[AMD Official Use Only - AMD Internal Distribution Only] -----Original Message----- From: dri-devel <dri-devel-boun...@lists.freedesktop.org> On Behalf Of David Francis Sent: Friday, July 11, 2025 10:54 PM To: dri-devel@lists.freedesktop.org Cc: tvrtko.ursu...@igalia.com; Kuehling, Felix <felix.kuehl...@amd.com>; Yat Sin, David <david.yat...@amd.com>; Freehill, Chris <chris.freeh...@amd.com>; Koenig, Christian <christian.koe...@amd.com>; dcostant...@meta.com; sruff...@meta.com; sim...@ffwll.ch; mrip...@kernel.org; tzimmerm...@suse.de; Francis, David <david.fran...@amd.com> Subject: [PATCH 1/2] drm: Add DRM prime interface to reassign GEM handle
CRIU restore of drm buffer objects requires the ability to create or import a buffer object with a specific gem handle. Add new drm ioctl DRM_IOCTL_GEM_CHANGE_HANDLE, which takes the gem handle of an object and moves that object to a specified new gem handle. This ioctl needs to call drm_prime_remove_buf_handle, but that function acquires the prime lock, which the ioctl needs to hold for other purposes. Make drm_prime_remove_buf_handle not acquire the prime lock, and change its other caller to reflect this. The rest of the kernel patches required to enable CRIU can be found at https://lore.kernel.org/dri-devel/20250617194536.538681-1-david.fran...@amd.com/ Signed-off-by: David Francis <david.fran...@amd.com> --- drivers/gpu/drm/drm_gem.c | 54 ++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_internal.h | 4 +++ drivers/gpu/drm/drm_ioctl.c | 1 + drivers/gpu/drm/drm_prime.c | 6 +--- include/uapi/drm/drm.h | 23 +++++++++++++++ 5 files changed, 83 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index c6240bab3fa5..3166230d0119 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -282,7 +282,12 @@ drm_gem_object_release_handle(int id, void *ptr, void *data) if (obj->funcs->close) obj->funcs->close(obj, file_priv); + mutex_lock(&file_priv->prime.lock); + drm_prime_remove_buf_handle(&file_priv->prime, id); + + mutex_unlock(&file_priv->prime.lock); + drm_vma_node_revoke(&obj->vma_node, file_priv); drm_gem_object_handle_put_unlocked(obj); @@ -933,6 +938,55 @@ drm_gem_open_ioctl(struct drm_device *dev, void *data, return ret; } +int drm_gem_change_handle_ioctl(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + struct drm_gem_change_handle *args = data; + struct drm_gem_object *obj; + int ret; + + if (!drm_core_check_feature(dev, DRIVER_GEM)) + return -EOPNOTSUPP; + + obj = drm_gem_object_lookup(file_priv, args->handle); + if (!obj) + return -ENOENT; + + if (args->handle == args->new_handle) + return 0; + + mutex_lock(&file_priv->prime.lock); + + spin_lock(&file_priv->table_lock); + ret = idr_alloc(&file_priv->object_idr, obj, + args->new_handle, args->new_handle + 1, GFP_NOWAIT); + spin_unlock(&file_priv->table_lock); + + if (ret < 0) + goto out_unlock; + + if (obj->dma_buf) { + ret = drm_prime_add_buf_handle(&file_priv->prime, obj->dma_buf, args->new_handle); + if (ret < 0) { + spin_lock(&file_priv->table_lock); + idr_remove(&file_priv->object_idr, args->new_handle); + spin_unlock(&file_priv->table_lock); + goto out_unlock; + } + + drm_prime_remove_buf_handle(&file_priv->prime, args->handle); + } + Added ret = 0 before out_unlock to ensure proper return value ret = 0; Thanks Jesse + spin_lock(&file_priv->table_lock); + idr_remove(&file_priv->object_idr, args->handle); + spin_unlock(&file_priv->table_lock); + +out_unlock: + mutex_unlock(&file_priv->prime.lock); + + return ret; +} + /** * drm_gem_open - initializes GEM file-private structures at devnode open time * @dev: drm_device which is being opened by userspace diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index b2b6a8e49dda..e9d5cdf7e033 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -85,6 +85,8 @@ int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data, void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv); void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv); +int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, + struct dma_buf *dma_buf, uint32_t handle); void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, uint32_t handle); @@ -168,6 +170,8 @@ int drm_gem_close_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv); int drm_gem_flink_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv); +int drm_gem_change_handle_ioctl(struct drm_device *dev, void *data, + struct drm_file *file_priv); int drm_gem_open_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv); void drm_gem_open(struct drm_device *dev, struct drm_file *file_private); diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index f593dc569d31..d8a24875a7ba 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -653,6 +653,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, DRM_RENDER_ALLOW), DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH), DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH), + DRM_IOCTL_DEF(DRM_IOCTL_GEM_CHANGE_HANDLE, +drm_gem_change_handle_ioctl, DRM_RENDER_ALLOW), DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, 0), diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index bdb51c8f262e..1f2e858e5000 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -93,7 +93,7 @@ struct drm_prime_member { struct rb_node handle_rb; }; -static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, +int drm_prime_add_buf_handle(struct drm_prime_file_private +*prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) { struct drm_prime_member *member; @@ -190,8 +190,6 @@ void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, { struct rb_node *rb; - mutex_lock(&prime_fpriv->lock); - rb = prime_fpriv->handles.rb_node; while (rb) { struct drm_prime_member *member; @@ -210,8 +208,6 @@ void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, rb = rb->rb_left; } } - - mutex_unlock(&prime_fpriv->lock); } void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv) diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 7fba37b94401..e3940b657e16 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -625,6 +625,21 @@ struct drm_gem_open { __u64 size; }; +/** + * struct drm_gem_change_handle - Argument for &DRM_IOCTL_GEM_CHANGE_HANDLE ioctl. + * @handle: The handle of a gem object. + * @new_handle: An available gem handle. + * + * This ioctl changes the handle of a GEM object to the specified one. + * The new handle must be unused. On success the old handle is closed + * and all further IOCTL should refer to the new handle only. + * Calls to DRM_IOCTL_PRIME_FD_TO_HANDLE will return the new handle. + */ +struct drm_gem_change_handle { + __u32 handle; + __u32 new_handle; +}; + /** * DRM_CAP_DUMB_BUFFER * @@ -1305,6 +1320,14 @@ extern "C" { */ #define DRM_IOCTL_SET_CLIENT_NAME DRM_IOWR(0xD1, struct drm_set_client_name) +/** + * DRM_IOCTL_GEM_CHANGE_HANDLE - Move an object to a different handle + * + * Some applications (notably CRIU) need objects to have specific gem handles. + * This ioctl changes the object at one gem handle to use a new gem handle. + */ +#define DRM_IOCTL_GEM_CHANGE_HANDLE DRM_IOWR(0xD2, struct drm_gem_change_handle) + /* * Device specific ioctls should only be in their respective headers * The device specific ioctl range is from 0x40 to 0x9f. -- 2.34.1
