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x86_64-redhat-linux-gnu) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 12 Oct 2026 14:59:38 +0200 Ketil Johnsen wrote: > +int panthor_fw_protm_init(struct drm_file *file, > + struct drm_panthor_protm_init *args) > +{ > + struct panthor_file *pfile = file->driver_priv; > + struct panthor_device *ptdev = pfile->ptdev; > + struct panthor_fw_section *protm_section = ptdev->fw->protm_section; > + struct drm_gem_object *obj; > + u32 vm_map_flags; > + int cookie, ret = 0; > + > + if (!capable(CAP_SYS_MODULE)) > + return -EPERM; > + > + if (args->pad) > + return -EINVAL; > + > + if (!protm_section || !protm_section->size) > + return -EINVAL; > + > + guard(mutex)(&ptdev->fw->protm_init_lock); > + > + /* Thread safe access so other readers do not need protm_init_lock */ > + if (smp_load_acquire(&ptdev->protm.info.state) & > + DRM_PANTHOR_PROTM_INITIALIZED) > + return 0; Why not force the query to be done with the lock held instead? Querying the PROTM state is not a hot path, so the lockless approach feels overkill to me. If the problem is that the lock is not visible from ptdev, then I'd argue the ptdev->protm.info shouldn't be either, because it's not initialized at probe time. What we should have instead is a panthor_fw_query_protm_info() helper return/filling drm_panthor_protm_info. > + > + if (!drm_dev_enter(&ptdev->base, &cookie)) > + return -ENODEV; > + > + obj = drm_gem_object_lookup(file, > + args->fw_protected_sections_bo_handle); > + if (!obj) { > + ret = -ENOENT; > + goto out_dev_exit; > + } > + > + if (obj->size < ptdev->protm.info.fw_protected_sections_size) { > + ret = -EINVAL; > + goto out_gem_put; > + } > + > + vm_map_flags = section_vm_map_flags(protm_section); > + > + protm_section->mem = panthor_kernel_bo_create_from_gem( > + ptdev, panthor_fw_vm(ptdev), to_panthor_bo(obj), vm_map_flags, > + protm_section->va, protm_section->size); > + if (IS_ERR(protm_section->mem)) { > + ret = PTR_ERR(protm_section->mem); > + protm_section->mem = NULL; > + goto out_gem_put; > + } > + > + /* Make sure all above is completed before we update state */ > + smp_store_release(&ptdev->protm.info.state, > + DRM_PANTHOR_PROTM_INITIALIZED); > + > +out_gem_put: > + drm_gem_object_put(obj); > + > +out_dev_exit: > + drm_dev_exit(cookie); > + return ret; > +}