drm/i915: Remove request->uniq

We already assign a unique identifier to every request: seqno. That
someone felt like adding a second one without even mentioning why and
tweaking ABI smells very fishy.

Fixes regression from
commit b3a38998
Author: Nick Hoath <nicholas.hoath@intel.com>
Date:   Thu Feb 19 16:30:47 2015 +0000

    drm/i915: Fix a use after free, and unbalanced refcounting

v2: Rebase
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Nick Hoath <nicholas.hoath@intel.com>
Cc: Thomas Daniel <thomas.daniel@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
[danvet: Fixup because different merge order.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1823,8 +1823,6 @@ struct drm_i915_private {
 		void (*stop_ring)(struct intel_engine_cs *ring);
 	} gt;
 
-	uint32_t request_uniq;
-
 	/*
 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
 	 * will be rejected. Instead look for a better place.
@@ -2094,8 +2092,6 @@ struct drm_i915_gem_request {
 	/** process identifier submitting this request */
 	struct pid *pid;
 
-	uint32_t uniq;
-
 	/**
 	 * The ELSP only accepts two elements at a time, so we queue
 	 * context/tail pairs on a given queue (ring->execlist_queue) until the

drivers/gpu/drm/i915/i915_gem.c

@@ -2532,7 +2532,6 @@ int i915_gem_request_alloc(struct intel_engine_cs *ring,
 	}
 
 	rq->ring = ring;
-	rq->uniq = dev_priv->request_uniq++;
 
 	if (i915.enable_execlists)
 		ret = intel_logical_ring_alloc_request_extras(rq, ctx);

drivers/gpu/drm/i915/i915_trace.h

@@ -505,7 +505,6 @@ DECLARE_EVENT_CLASS(i915_gem_request,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
-			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     ),
 
@@ -514,13 +513,11 @@ DECLARE_EVENT_CLASS(i915_gem_request,
 						i915_gem_request_get_ring(req);
 			   __entry->dev = ring->dev->primary->index;
 			   __entry->ring = ring->id;
-			   __entry->uniq = req ? req->uniq : 0;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   ),
 
-	    TP_printk("dev=%u, ring=%u, uniq=%u, seqno=%u",
-		      __entry->dev, __entry->ring, __entry->uniq,
-		      __entry->seqno)
+	    TP_printk("dev=%u, ring=%u, seqno=%u",
+		      __entry->dev, __entry->ring, __entry->seqno)
 );
 
 DEFINE_EVENT(i915_gem_request, i915_gem_request_add,
@@ -565,7 +562,6 @@ TRACE_EVENT(i915_gem_request_wait_begin,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
-			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     __field(bool, blocking)
 			     ),
@@ -581,14 +577,13 @@ TRACE_EVENT(i915_gem_request_wait_begin,
 						i915_gem_request_get_ring(req);
 			   __entry->dev = ring->dev->primary->index;
 			   __entry->ring = ring->id;
-			   __entry->uniq = req ? req->uniq : 0;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   __entry->blocking =
 				     mutex_is_locked(&ring->dev->struct_mutex);
 			   ),
 
-	    TP_printk("dev=%u, ring=%u, uniq=%u, seqno=%u, blocking=%s",
-		      __entry->dev, __entry->ring, __entry->uniq,
+	    TP_printk("dev=%u, ring=%u, seqno=%u, blocking=%s",
+		      __entry->dev, __entry->ring,
 		      __entry->seqno, __entry->blocking ?  "yes (NB)" : "no")
 );
 

drivers/gpu/drm/i915/intel_lrc.c

@@ -540,7 +540,6 @@ static int execlists_context_queue(struct intel_engine_cs *ring,
 		request->ring = ring;
 		request->ctx = to;
 		kref_init(&request->ref);
-		request->uniq = dev_priv->request_uniq++;
 		i915_gem_context_reference(request->ctx);
 	} else {
 		i915_gem_request_reference(request);