drm/i915: Export intel_context_instance()

We want to pass in a intel_context into intel_context_pin() and that
requires us to first be able to lookup the intel_context!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190426163336.15906-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_context.c

@@ -104,7 +104,7 @@ void __intel_context_remove(struct intel_context *ce)
 	spin_unlock(&ctx->hw_contexts_lock);
 }
 
-static struct intel_context *
+struct intel_context *
 intel_context_instance(struct i915_gem_context *ctx,
 		       struct intel_engine_cs *engine)
 {
@@ -112,7 +112,7 @@ intel_context_instance(struct i915_gem_context *ctx,
 
 	ce = intel_context_lookup(ctx, engine);
 	if (likely(ce))
-		return ce;
+		return intel_context_get(ce);
 
 	ce = intel_context_alloc();
 	if (!ce)
@@ -125,7 +125,7 @@ intel_context_instance(struct i915_gem_context *ctx,
 		intel_context_free(ce);
 
 	GEM_BUG_ON(intel_context_lookup(ctx, engine) != pos);
-	return pos;
+	return intel_context_get(pos);
 }
 
 struct intel_context *
@@ -139,30 +139,30 @@ intel_context_pin_lock(struct i915_gem_context *ctx,
 	if (IS_ERR(ce))
 		return ce;
 
-	if (mutex_lock_interruptible(&ce->pin_mutex))
+	if (mutex_lock_interruptible(&ce->pin_mutex)) {
+		intel_context_put(ce);
 		return ERR_PTR(-EINTR);
+	}
 
 	return ce;
 }
 
-struct intel_context *
-intel_context_pin(struct i915_gem_context *ctx,
-		  struct intel_engine_cs *engine)
+void intel_context_pin_unlock(struct intel_context *ce)
+	__releases(ce->pin_mutex)
 {
-	struct intel_context *ce;
-	int err;
-
-	ce = intel_context_instance(ctx, engine);
-	if (IS_ERR(ce))
-		return ce;
+	mutex_unlock(&ce->pin_mutex);
+	intel_context_put(ce);
+}
 
-	if (likely(atomic_inc_not_zero(&ce->pin_count)))
-		return ce;
+int __intel_context_do_pin(struct intel_context *ce)
+{
+	int err;
 
 	if (mutex_lock_interruptible(&ce->pin_mutex))
-		return ERR_PTR(-EINTR);
+		return -EINTR;
 
 	if (likely(!atomic_read(&ce->pin_count))) {
+		struct i915_gem_context *ctx = ce->gem_context;
 		intel_wakeref_t wakeref;
 
 		err = 0;
@@ -172,7 +172,6 @@ intel_context_pin(struct i915_gem_context *ctx,
 			goto err;
 
 		i915_gem_context_get(ctx);
-		GEM_BUG_ON(ce->gem_context != ctx);
 
 		mutex_lock(&ctx->mutex);
 		list_add(&ce->active_link, &ctx->active_engines);
@@ -186,11 +185,11 @@ intel_context_pin(struct i915_gem_context *ctx,
 	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
 
 	mutex_unlock(&ce->pin_mutex);
-	return ce;
+	return 0;
 
 err:
 	mutex_unlock(&ce->pin_mutex);
-	return ERR_PTR(err);
+	return err;
 }
 
 void intel_context_unpin(struct intel_context *ce)

drivers/gpu/drm/i915/gt/intel_context.h

@@ -49,11 +49,7 @@ intel_context_is_pinned(struct intel_context *ce)
 	return atomic_read(&ce->pin_count);
 }
 
-static inline void intel_context_pin_unlock(struct intel_context *ce)
-__releases(ce->pin_mutex)
-{
-	mutex_unlock(&ce->pin_mutex);
-}
+void intel_context_pin_unlock(struct intel_context *ce);
 
 struct intel_context *
 __intel_context_insert(struct i915_gem_context *ctx,
@@ -63,7 +59,18 @@ void
 __intel_context_remove(struct intel_context *ce);
 
 struct intel_context *
-intel_context_pin(struct i915_gem_context *ctx, struct intel_engine_cs *engine);
+intel_context_instance(struct i915_gem_context *ctx,
+		       struct intel_engine_cs *engine);
+
+int __intel_context_do_pin(struct intel_context *ce);
+
+static inline int intel_context_pin(struct intel_context *ce)
+{
+	if (likely(atomic_inc_not_zero(&ce->pin_count)))
+		return 0;
+
+	return __intel_context_do_pin(ce);
+}
 
 static inline void __intel_context_pin(struct intel_context *ce)
 {

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -713,11 +713,17 @@ static int pin_context(struct i915_gem_context *ctx,
 		       struct intel_context **out)
 {
 	struct intel_context *ce;
+	int err;
 
-	ce = intel_context_pin(ctx, engine);
+	ce = intel_context_instance(ctx, engine);
 	if (IS_ERR(ce))
 		return PTR_ERR(ce);
 
+	err = intel_context_pin(ce);
+	intel_context_put(ce);
+	if (err)
+		return err;
+
 	*out = ce;
 	return 0;
 }

drivers/gpu/drm/i915/gt/mock_engine.c

@@ -239,6 +239,7 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 				    int id)
 {
 	struct mock_engine *engine;
+	int err;
 
 	GEM_BUG_ON(id >= I915_NUM_ENGINES);
 
@@ -278,10 +279,15 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 	INIT_LIST_HEAD(&engine->hw_queue);
 
 	engine->base.kernel_context =
-		intel_context_pin(i915->kernel_context, &engine->base);
+		intel_context_instance(i915->kernel_context, &engine->base);
 	if (IS_ERR(engine->base.kernel_context))
 		goto err_breadcrumbs;
 
+	err = intel_context_pin(engine->base.kernel_context);
+	intel_context_put(engine->base.kernel_context);
+	if (err)
+		goto err_breadcrumbs;
+
 	return &engine->base;
 
 err_breadcrumbs:

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -1183,12 +1183,17 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
 		INIT_LIST_HEAD(&s->workload_q_head[i]);
 		s->shadow[i] = ERR_PTR(-EINVAL);
 
-		ce = intel_context_pin(ctx, engine);
+		ce = intel_context_instance(ctx, engine);
 		if (IS_ERR(ce)) {
 			ret = PTR_ERR(ce);
 			goto out_shadow_ctx;
 		}
 
+		ret = intel_context_pin(ce);
+		intel_context_put(ce);
+		if (ret)
+			goto out_shadow_ctx;
+
 		s->shadow[i] = ce;
 	}
 

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -2100,14 +2100,19 @@ static int eb_pin_context(struct i915_execbuffer *eb,
 	if (err)
 		return err;
 
+	ce = intel_context_instance(eb->gem_context, engine);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
 	/*
 	 * Pinning the contexts may generate requests in order to acquire
 	 * GGTT space, so do this first before we reserve a seqno for
 	 * ourselves.
 	 */
-	ce = intel_context_pin(eb->gem_context, engine);
-	if (IS_ERR(ce))
-		return PTR_ERR(ce);
+	err = intel_context_pin(ce);
+	intel_context_put(ce);
+	if (err)
+		return err;
 
 	eb->engine = engine;
 	eb->context = ce;

drivers/gpu/drm/i915/i915_perf.c

@@ -1205,11 +1205,17 @@ static struct intel_context *oa_pin_context(struct drm_i915_private *i915,
 {
 	struct intel_engine_cs *engine = i915->engine[RCS0];
 	struct intel_context *ce;
-	int ret;
+	int err;
 
-	ret = i915_mutex_lock_interruptible(&i915->drm);
-	if (ret)
-		return ERR_PTR(ret);
+	ce = intel_context_instance(ctx, engine);
+	if (IS_ERR(ce))
+		return ce;
+
+	err = i915_mutex_lock_interruptible(&i915->drm);
+	if (err) {
+		intel_context_put(ce);
+		return ERR_PTR(err);
+	}
 
 	/*
 	 * As the ID is the gtt offset of the context's vma we
@@ -1217,10 +1223,11 @@ static struct intel_context *oa_pin_context(struct drm_i915_private *i915,
 	 *
 	 * NB: implied RCS engine...
 	 */
-	ce = intel_context_pin(ctx, engine);
+	err = intel_context_pin(ce);
 	mutex_unlock(&i915->drm.struct_mutex);
-	if (IS_ERR(ce))
-		return ce;
+	intel_context_put(ce);
+	if (err)
+		return ERR_PTR(err);
 
 	i915->perf.oa.pinned_ctx = ce;
 

drivers/gpu/drm/i915/i915_request.c

@@ -785,6 +785,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	struct drm_i915_private *i915 = engine->i915;
 	struct intel_context *ce;
 	struct i915_request *rq;
+	int err;
 
 	/*
 	 * Preempt contexts are reserved for exclusive use to inject a
@@ -798,13 +799,21 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	 * GGTT space, so do this first before we reserve a seqno for
 	 * ourselves.
 	 */
-	ce = intel_context_pin(ctx, engine);
+	ce = intel_context_instance(ctx, engine);
 	if (IS_ERR(ce))
 		return ERR_CAST(ce);
 
+	err = intel_context_pin(ce);
+	if (err) {
+		rq = ERR_PTR(err);
+		goto err_put;
+	}
+
 	rq = i915_request_create(ce);
 	intel_context_unpin(ce);
 
+err_put:
+	intel_context_put(ce);
 	return rq;
 }