drm/i915: Update ring position from request on retiring

When wedged, we do not update the ring->tail as we submit the requests
causing us to leak the ring->space upon cleaning up the wedged driver.
We can just use the value stored in rq->tail, and keep the submission
backend details away from set-wedge.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180307134226.25492-3-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index d437bea..75c8826 100644 (file)
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -358,7 +358,7 @@ static void advance_ring(struct i915_request *request)
                 * is just about to be. Either works, if we miss the last two
                 * noops - they are safe to be replayed on a reset.
                 */
-               tail = READ_ONCE(request->ring->tail);
+               tail = READ_ONCE(request->tail);
        } else {
                tail = request->postfix;
        }

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 1d59952..88eeb64 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1593,6 +1593,7 @@ static noinline int wait_for_space(struct intel_ring *ring, unsigned int bytes)
        if (intel_ring_update_space(ring) >= bytes)
                return 0;
 
+       GEM_BUG_ON(list_empty(&ring->request_list));
        list_for_each_entry(target, &ring->request_list, ring_link) {
                /* Would completion of this request free enough space? */
                if (bytes <= __intel_ring_space(target->postfix,