To avoid accidental removal of an active IOMMU driver module, take a reference to the driver module in 'iommu_probe_device()' immediately prior to invoking the '->add_device()' callback and hold it until the after the device has been removed by '->remove_device()'.
Suggested-by: Joerg Roedel <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- drivers/iommu/iommu.c | 19 +++++++++++++++++-- include/linux/iommu.h | 4 +++- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 7c92197d53f3..bc8edf90e729 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -22,6 +22,7 @@ #include <linux/bitops.h> #include <linux/property.h> #include <linux/fsl/mc.h> +#include <linux/module.h> #include <trace/events/iommu.h> static struct kset *iommu_group_kset; @@ -185,10 +186,21 @@ int iommu_probe_device(struct device *dev) if (!iommu_get_dev_param(dev)) return -ENOMEM; + if (!try_module_get(ops->owner)) { + ret = -EINVAL; + goto err_free_dev_param; + } + ret = ops->add_device(dev); if (ret) - iommu_free_dev_param(dev); + goto err_module_put; + + return 0; +err_module_put: + module_put(ops->owner); +err_free_dev_param: + iommu_free_dev_param(dev); return ret; } @@ -199,7 +211,10 @@ void iommu_release_device(struct device *dev) if (dev->iommu_group) ops->remove_device(dev); - iommu_free_dev_param(dev); + if (dev->iommu_param) { + module_put(ops->owner); + iommu_free_dev_param(dev); + } } static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus, diff --git a/include/linux/iommu.h b/include/linux/iommu.h index f2223cbb5fd5..e9f94d3f7a04 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -246,9 +246,10 @@ struct iommu_iotlb_gather { * @sva_get_pasid: Get PASID associated to a SVA handle * @page_response: handle page request response * @cache_invalidate: invalidate translation caches - * @pgsize_bitmap: bitmap of all possible supported page sizes * @sva_bind_gpasid: bind guest pasid and mm * @sva_unbind_gpasid: unbind guest pasid and mm + * @pgsize_bitmap: bitmap of all possible supported page sizes + * @owner: Driver module providing these ops */ struct iommu_ops { bool (*capable)(enum iommu_cap); @@ -318,6 +319,7 @@ struct iommu_ops { int (*sva_unbind_gpasid)(struct device *dev, int pasid); unsigned long pgsize_bitmap; + struct module *owner; }; /** -- 2.24.1.735.g03f4e72817-goog _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
