linux-kernel - [PATCH v11 08/10] drm/gem: Add drm_gem_pin

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Message-Id: <20230227060219.904986-9-dmitry.osipenko@collabora.com>
Date:   Mon, 27 Feb 2023 09:02:17 +0300
From:   Dmitry Osipenko <dmitry.osipenko@...labora.com>
To:     David Airlie <airlied@...il.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Gurchetan Singh <gurchetansingh@...omium.org>,
        Chia-I Wu <olvaffe@...il.com>, Daniel Vetter <daniel@...ll.ch>,
        Daniel Almeida <daniel.almeida@...labora.com>,
        Gustavo Padovan <gustavo.padovan@...labora.com>,
        Daniel Stone <daniel@...ishbar.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Christian König <christian.koenig@....com>,
        Qiang Yu <yuq825@...il.com>,
        Steven Price <steven.price@....com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        Rob Herring <robh@...nel.org>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        kernel@...labora.com, virtualization@...ts.linux-foundation.org
Subject: [PATCH v11 08/10] drm/gem: Add drm_gem_pin_unlocked()

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.

Reviewed-by: Thomas Zimmermann <tzimmermann@...e.de>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@...labora.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 e5b2c077b314..3b16026e47f8 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 7bd8e2bbbb36..b0a03d2dac99 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,
 
 int drm_gem_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__ */
-- 
2.39.2