drm: Return error codes from struct drm_driver.gem_create_object

GEM helper libraries use struct drm_driver.gem_create_object to let
drivers override GEM object allocation. On failure, the call returns
NULL.

Change the semantics to make the calls return a pointer-encoded error.
This aligns the callback with its callers. Fixes the ingenic driver,
which already returns an error pointer.

Also update the callers to handle the involved types more strictly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211130095255.26710-1-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 5f42e44b2ab356407365db02bef3bd1b3144c8e1..6f18f143dd3026fe10f62898b7f5a25e516d1879 100644 (file)
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -67,18 +67,21 @@ __drm_gem_cma_create(struct drm_device *drm, size_t size, bool private)
        struct drm_gem_object *gem_obj;
        int ret = 0;
 
-       if (drm->driver->gem_create_object)
+       if (drm->driver->gem_create_object) {
                gem_obj = drm->driver->gem_create_object(drm, size);
-       else
-               gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
-       if (!gem_obj)
-               return ERR_PTR(-ENOMEM);
+               if (IS_ERR(gem_obj))
+                       return ERR_CAST(gem_obj);
+               cma_obj = to_drm_gem_cma_obj(gem_obj);
+       } else {
+               cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
+               if (!cma_obj)
+                       return ERR_PTR(-ENOMEM);
+               gem_obj = &cma_obj->base;
+       }
 
        if (!gem_obj->funcs)
                gem_obj->funcs = &drm_gem_cma_default_funcs;
 
-       cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
-
        if (private) {
                drm_gem_private_object_init(drm, gem_obj, size);
 

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 0eeda1012364b33c89d0ac81ca82c51d0ee98fc2..7915047cb041ff043e192eaf69bb72e2ba943b36 100644 (file)
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -56,14 +56,17 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
 
        size = PAGE_ALIGN(size);
 
-       if (dev->driver->gem_create_object)
+       if (dev->driver->gem_create_object) {
                obj = dev->driver->gem_create_object(dev, size);
-       else
-               obj = kzalloc(sizeof(*shmem), GFP_KERNEL);
-       if (!obj)
-               return ERR_PTR(-ENOMEM);
-
-       shmem = to_drm_gem_shmem_obj(obj);
+               if (IS_ERR(obj))
+                       return ERR_CAST(obj);
+               shmem = to_drm_gem_shmem_obj(obj);
+       } else {
+               shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
+               if (!shmem)
+                       return ERR_PTR(-ENOMEM);
+               obj = &shmem->base;
+       }
 
        if (!obj->funcs)
                obj->funcs = &drm_gem_shmem_funcs;

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index bfa386b9813466fdfee8ab58283e316b26e896e7..3f00192215d11bb6a395a439151c8985517aacb7 100644 (file)
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -197,8 +197,8 @@ struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 
        if (dev->driver->gem_create_object) {
                gem = dev->driver->gem_create_object(dev, size);
-               if (!gem)
-                       return ERR_PTR(-ENOMEM);
+               if (IS_ERR(gem))
+                       return ERR_CAST(gem);
                gbo = drm_gem_vram_of_gem(gem);
        } else {
                gbo = kzalloc(sizeof(*gbo), GFP_KERNEL);

diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 2723d333c6083fd50ac86e16db5c8db51c8ba696..f9a9198ef19833861ed9bce00048026c603a47b2 100644 (file)
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -221,7 +221,7 @@ struct drm_gem_object *lima_gem_create_object(struct drm_device *dev, size_t siz
 
        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
        if (!bo)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        mutex_init(&bo->lock);
        INIT_LIST_HEAD(&bo->va);

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 6d9bdb9180cb7afe5aa596c38777d6e0dcd982fd..ead65f5fa2bcbae445fd01b10ba9a8e356f2ba78 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -223,7 +223,7 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t
 
        obj = kzalloc(sizeof(*obj), GFP_KERNEL);
        if (!obj)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        INIT_LIST_HEAD(&obj->mappings.list);
        mutex_init(&obj->mappings.lock);

diff --git a/drivers/gpu/drm/v3d/v3d_bo.c b/drivers/gpu/drm/v3d/v3d_bo.c
index 0d9af62f69ad16ee5914c4980bfb51b3da8c2933..6e3113f419f4ca641e8cd484018b0c4395c2f421 100644 (file)
--- a/drivers/gpu/drm/v3d/v3d_bo.c
+++ b/drivers/gpu/drm/v3d/v3d_bo.c
@@ -70,11 +70,11 @@ struct drm_gem_object *v3d_create_object(struct drm_device *dev, size_t size)
        struct drm_gem_object *obj;
 
        if (size == 0)
-               return NULL;
+               return ERR_PTR(-EINVAL);
 
        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
        if (!bo)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
        obj = &bo->base.base;
 
        obj->funcs = &v3d_gem_funcs;

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index a87eafa89e9f485983d4f1d3fc04885760084faf..c5e3e5457737754f0a09770e0e25a390e3d14e64 100644 (file)
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -97,7 +97,7 @@ static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, siz
 
        obj = kzalloc(sizeof(*obj), GFP_KERNEL);
        if (!obj)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        /*
         * vgem doesn't have any begin/end cpu access ioctls, therefore must use

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 187e10da2f1773a89c53ba06916b1c0281ed17d3..baef2c5f2aafc9eeee6497b7b29f625a79009a2c 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -139,7 +139,7 @@ struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
 
        shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
        if (!shmem)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        dshmem = &shmem->base.base;
        dshmem->base.funcs = &virtio_gpu_shmem_funcs;

diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index da0c836fe8e1afdd17eb860464ad99ec4cc3dd26..f6159acb885695d65ff84b4f7380d9c7feb301c9 100644 (file)
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -291,8 +291,9 @@ struct drm_driver {
        /**
         * @gem_create_object: constructor for gem objects
         *
-        * Hook for allocating the GEM object struct, for use by the CMA and
-        * SHMEM GEM helpers.
+        * Hook for allocating the GEM object struct, for use by the CMA
+        * and SHMEM GEM helpers. Returns a GEM object on success, or an
+        * ERR_PTR()-encoded error code otherwise.
         */
        struct drm_gem_object *(*gem_create_object)(struct drm_device *dev,
                                                    size_t size);