drm/i915/execlists: Move request unwinding to a separate function

In the future, we will want to unwind requests following a preemption
point. This requires the same steps as for unwinding upon a reset, so
extract the existing code to a separate function for later use.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170928193910.17988-2-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 61cac26a8b05c6865e8fdab2721a0cf14530503a..cbac2fff8e4dd10c13286f26bca564df7e490d6e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -210,6 +210,7 @@
 #define EXECLISTS_REQUEST_SIZE 64 /* bytes */
 
 #define WA_TAIL_DWORDS 2
+#define WA_TAIL_BYTES (sizeof(u32) * WA_TAIL_DWORDS)
 
 static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
                                            struct intel_engine_cs *engine);
@@ -348,6 +349,37 @@ find_priolist:
        return ptr_pack_bits(p, first, 1);
 }
 
+static void unwind_wa_tail(struct drm_i915_gem_request *rq)
+{
+       rq->tail = intel_ring_wrap(rq->ring, rq->wa_tail - WA_TAIL_BYTES);
+       assert_ring_tail_valid(rq->ring, rq->tail);
+}
+
+static void unwind_incomplete_requests(struct intel_engine_cs *engine)
+{
+       struct drm_i915_gem_request *rq, *rn;
+
+       lockdep_assert_held(&engine->timeline->lock);
+
+       list_for_each_entry_safe_reverse(rq, rn,
+                                        &engine->timeline->requests,
+                                        link) {
+               struct i915_priolist *p;
+
+               if (i915_gem_request_completed(rq))
+                       return;
+
+               __i915_gem_request_unsubmit(rq);
+               unwind_wa_tail(rq);
+
+               p = lookup_priolist(engine,
+                                   &rq->priotree,
+                                   rq->priotree.priority);
+               list_add(&rq->priotree.link,
+                        &ptr_mask_bits(p, 1)->requests);
+       }
+}
+
 static inline void
 execlists_context_status_change(struct drm_i915_gem_request *rq,
                                unsigned long status)
@@ -1382,7 +1414,6 @@ static void reset_common_ring(struct intel_engine_cs *engine,
                              struct drm_i915_gem_request *request)
 {
        struct intel_engine_execlists * const execlists = &engine->execlists;
-       struct drm_i915_gem_request *rq, *rn;
        struct intel_context *ce;
        unsigned long flags;
 
@@ -1400,21 +1431,7 @@ static void reset_common_ring(struct intel_engine_cs *engine,
        execlist_cancel_port_requests(execlists);
 
        /* Push back any incomplete requests for replay after the reset. */
-       list_for_each_entry_safe_reverse(rq, rn,
-                                        &engine->timeline->requests, link) {
-               struct i915_priolist *p;
-
-               if (i915_gem_request_completed(rq))
-                       break;
-
-               __i915_gem_request_unsubmit(rq);
-
-               p = lookup_priolist(engine,
-                                   &rq->priotree,
-                                   rq->priotree.priority);
-               list_add(&rq->priotree.link,
-                        &ptr_mask_bits(p, 1)->requests);
-       }
+       unwind_incomplete_requests(engine);
 
        spin_unlock_irqrestore(&engine->timeline->lock, flags);
 
@@ -1451,10 +1468,7 @@ static void reset_common_ring(struct intel_engine_cs *engine,
        intel_ring_update_space(request->ring);
 
        /* Reset WaIdleLiteRestore:bdw,skl as well */
-       request->tail =
-               intel_ring_wrap(request->ring,
-                               request->wa_tail - WA_TAIL_DWORDS*sizeof(u32));
-       assert_ring_tail_valid(request->ring, request->tail);
+       unwind_wa_tail(request);
 }
 
 static int intel_logical_ring_emit_pdps(struct drm_i915_gem_request *req)