drm: add mmap() to drm_gem_object_funcs

drm_gem_object_funcs->vm_ops alone can't handle everything which needs
to be done for mmap(), tweaking vm_flags for example.  So add a new
mmap() callback to drm_gem_object_funcs where this code can go to.

Note that the vm_ops field is not used in case the mmap callback is
present, it is expected that the callback sets vma->vm_ops instead.

Also setting vm_flags and vm_page_prot is the job of the new callback.
so drivers have more control over these flags.

drm_gem_mmap_obj() will use the new callback for object specific mmap
setup.  With this in place the need for driver-speific fops->mmap
callbacks goes away, drm_gem_mmap can be hooked instead.

drm_gem_prime_mmap() will use the new callback too to just mmap gem
objects directly instead of jumping though loops to make
drm_gem_object_lookup() and fops->mmap work.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20191016115203.20095-2-kraxel@redhat.com

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 6854f5867d51bccea46465d92dfd7b32849ca851..56f42e0f25847e9ef5bdf3b539af24e69ab61630 100644 (file)
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1099,22 +1099,31 @@ 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;
+       int ret;
 
        /* Check for valid size. */
        if (obj_size < vma->vm_end - vma->vm_start)
                return -EINVAL;
 
-       if (obj->funcs && obj->funcs->vm_ops)
-               vma->vm_ops = obj->funcs->vm_ops;
-       else if (dev->driver->gem_vm_ops)
-               vma->vm_ops = dev->driver->gem_vm_ops;
-       else
-               return -EINVAL;
+       if (obj->funcs && obj->funcs->mmap) {
+               ret = obj->funcs->mmap(obj, vma);
+               if (ret)
+                       return ret;
+               WARN_ON(!(vma->vm_flags & VM_DONTEXPAND));
+       } else {
+               if (obj->funcs && obj->funcs->vm_ops)
+                       vma->vm_ops = obj->funcs->vm_ops;
+               else if (dev->driver->gem_vm_ops)
+                       vma->vm_ops = dev->driver->gem_vm_ops;
+               else
+                       return -EINVAL;
+
+               vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+               vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+               vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+       }
 
-       vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
        vma->vm_private_data = obj;
-       vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-       vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
 
        /* Take a ref for this mapping of the object, so that the fault
         * handler can dereference the mmap offset's pointer to the object.

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 0a2316e0e812196d318699596f73d079edb2fb66..0814211b0f3f309f1a266b01b1031203e27c88ac 100644 (file)
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -713,6 +713,15 @@ int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
        struct file *fil;
        int ret;
 
+       if (obj->funcs && obj->funcs->mmap) {
+               ret = obj->funcs->mmap(obj, vma);
+               if (ret)
+                       return ret;
+               vma->vm_private_data = obj;
+               drm_gem_object_get(obj);
+               return 0;
+       }
+
        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        fil = kzalloc(sizeof(*fil), GFP_KERNEL);
        if (!priv || !fil) {

diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 6aaba14f5972d2dd5c7a61fd91377de9d482f2fb..e71f75a2ab57feb6dd382ad0792a2bd8200cdb38 100644 (file)
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -150,6 +150,20 @@ struct drm_gem_object_funcs {
         */
        void (*vunmap)(struct drm_gem_object *obj, void *vaddr);
 
+       /**
+        * @mmap:
+        *
+        * Handle mmap() of the gem object, setup vma accordingly.
+        *
+        * This callback is optional.
+        *
+        * The callback is used by by both drm_gem_mmap_obj() and
+        * drm_gem_prime_mmap().  When @mmap is present @vm_ops is not
+        * used, the @mmap callback must set vma->vm_ops instead.
+        *
+        */
+       int (*mmap)(struct drm_gem_object *obj, struct vm_area_struct *vma);
+
        /**
         * @vm_ops:
         *