iommu: Export bus_iommu_probe() and make is safe for re-probing

Add a check to the bus_iommu_probe() call-path to make sure it ignores
devices which have already been successfully probed. Then export the
bus_iommu_probe() function so it can be used by IOMMU drivers.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-14-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 834a45d..397fd4f 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1610,11 +1610,19 @@ static int probe_iommu_group(struct device *dev, void *data)
 {
        const struct iommu_ops *ops = dev->bus->iommu_ops;
        struct list_head *group_list = data;
+       struct iommu_group *group;
        int ret;
 
        if (!dev_iommu_get(dev))
                return -ENOMEM;
 
+       /* Device is probed already if in a group */
+       group = iommu_group_get(dev);
+       if (group) {
+               iommu_group_put(group);
+               return 0;
+       }
+
        if (!try_module_get(ops->owner)) {
                ret = -EINVAL;
                goto err_free_dev_iommu;
@@ -1783,7 +1791,7 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group)
                                          iommu_do_create_direct_mappings);
 }
 
-static int bus_iommu_probe(struct bus_type *bus)
+int bus_iommu_probe(struct bus_type *bus)
 {
        const struct iommu_ops *ops = bus->iommu_ops;
        int ret;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 30170d1..fea1622 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -445,6 +445,7 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
 #define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER      6 /* Post Driver unbind */
 
 extern int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops);
+extern int bus_iommu_probe(struct bus_type *bus);
 extern bool iommu_present(struct bus_type *bus);
 extern bool iommu_capable(struct bus_type *bus, enum iommu_cap cap);
 extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);