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From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH 5/5] drm/i915/gem: Silence sparse for RCU protection inside the constructor
Date: Thu, 14 Nov 2019 22:57:36 +0000	[thread overview]
Message-ID: <20191114225736.616885-5-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20191114225736.616885-1-chris@chris-wilson.co.uk>

Inside the constructor, while cloning, we need to replace the
dst->engines. Having forgotten that dst->engines is marked as RCU
protected, we need to add the appropriate annotations to make sparse
happy.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 1284f47303fa..6f1e6181f67a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -2009,7 +2009,8 @@ static int clone_engines(struct i915_gem_context *dst,
 	user_engines = i915_gem_context_user_engines(src);
 	i915_gem_context_unlock_engines(src);
 
-	free_engines(dst->engines);
+	/* Serialised by constructor */
+	free_engines(__context_engines_static(dst));
 	RCU_INIT_POINTER(dst->engines, clone);
 	if (user_engines)
 		i915_gem_context_set_user_engines(dst);
@@ -2044,7 +2045,8 @@ static int clone_sseu(struct i915_gem_context *dst,
 	unsigned long n;
 	int err;
 
-	clone = dst->engines; /* no locking required; sole access */
+	/* no locking required; sole access under constructor*/
+	clone = __context_engines_static(dst);
 	if (e->num_engines != clone->num_engines) {
 		err = -EINVAL;
 		goto unlock;
-- 
2.24.0

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

WARNING: multiple messages have this Message-ID (diff)
From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH 5/5] drm/i915/gem: Silence sparse for RCU protection inside the constructor
Date: Thu, 14 Nov 2019 22:57:36 +0000	[thread overview]
Message-ID: <20191114225736.616885-5-chris@chris-wilson.co.uk> (raw)
Message-ID: <20191114225736.5aEIc6wbv9iCSiok5TBfrhJ2csXawc2plFZA4ZFyQio@z> (raw)
In-Reply-To: <20191114225736.616885-1-chris@chris-wilson.co.uk>

Inside the constructor, while cloning, we need to replace the
dst->engines. Having forgotten that dst->engines is marked as RCU
protected, we need to add the appropriate annotations to make sparse
happy.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 1284f47303fa..6f1e6181f67a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -2009,7 +2009,8 @@ static int clone_engines(struct i915_gem_context *dst,
 	user_engines = i915_gem_context_user_engines(src);
 	i915_gem_context_unlock_engines(src);
 
-	free_engines(dst->engines);
+	/* Serialised by constructor */
+	free_engines(__context_engines_static(dst));
 	RCU_INIT_POINTER(dst->engines, clone);
 	if (user_engines)
 		i915_gem_context_set_user_engines(dst);
@@ -2044,7 +2045,8 @@ static int clone_sseu(struct i915_gem_context *dst,
 	unsigned long n;
 	int err;
 
-	clone = dst->engines; /* no locking required; sole access */
+	/* no locking required; sole access under constructor*/
+	clone = __context_engines_static(dst);
 	if (e->num_engines != clone->num_engines) {
 		err = -EINVAL;
 		goto unlock;
-- 
2.24.0

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  parent reply	other threads:[~2019-11-14 22:57 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-14 22:57 [PATCH 1/5] drm/i915/gt: Wait for new requests in intel_gt_retire_requests() Chris Wilson
2019-11-14 22:57 ` [Intel-gfx] " Chris Wilson
2019-11-14 22:57 ` [PATCH 2/5] drm/i915/selftests: Exercise rc6 handling Chris Wilson
2019-11-14 22:57   ` [Intel-gfx] " Chris Wilson
2019-11-14 22:57 ` [PATCH 3/5] drm/i915/selftests: Be explicit in ERR_PTR handling Chris Wilson
2019-11-14 22:57   ` [Intel-gfx] " Chris Wilson
2019-11-15 12:47   ` Tvrtko Ursulin
2019-11-15 12:47     ` [Intel-gfx] " Tvrtko Ursulin
2019-11-15 12:55     ` [PATCH] " Chris Wilson
2019-11-15 12:55       ` [Intel-gfx] " Chris Wilson
2019-11-14 22:57 ` [PATCH 4/5] drm/i915/selftests: Exercise long preemption chains Chris Wilson
2019-11-14 22:57   ` [Intel-gfx] " Chris Wilson
2019-11-15 12:50   ` Tvrtko Ursulin
2019-11-15 12:50     ` [Intel-gfx] " Tvrtko Ursulin
2019-11-14 22:57 ` Chris Wilson [this message]
2019-11-14 22:57   ` [Intel-gfx] [PATCH 5/5] drm/i915/gem: Silence sparse for RCU protection inside the constructor Chris Wilson
2019-11-15 12:55   ` Tvrtko Ursulin
2019-11-15 12:55     ` [Intel-gfx] " Tvrtko Ursulin
2019-11-15  0:12 ` ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/5] drm/i915/gt: Wait for new requests in intel_gt_retire_requests() Patchwork
2019-11-15  0:12   ` [Intel-gfx] " Patchwork
2019-11-15  0:34 ` ✓ Fi.CI.BAT: success " Patchwork
2019-11-15  0:34   ` [Intel-gfx] " Patchwork
2019-11-15 12:45 ` [PATCH 1/5] " Tvrtko Ursulin
2019-11-15 12:45   ` [Intel-gfx] " Tvrtko Ursulin
2019-11-15 12:49   ` Chris Wilson
2019-11-15 12:49     ` [Intel-gfx] " Chris Wilson
2019-11-15 12:56     ` Tvrtko Ursulin
2019-11-15 12:56       ` [Intel-gfx] " Tvrtko Ursulin
2019-11-15 17:18 ` ✗ Fi.CI.BUILD: failure for series starting with [1/5] drm/i915/gt: Wait for new requests in intel_gt_retire_requests() (rev2) Patchwork
2019-11-15 17:18   ` [Intel-gfx] " Patchwork

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