drm/i915: Onion unwind for intel_init_ring_common()

Rather than call intel_engine_cleanup() with a partially constructed
engine, unwind the error during intel_init_ring_common().

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170403113426.25707-2-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

1 files changed, 36 insertions, 41 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 5e7634c00cbd..c98acc27279a 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1259,6 +1259,8 @@ static int init_phys_status_page(struct intel_engine_cs *engine)
 {
         struct drm_i915_private *dev_priv = engine->i915;
 
+        GEM_BUG_ON(engine->id != RCS);
+
         dev_priv->status_page_dmah =
                 drm_pci_alloc(&dev_priv->drm, PAGE_SIZE, PAGE_SIZE);
         if (!dev_priv->status_page_dmah)
@@ -1481,76 +1483,69 @@ static void intel_ring_context_unpin(struct intel_engine_cs *engine,
 static int intel_init_ring_buffer(struct intel_engine_cs *engine)
 {
         struct intel_ring *ring;
-        int ret;
-
-        WARN_ON(engine->buffer);
+        int err;
 
         intel_engine_setup_common(engine);
 
-        ret = intel_engine_init_common(engine);
-        if (ret)
-                goto error;
+        err = intel_engine_init_common(engine);
+        if (err)
+                goto err;
 
-        if (HWS_NEEDS_PHYSICAL(engine->i915)) {
-                WARN_ON(engine->id != RCS);
-                ret = init_phys_status_page(engine);
-                if (ret)
-                        goto error;
-        } else {
-                ret = init_status_page(engine);
-                if (ret)
-                        goto error;
-        }
+        if (HWS_NEEDS_PHYSICAL(engine->i915))
+                err = init_phys_status_page(engine);
+        else
+                err = init_status_page(engine);
+        if (err)
+                goto err;
 
         ring = intel_engine_create_ring(engine, 32 * PAGE_SIZE);
         if (IS_ERR(ring)) {
-                ret = PTR_ERR(ring);
-                goto error;
+                err = PTR_ERR(ring);
+                goto err_hws;
         }
 
         /* Ring wraparound at offset 0 sometimes hangs. No idea why. */
-        ret = intel_ring_pin(ring, engine->i915, I915_GTT_PAGE_SIZE);
-        if (ret) {
-                intel_ring_free(ring);
-                goto error;
-        }
+        err = intel_ring_pin(ring, engine->i915, I915_GTT_PAGE_SIZE);
+        if (err)
+                goto err_ring;
+
+        GEM_BUG_ON(engine->buffer);
         engine->buffer = ring;
 
         return 0;
 
-error:
-        intel_engine_cleanup(engine);
-        return ret;
+err_ring:
+        intel_ring_free(ring);
+err_hws:
+        if (HWS_NEEDS_PHYSICAL(engine->i915))
+                cleanup_phys_status_page(engine);
+        else
+                cleanup_status_page(engine);
+err:
+        intel_engine_cleanup_common(engine);
+        return err;
 }
 
 void intel_engine_cleanup(struct intel_engine_cs *engine)
 {
-        struct drm_i915_private *dev_priv;
-
-        dev_priv = engine->i915;
+        struct drm_i915_private *dev_priv = engine->i915;
 
-        if (engine->buffer) {
-                WARN_ON(INTEL_GEN(dev_priv) > 2 &&
-                        (I915_READ_MODE(engine) & MODE_IDLE) == 0);
+        WARN_ON(INTEL_GEN(dev_priv) > 2 &&
+                (I915_READ_MODE(engine) & MODE_IDLE) == 0);
 
-                intel_ring_unpin(engine->buffer);
-                intel_ring_free(engine->buffer);
-                engine->buffer = NULL;
-        }
+        intel_ring_unpin(engine->buffer);
+        intel_ring_free(engine->buffer);
 
         if (engine->cleanup)
                 engine->cleanup(engine);
 
-        if (HWS_NEEDS_PHYSICAL(dev_priv)) {
-                WARN_ON(engine->id != RCS);
+        if (HWS_NEEDS_PHYSICAL(dev_priv))
                 cleanup_phys_status_page(engine);
-        } else {
+        else
                 cleanup_status_page(engine);
-        }
 
         intel_engine_cleanup_common(engine);
 
-        engine->i915 = NULL;
         dev_priv->engine[engine->id] = NULL;
         kfree(engine);
 }