linux-kernel - [PATCH v2 2/3] drm: shmem: Add drm_gem_shmem_map

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Message-Id: <20190516141447.46839-3-steven.price@arm.com>
Date:   Thu, 16 May 2019 15:14:46 +0100
From:   Steven Price <steven.price@....com>
To:     Daniel Vetter <daniel@...ll.ch>, Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc:     Steven Price <steven.price@....com>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        David Airlie <airlied@...ux.ie>,
        Inki Dae <inki.dae@...sung.com>,
        Joonyoung Shim <jy0922.shim@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] drm: shmem: Add drm_gem_shmem_map_offset() wrapper

Provide a wrapper for drm_gem_map_offset() for clients of shmem. This
wrapper provides the correct semantics for the drm_gem_shmem_mmap()
callback.

Signed-off-by: Steven Price <steven.price@....com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 20 ++++++++++++++++++++
 include/drm/drm_gem_shmem_helper.h     |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 1ee208c2c85e..9dbebc4897d1 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -400,6 +400,26 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
 }
 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
 
+/**
+ * drm_gem_map_offset - return the fake mmap offset for a gem object
+ * @file: drm file-private structure containing the gem object
+ * @dev: corresponding drm_device
+ * @handle: gem object handle
+ * @offset: return location for the fake mmap offset
+ *
+ * This provides an offset suitable for user space to return to the
+ * drm_gem_shmem_mmap() callback via an mmap() call.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_map_offset(struct drm_file *file, struct drm_device *dev,
+			     u32 handle, u64 *offset)
+{
+	return drm_gem_map_offset(file, dev, handle, offset);
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_map_offset);
+
 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index 038b6d313447..4239ddaaaa4f 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -128,6 +128,8 @@ drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
 			      struct drm_mode_create_dumb *args);
 
+int drm_gem_shmem_map_offset(struct drm_file *file, struct drm_device *dev,
+			     u32 handle, u64 *offset);
 int drm_gem_shmem_mmap(struct file *filp, struct vm_area_struct *vma);
 
 extern const struct vm_operations_struct drm_gem_shmem_vm_ops;
-- 
2.20.1