[Intel-gfx] [PATCH 45/70] drm/i915: Remove request->uniq

[Chris Wilson]

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 b3a38998f042b862f5ba4d7f2268f3a8dfb4883a
Author: Nick Hoath <nicholas.hoath at 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 at chris-wilson.co.uk>
Cc: Nick Hoath <nicholas.hoath at intel.com>
Cc: Thomas Daniel <thomas.daniel at intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |  4 ----
 drivers/gpu/drm/i915/i915_gem.c   |  1 -
 drivers/gpu/drm/i915/i915_trace.h | 13 ++++---------
 3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 262ebb620112..89839751237c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1843,8 +1843,6 @@ 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.
@@ -2120,8 +2118,6 @@ 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
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c394c0d13eb7..e90894545fa4 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2660,7 +2660,6 @@ 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);
diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index ce8ee9e8bced..6e2eee52aaa2 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -499,7 +499,6 @@ DECLARE_EVENT_CLASS(i915_gem_request,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
-			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     ),
 
@@ -508,13 +507,11 @@ 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,
@@ -559,7 +556,6 @@ 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)
 			     ),
@@ -575,14 +571,13 @@ 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")
 );
 
-- 
2.1.4