[PATCH] drm/xe: Add more document to xe_vm::lock

[Oak Zeng]

More document is added to xe_vm::lock to describe what is protected
by this lock.

Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Signed-off-by: Oak Zeng <oak.zeng at intel.com>
---
 drivers/gpu/drm/xe/xe_vm_types.h | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index ce1a63a5e3e7..5597d8072046 100644
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -161,7 +161,18 @@ struct xe_vm {
 
 	/**
 	 * @lock: outer most lock, protects objects of anything attached to this
-	 * VM
+	 * VM, more specifically:
+	 * 1) vm::rebind_list
+	 * 2) vm::flags, only XE_VM_FLA_BANNED bit
+	 * 3) vma::tile_present
+	 * 4) userptr::repin_list
+	 * 5) userptr::invalidated list
+	 * 6) vm::preempt::exec_queue
+	 * 7) drm_gpuvm::rb list and tree
+	 * 8) vm::size
+	 * 9) vm::q[]->last_fence, only if q->flags' EXEC_QUEUE_FLAG_VM is set,
+	 *    see xe_exec_queue_last_fence_lockdep_assert
+	 * 10) a contested list during vm close. see xe_vm_close_and_put
 	 */
 	struct rw_semaphore lock;
 	/**
-- 
2.25.1