[Intel-gfx] [RFCv3 04/15] drm/i915: factor out alloc_context_idr() and __i915_gem_create_context()

[Zhi Wang]

For flexible GEM context creation, we factor out __i915_gem_create_context
as the core logic of creation a GEM context. After the refactor, it more
likes a context creation service, which is able to create context by
explicit requirement of upper level components.

For the assumptions in original implementation, we keep them in the upper
level wrapper: i915_gem_create_context().

alloc_context_idr() is another function factored out to setup a IDR for
ordinary GEM context. Some context, e.g. GVT context, will not be
manipulated by user space application, so it doesn't need an IDR.

Signed-off-by: Zhi Wang <zhi.a.wang at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 62 ++++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 4be2ce9..38e9fe1 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -235,17 +235,7 @@ __create_hw_context(struct drm_device *dev,
 		ctx->legacy_hw_ctx.rcs_state = obj;
 	}
 
-	/* Default context will never have a file_priv */
-	if (file_priv != NULL) {
-		ret = idr_alloc(&file_priv->context_idr, ctx,
-				DEFAULT_CONTEXT_HANDLE, 0, GFP_KERNEL);
-		if (ret < 0)
-			goto err_out;
-	} else
-		ret = DEFAULT_CONTEXT_HANDLE;
-
 	ctx->file_priv = file_priv;
-	ctx->user_handle = ret;
 	/* NB: Mark all slices as needing a remap so that when the context first
 	 * loads it will restore whatever remap state already exists. If there
 	 * is no remap info, it will be a NOP. */
@@ -260,13 +250,8 @@ err_out:
 	return ERR_PTR(ret);
 }
 
-/**
- * The default context needs to exist per ring that uses contexts. It stores the
- * context state of the GPU for applications that don't utilize HW contexts, as
- * well as an idle case.
- */
 static struct intel_context *
-i915_gem_create_context(struct drm_device *dev,
+__i915_gem_create_context(struct drm_device *dev,
 			struct drm_i915_file_private *file_priv)
 {
 	const bool is_global_default_ctx = file_priv == NULL;
@@ -316,11 +301,54 @@ err_unpin:
 	if (is_global_default_ctx && ctx->legacy_hw_ctx.rcs_state)
 		i915_gem_object_ggtt_unpin(ctx->legacy_hw_ctx.rcs_state);
 err_destroy:
-	idr_remove(&file_priv->context_idr, ctx->user_handle);
 	i915_gem_context_unreference(ctx);
 	return ERR_PTR(ret);
 }
 
+static inline int alloc_context_idr(struct drm_device *dev,
+	struct intel_context *ctx)
+{
+	int ret;
+
+	/* Default context will never have a file_priv */
+	if (ctx->file_priv != NULL) {
+		ret = idr_alloc(&ctx->file_priv->context_idr, ctx,
+				DEFAULT_CONTEXT_HANDLE, 0, GFP_KERNEL);
+		if (ret < 0)
+			return ret;
+	} else {
+		ret = DEFAULT_CONTEXT_HANDLE;
+	}
+
+	ctx->user_handle = ret;
+	return 0;
+}
+
+/**
+ * The default context needs to exist per ring that uses contexts. It stores the
+ * context state of the GPU for applications that don't utilize HW contexts, as
+ * well as an idle case.
+ */
+static struct intel_context *
+i915_gem_create_context(struct drm_device *dev,
+		struct drm_i915_file_private *file_priv)
+{
+	struct intel_context *ctx;
+	int ret;
+
+	ctx = __i915_gem_create_context(dev, file_priv);
+	if (IS_ERR(ctx))
+		return ctx;
+
+	ret = alloc_context_idr(dev, ctx);
+	if (ret < 0) {
+		i915_gem_context_unreference(ctx);
+		return ERR_PTR(ret);
+	}
+
+	return ctx;
+}
+
 static void i915_gem_context_unpin(struct intel_context *ctx,
 				   struct intel_engine_cs *engine)
 {
-- 
1.9.1