drm/i915/selftests: Lock the drm_mm while modifying

Remember to lock the drm_mm as we modify it, lest it be modified in the
background by retire/free workers!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190703091726.11690-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
index a1f0b23..9b05bef 100644 (file)
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
@@ -414,7 +414,9 @@ static int igt_mmap_offset_exhaustion(void *arg)
        drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
                resv.start = hole_start;
                resv.size = hole_end - hole_start - 1; /* PAGE_SIZE units */
+               mutex_lock(&i915->drm.struct_mutex);
                err = drm_mm_reserve_node(mm, &resv);
+               mutex_unlock(&i915->drm.struct_mutex);
                if (err) {
                        pr_err("Failed to trim VMA manager, err=%d\n", err);
                        goto out_park;
@@ -478,7 +480,9 @@ static int igt_mmap_offset_exhaustion(void *arg)
        }
 
 out:
+       mutex_lock(&i915->drm.struct_mutex);
        drm_mm_remove_node(&resv);
+       mutex_unlock(&i915->drm.struct_mutex);
 out_park:
        restore_retire_worker(i915);
        return err;