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@ideasonboard.com Reviewed-by: Rob Clark robdclark@gmail.com --- 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>