Revert "drm/i915: use a separate context for gpu relocs"

Since commit c45e788d ("drm/i915/tgl: Suspend pre-parser across GTT
invalidations"), we now disable the advanced preparser on Tigerlake for the
invalidation phase at the start of the batch, we no longer need to emit
the GPU relocations from a second context as they are now flushed inlined.

References: 8a9a9827 ("drm/i915: use a separate context for gpu relocs")
References: c45e788d ("drm/i915/tgl: Suspend pre-parser across GTT invalidations")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191129124846.949100-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

@@ -253,7 +253,6 @@ struct i915_execbuffer {
 		bool has_fence : 1;
 		bool needs_unfenced : 1;
 
-		struct intel_context *ce;
 		struct i915_request *rq;
 		u32 *rq_cmd;
 		unsigned int rq_size;
@@ -886,9 +885,6 @@ static void eb_destroy(const struct i915_execbuffer *eb)
 {
 	GEM_BUG_ON(eb->reloc_cache.rq);
 
-	if (eb->reloc_cache.ce)
-		intel_context_put(eb->reloc_cache.ce);
-
 	if (eb->lut_size > 0)
 		kfree(eb->buckets);
 }
@@ -912,7 +908,6 @@ static void reloc_cache_init(struct reloc_cache *cache,
 	cache->has_fence = cache->gen < 4;
 	cache->needs_unfenced = INTEL_INFO(i915)->unfenced_needs_alignment;
 	cache->node.flags = 0;
-	cache->ce = NULL;
 	cache->rq = NULL;
 	cache->rq_size = 0;
 }
@@ -1182,7 +1177,7 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
 	if (err)
 		goto err_unmap;
 
-	rq = intel_context_create_request(cache->ce);
+	rq = i915_request_create(eb->context);
 	if (IS_ERR(rq)) {
 		err = PTR_ERR(rq);
 		goto err_unpin;
@@ -1253,29 +1248,6 @@ static u32 *reloc_gpu(struct i915_execbuffer *eb,
 		if (!intel_engine_can_store_dword(eb->engine))
 			return ERR_PTR(-ENODEV);
 
-		if (!cache->ce) {
-			struct intel_context *ce;
-
-			/*
-			 * The CS pre-parser can pre-fetch commands across
-			 * memory sync points and starting gen12 it is able to
-			 * pre-fetch across BB_START and BB_END boundaries
-			 * (within the same context). We therefore use a
-			 * separate context gen12+ to guarantee that the reloc
-			 * writes land before the parser gets to the target
-			 * memory location.
-			 */
-			if (cache->gen >= 12)
-				ce = intel_context_create(eb->context->gem_context,
-							  eb->engine);
-			else
-				ce = intel_context_get(eb->context);
-			if (IS_ERR(ce))
-				return ERR_CAST(ce);
-
-			cache->ce = ce;
-		}
-
 		err = __reloc_gpu_alloc(eb, vma, len);
 		if (unlikely(err))
 			return ERR_PTR(err);