault_lock);
+	spin_lock_init(&rpm->lmem_userfault_lock);
 	intel_wakeref_auto_init(&rpm->userfault_wakeref, rpm);
 }