iommu: Add is_attach_deferred call-back to iommu-ops

This new call-back will be used to check if the domain attach need be
deferred for now. If yes, the domain attach/detach will return directly.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3f6ea16..86581b1 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1283,6 +1283,10 @@ static int __iommu_attach_device(struct iommu_domain *domain,
                                 struct device *dev)
 {
        int ret;
+       if ((domain->ops->is_attach_deferred != NULL) &&
+           domain->ops->is_attach_deferred(domain, dev))
+               return 0;
+
        if (unlikely(domain->ops->attach_dev == NULL))
                return -ENODEV;
 
@@ -1324,6 +1328,10 @@ EXPORT_SYMBOL_GPL(iommu_attach_device);
 static void __iommu_detach_device(struct iommu_domain *domain,
                                  struct device *dev)
 {
+       if ((domain->ops->is_attach_deferred != NULL) &&
+           domain->ops->is_attach_deferred(domain, dev))
+               return;
+
        if (unlikely(domain->ops->detach_dev == NULL))
                return;
 

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2cb54ad..63983c9 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -225,6 +225,7 @@ struct iommu_ops {
        u32 (*domain_get_windows)(struct iommu_domain *domain);
 
        int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
+       bool (*is_attach_deferred)(struct iommu_domain *domain, struct device *dev);
 
        unsigned long pgsize_bitmap;
 };