From: Jason Gunthorpe Date: Tue, 16 Aug 2022 19:13:04 +0000 (-0300) Subject: vfio: Remove vfio_group dev_counter X-Git-Tag: v6.1-rc1~42^2~61 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=21c13829bc3b786bc5336470df023ae54e41d230;p=thirdparty%2Flinux.git vfio: Remove vfio_group dev_counter This counts the number of devices attached to a vfio_group, ie the number of items in the group->device_list. It is only read in vfio_pin_pages(), as some kind of protection against limitations in type1. However, with all the code cleanups in this area, now that vfio_pin_pages() accepts a vfio_device directly it is redundant. All drivers are already calling vfio_register_emulated_iommu_dev() which directly creates a group specifically for the device and thus it is guaranteed that there is a singleton group. Leave a note in the comment about this requirement and remove the logic. Reviewed-by: Yi Liu Signed-off-by: Jason Gunthorpe Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/0-v2-d4374a7bf0c9+c4-vfio_dev_counter_jgg@nvidia.com Signed-off-by: Alex Williamson --- diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 5edc49748013d..77264d836d520 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -75,7 +75,6 @@ struct vfio_group { struct list_head vfio_next; struct list_head container_next; enum vfio_group_type type; - unsigned int dev_counter; struct rw_semaphore group_rwsem; struct kvm *kvm; struct file *opened_file; @@ -609,7 +608,6 @@ static int __vfio_register_dev(struct vfio_device *device, mutex_lock(&group->device_lock); list_add(&device->group_next, &group->device_list); - group->dev_counter++; mutex_unlock(&group->device_lock); return 0; @@ -697,7 +695,6 @@ void vfio_unregister_group_dev(struct vfio_device *device) mutex_lock(&group->device_lock); list_del(&device->group_next); - group->dev_counter--; mutex_unlock(&group->device_lock); if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU) @@ -1991,6 +1988,9 @@ EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare); * @prot [in] : protection flags * @pages[out] : array of host pages * Return error or number of pages pinned. + * + * A driver may only call this function if the vfio_device was created + * by vfio_register_emulated_iommu_dev(). */ int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova, int npage, int prot, struct page **pages) @@ -2006,9 +2006,6 @@ int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova, if (npage > VFIO_PIN_PAGES_MAX_ENTRIES) return -E2BIG; - if (group->dev_counter > 1) - return -EINVAL; - /* group->container cannot change while a vfio device is open */ container = group->container; driver = container->iommu_driver;