[PATCH 3/7] vfio: iommu_type1: Make an explicit "promote" semantic

[Keqian Zhu]

When we want to promote pinned_page_scope of vfio_iommu, we
should call the "update" function to visit all vfio_group,
but when we want to downgrade it, we can set the flag directly.

Giving above, we can give an explicit "promote" semantic to
that function. BTW, if vfio_iommu has been promoted, then it
can return early.

Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index c52bcefba96b..bd9a94590ebc 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -148,7 +148,7 @@ static int put_pfn(unsigned long pfn, int prot);
 static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
                                               struct iommu_group *iommu_group);
 
-static void update_pinned_page_dirty_scope(struct vfio_iommu *iommu);
+static void promote_pinned_page_dirty_scope(struct vfio_iommu *iommu);
 /*
  * This code handles mapping and unmapping of user data buffers
  * into DMA'ble space using the IOMMU
@@ -719,7 +719,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
        group = vfio_iommu_find_iommu_group(iommu, iommu_group);
        if (!group->pinned_page_dirty_scope) {
                group->pinned_page_dirty_scope = true;
-               update_pinned_page_dirty_scope(iommu);
+               promote_pinned_page_dirty_scope(iommu);
        }
 
        goto pin_done;
@@ -1633,27 +1633,26 @@ static struct vfio_group 
*vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
        return group;
 }
 
-static void update_pinned_page_dirty_scope(struct vfio_iommu *iommu)
+static void promote_pinned_page_dirty_scope(struct vfio_iommu *iommu)
 {
        struct vfio_domain *domain;
        struct vfio_group *group;
 
+       if (iommu->pinned_page_dirty_scope)
+               return;
+
        list_for_each_entry(domain, &iommu->domain_list, next) {
                list_for_each_entry(group, &domain->group_list, next) {
-                       if (!group->pinned_page_dirty_scope) {
-                               iommu->pinned_page_dirty_scope = false;
+                       if (!group->pinned_page_dirty_scope)
                                return;
-                       }
                }
        }
 
        if (iommu->external_domain) {
                domain = iommu->external_domain;
                list_for_each_entry(group, &domain->group_list, next) {
-                       if (!group->pinned_page_dirty_scope) {
-                               iommu->pinned_page_dirty_scope = false;
+                       if (!group->pinned_page_dirty_scope)
                                return;
-                       }
                }
        }
 
@@ -2348,7 +2347,7 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_domain *domain;
        struct vfio_group *group;
-       bool update_dirty_scope = false;
+       bool promote_dirty_scope = false;
        LIST_HEAD(iova_copy);
 
        mutex_lock(&iommu->lock);
@@ -2356,7 +2355,7 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
        if (iommu->external_domain) {
                group = find_iommu_group(iommu->external_domain, iommu_group);
                if (group) {
-                       update_dirty_scope = !group->pinned_page_dirty_scope;
+                       promote_dirty_scope = !group->pinned_page_dirty_scope;
                        list_del(&group->next);
                        kfree(group);
 
@@ -2386,7 +2385,7 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
                        continue;
 
                vfio_iommu_detach_group(domain, group);
-               update_dirty_scope = !group->pinned_page_dirty_scope;
+               promote_dirty_scope = !group->pinned_page_dirty_scope;
                list_del(&group->next);
                kfree(group);
                /*
@@ -2422,8 +2421,8 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
         * Removal of a group without dirty tracking may allow the iommu scope
         * to be promoted.
         */
-       if (update_dirty_scope)
-               update_pinned_page_dirty_scope(iommu);
+       if (promote_dirty_scope)
+               promote_pinned_page_dirty_scope(iommu);
        mutex_unlock(&iommu->lock);
 }
 
-- 
2.23.0