drm/i915: Switch back to an array of logical per-engine HW contexts

We switched to a tree of per-engine HW context to accommodate the
introduction of virtual engines. However, we plan to also support
multiple instances of the same engine within the GEM context, defeating
our use of the engine as a key to looking up the HW context. Just
allocate a logical per-engine instance and always use an index into the
ctx->engines[]. Later on, this ctx->engines[] may be replaced by a user
specified map.

v2: Add for_each_gem_engine() helper to iterator within the engines lock
v3: intel_context_create_request() helper
v4: s/unsigned long/unsigned int/ 4 billion engines is quite enough.
v5: Push iterator locking to caller

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190426163336.15906-7-chris@chris-wilson.co.uk

1 files changed, 3 insertions, 12 deletions

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 1a03ebcaf52e..7638a5e5ec9e 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -785,7 +785,6 @@ 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
@@ -799,21 +798,13 @@ 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_instance(ctx, engine);
+	ce = i915_gem_context_get_engine(ctx, engine->id);
 	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:
+	rq = intel_context_create_request(ce);
 	intel_context_put(ce);
+
 	return rq;
 }