From: Lucas Stach <l.stach@pengutronix.de>
Date: Fri, 17 Nov 2017 11:23:17 +0100
Subject: drm/etnaviv: add lockdep annotation for userptr object population
Git-commit: 783c06cb9c9072ff87903cce73317209b3af8568
Patch-mainline: v4.16-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The current userptr page population will defer work to a work item if
needed to avoid ever taking the mmap_sem in the direct call path. With
the more fine-grained locking in etnaviv this isn't needed anymore, so
a future commit will simplify this code.

Add a lockdep annotation to validate the assumption that the mmap_sem
can be taken in the direct call path.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/etnaviv/etnaviv_gem.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -804,6 +804,8 @@ static int etnaviv_gem_userptr_get_pages
 	struct mm_struct *mm;
 	int ret, pinned, npages = etnaviv_obj->base.size >> PAGE_SHIFT;
 
+	might_lock_read(&current->mm->mmap_sem);
+
 	if (etnaviv_obj->userptr.work) {
 		if (IS_ERR(etnaviv_obj->userptr.work)) {
 			ret = PTR_ERR(etnaviv_obj->userptr.work);