[Intel-gfx] [PATCH 02/12] drm/i915: Wrap i915_active in a simple kreffed struct

[Ruhl, Michael J]

>-----Original Message-----
>From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Chris
>Wilson
>Sent: Tuesday, March 17, 2020 8:27 AM
>To: intel-gfx at lists.freedesktop.org
>Subject: [Intel-gfx] [PATCH 02/12] drm/i915: Wrap i915_active in a simple
>kreffed struct
>
>For conveniences of callers that just want to use an i915_active to
>track a wide array of concurrent timelines, wrap the base i915_active
>struct inside a kref. This i915_active will self-destruct after use.
>
>Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>---
> drivers/gpu/drm/i915/i915_active.c | 53
>++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/i915_active.h |  4 +++
> 2 files changed, 57 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/i915_active.c
>b/drivers/gpu/drm/i915/i915_active.c
>index c4048628188a..535b8161a597 100644
>--- a/drivers/gpu/drm/i915/i915_active.c
>+++ b/drivers/gpu/drm/i915/i915_active.c
>@@ -937,6 +937,59 @@ void i915_active_noop(struct dma_fence *fence,
>struct dma_fence_cb *cb)
> 	active_fence_cb(fence, cb);
> }
>
>+struct auto_active {
>+	struct i915_active base;
>+	struct kref ref;
>+};
>+
>+struct i915_active *i915_active_get(struct i915_active *ref)
>+{
>+	struct auto_active *aa = container_of(ref, typeof(*aa), base);
>+
>+	kref_get(&aa->ref);

Does this need to be kref_get_unless_zero()?

I asked this a couple of days ago, but found that the email for
chris-wilson.co.uk had bounced.  Not sure if you have answered this or not.

Thanks,

Mike

>+	return &aa->base;
>+}
>+
>+static void auto_release(struct kref *ref)
>+{
>+	struct auto_active *aa = container_of(ref, typeof(*aa), ref);
>+
>+	i915_active_fini(&aa->base);
>+	kfree(aa);
>+}
>+
>+void i915_active_put(struct i915_active *ref)
>+{
>+	struct auto_active *aa = container_of(ref, typeof(*aa), base);
>+
>+	kref_put(&aa->ref, auto_release);
>+}
>+
>+static int auto_active(struct i915_active *ref)
>+{
>+	i915_active_get(ref);
>+	return 0;
>+}
>+
>+static void auto_retire(struct i915_active *ref)
>+{
>+	i915_active_put(ref);
>+}
>+
>+struct i915_active *i915_active_create(void)
>+{
>+	struct auto_active *aa;
>+
>+	aa = kmalloc(sizeof(*aa), GFP_KERNEL);
>+	if (!aa)
>+		return NULL;
>+
>+	kref_init(&aa->ref);
>+	i915_active_init(&aa->base, auto_active, auto_retire);
>+
>+	return &aa->base;
>+}
>+
> #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
> #include "selftests/i915_active.c"
> #endif
>diff --git a/drivers/gpu/drm/i915/i915_active.h
>b/drivers/gpu/drm/i915/i915_active.h
>index b3282ae7913c..bffbcf7751a7 100644
>--- a/drivers/gpu/drm/i915/i915_active.h
>+++ b/drivers/gpu/drm/i915/i915_active.h
>@@ -221,4 +221,8 @@ void i915_request_add_active_barriers(struct
>i915_request *rq);
> void i915_active_print(struct i915_active *ref, struct drm_printer *m);
> void i915_active_unlock_wait(struct i915_active *ref);
>
>+struct i915_active *i915_active_create(void);
>+struct i915_active *i915_active_get(struct i915_active *ref);
>+void i915_active_put(struct i915_active *ref);
>+
> #endif /* _I915_ACTIVE_H_ */
>--
>2.20.1
>
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