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From:   Dmitry Osipenko <dmitry.osipenko@collabora.com>
To:     David Airlie <airlied@gmail.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
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        Daniel Stone <daniel@fooishbar.org>,
        Tomeu Vizoso <tomeu.vizoso@collabora.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
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        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        kernel@collabora.com, virtualization@lists.linux-foundation.org
Subject: [PATCH v10 09/11] drm/gem: Add drm_gem_pin_unlocked()
Date:   Mon,  9 Jan 2023 00:04:43 +0300
Message-Id: <20230108210445.3948344-10-dmitry.osipenko@collabora.com>
In-Reply-To: <20230108210445.3948344-1-dmitry.osipenko@collabora.com>
References: <20230108210445.3948344-1-dmitry.osipenko@collabora.com>
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Add unlocked variants of drm_gem_un/pin() functions. These new helpers
will take care of GEM dma-reservation locking for DRM drivers.

VirtIO-GPU driver will use these helpers to pin shmem framebuffers,
preventing them from eviction during scanout.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/drm_gem.c | 29 +++++++++++++++++++++++++++++
 include/drm/drm_gem.h     |  3 +++
 2 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index dbb48fc9dff3..0b8d3da985c7 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1167,6 +1167,35 @@ void drm_gem_unpin(struct drm_gem_object *obj)
 		obj->funcs->unpin(obj);
 }
 
+int drm_gem_pin_unlocked(struct drm_gem_object *obj)
+{
+	int ret;
+
+	if (!obj->funcs->pin)
+		return 0;
+
+	ret = dma_resv_lock_interruptible(obj->resv, NULL);
+	if (ret)
+		return ret;
+
+	ret = obj->funcs->pin(obj);
+	dma_resv_unlock(obj->resv);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_pin_unlocked);
+
+void drm_gem_unpin_unlocked(struct drm_gem_object *obj)
+{
+	if (!obj->funcs->unpin)
+		return;
+
+	dma_resv_lock(obj->resv, NULL);
+	obj->funcs->unpin(obj);
+	dma_resv_unlock(obj->resv);
+}
+EXPORT_SYMBOL(drm_gem_unpin_unlocked);
+
 int drm_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map)
 {
 	int ret;
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 8e5c22f25691..6f6d96f79a67 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -493,4 +493,7 @@ unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru,
 
 bool drm_gem_object_evict(struct drm_gem_object *obj);
 
+int drm_gem_pin_unlocked(struct drm_gem_object *obj);
+void drm_gem_unpin_unlocked(struct drm_gem_object *obj);
+
 #endif /* __DRM_GEM_H__ */
-- 
2.38.1