[PATCH 02/10] drm/i915/userptr: Make gup errors stickier

Chris Wilson
2016-08-12T10:28:32Z

Keep any error reported by the gup_worker until we are notified that the
arena has changed (via the mmu-notifier). This has the importance of
making two consecutive calls to i915_gem_object_get_pages() reporting
the same error, and curtailing an loop of detecting a fault and requeueing
a gup_worker.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem_userptr.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 57218cca7e05..be54825ef3e8 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -542,8 +542,6 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
}
}
obj->userptr.work = ERR_PTR(ret);
- if (ret)
- __i915_gem_userptr_set_active(obj, false);
}

obj->userptr.workers--;
@@ -628,15 +626,14 @@ i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
* to the vma (discard or cloning) which should prevent the more
* egregious cases from causing harm.
*/
- if (IS_ERR(obj->userptr.work)) {
- /* active flag will have been dropped already by the worker */
- ret = PTR_ERR(obj->userptr.work);
- obj->userptr.work = NULL;
- return ret;
- }
- if (obj->userptr.work)
+
+ if (obj->userptr.work) {
/* active flag should still be held for the pending work */
- return -EAGAIN;
+ if (IS_ERR(obj->userptr.work))
+ return PTR_ERR(obj->userptr.work);
+ else
+ return -EAGAIN;
+ }

/* Let the mmu-notifier know that we have begun and need cancellation */
ret = __i915_gem_userptr_set_active(obj, true);
--
2.8.1