The drm_gem_mmap() function first finds the GEM object to be mapped
based on the fake mmap offset and then maps the object. Split the object
mapping code into a standalone drm_gem_mmap_obj() function that can be
used to implement dma-buf mmap() operations.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_gem.c | 83 +++++++++++++++++++++++++++++------------------
include/drm/drmP.h | 2 ++
2 files changed, 54 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index cf919e3..4321713 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -644,6 +644,55 @@ void drm_gem_vm_close(struct vm_area_struct *vma)
}
EXPORT_SYMBOL(drm_gem_vm_close);
+/**
+ * drm_gem_mmap_obj - memory map a GEM object
+ * @obj: the GEM object to map
+ * @obj_size: the object size to be mapped, in bytes
+ * @vma: VMA for the area to be mapped
+ *
+ * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
+ * provided by the driver. Depending on their requirements, drivers can either
+ * provide a fault handler in their gem_vm_ops (in which case any accesses to
+ * the object will be trapped, to perform migration, GTT binding, surface
+ * register allocation, or performance monitoring), or mmap the buffer memory
+ * synchronously after calling drm_gem_mmap_obj.
+ *
+ * This function is mainly intended to implement the DMABUF mmap operation, when
+ * the GEM object is not looked up based on its fake offset. To implement the
+ * DRM mmap operation, drivers should use the drm_gem_mmap() function.
+ *
+ * Return 0 or success or -EINVAL if the object size is smaller than the VMA
+ * size, or if no gem_vm_ops are provided.
+ */
+int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
+ struct vm_area_struct *vma)
+{
+ struct drm_device *dev = obj->dev;
+
+ /* Check for valid size. */
+ if (obj_size < vma->vm_end - vma->vm_start)
+ return -EINVAL;
+
+ if (!dev->driver->gem_vm_ops)
+ return -EINVAL;
+
+ vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_ops = dev->driver->gem_vm_ops;
+ vma->vm_private_data = obj;
+ vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+
+ /* Take a ref for this mapping of the object, so that the fault
+ * handler can dereference the mmap offset's pointer to the object.
+ * This reference is cleaned up by the corresponding vm_close
+ * (which should happen whether the vma was created by this call, or
+ * by a vm_open due to mremap or partial unmap or whatever).
+ */
+ drm_gem_object_reference(obj);
+
+ drm_vm_open_locked(dev, vma);
+ return 0;
+}
+EXPORT_SYMBOL(drm_gem_mmap_obj);
/**
* drm_gem_mmap - memory map routine for GEM objects
@@ -653,11 +702,9 @@ EXPORT_SYMBOL(drm_gem_vm_close);
* If a driver supports GEM object mapping, mmap calls on the DRM file
* descriptor will end up here.
*
- * If we find the object based on the offset passed in (vma->vm_pgoff will
+ * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
* contain the fake offset we created when the GTT map ioctl was called on
- * the object), we set up the driver fault handler so that any accesses
- * to the object can be trapped, to perform migration, GTT binding, surface
- * register allocation, or performance monitoring.
+ * the object) and map it with a call to drm_gem_mmap_obj().
*/
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
@@ -665,7 +712,6 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
struct drm_device *dev = priv->minor->dev;
struct drm_gem_mm *mm = dev->mm_private;
struct drm_local_map *map = NULL;
- struct drm_gem_object *obj;
struct drm_hash_item *hash;
int ret = 0;
@@ -686,32 +732,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
goto out_unlock;
}
- /* Check for valid size. */
- if (map->size < vma->vm_end - vma->vm_start) {
- ret = -EINVAL;
- goto out_unlock;
- }
-
- obj = map->handle;
- if (!obj->dev->driver->gem_vm_ops) {
- ret = -EINVAL;
- goto out_unlock;
- }
-
- vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
- vma->vm_ops = obj->dev->driver->gem_vm_ops;
- vma->vm_private_data = map->handle;
- vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
- /* Take a ref for this mapping of the object, so that the fault
- * handler can dereference the mmap offset's pointer to the object.
- * This reference is cleaned up by the corresponding vm_close
- * (which should happen whether the vma was created by this call, or
- * by a vm_open due to mremap or partial unmap or whatever).
- */
- drm_gem_object_reference(obj);
-
- drm_vm_open_locked(dev, vma);
+ ret = drm_gem_mmap_obj(map->handle, map->size, vma);
out_unlock:
mutex_unlock(&dev->struct_mutex);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index b06f5af..79fb4c7 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1616,6 +1616,8 @@ int drm_gem_private_object_init(struct drm_device *dev,
void drm_gem_object_handle_free(struct drm_gem_object *obj);
void drm_gem_vm_open(struct vm_area_struct *vma);
void drm_gem_vm_close(struct vm_area_struct *vma);
+int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
+ struct vm_area_struct *vma);
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
#include <drm/drm_global.h>
--
1.8.1.5
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