KVM: arm/arm64: vgic-its: New helper functions to free the caches

We create two new functions that free the device and
collection lists. They are currently called by vgic_its_destroy()
and other callers will be added in subsequent patches.

We also remove the check on its->device_list.next.
Lists are initialized in vgic_create_its() and the device
is added to the device list only if this latter succeeds.

vgic_its_destroy is the device destroy ops. This latter is called
by kvm_destroy_devices() which loops on all created devices. So
at this point the list is initialized.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: wanghaibin <wanghaibin.wang@huawei.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 20 insertions, 21 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 75c18183eee3..d46256c07ba5 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -913,6 +913,24 @@ static void vgic_its_free_device(struct kvm *kvm, struct its_device *device)
         kfree(device);
 }
 
+/* its lock must be held */
+static void vgic_its_free_device_list(struct kvm *kvm, struct vgic_its *its)
+{
+        struct its_device *cur, *temp;
+
+        list_for_each_entry_safe(cur, temp, &its->device_list, dev_list)
+                vgic_its_free_device(kvm, cur);
+}
+
+/* its lock must be held */
+static void vgic_its_free_collection_list(struct kvm *kvm, struct vgic_its *its)
+{
+        struct its_collection *cur, *temp;
+
+        list_for_each_entry_safe(cur, temp, &its->collection_list, coll_list)
+                vgic_its_free_collection(its, cur->collection_id);
+}
+
 /* Must be called with its_lock mutex held */
 static struct its_device *vgic_its_alloc_device(struct vgic_its *its,
                                                 u32 device_id, gpa_t itt_addr,
@@ -1619,32 +1637,13 @@ static void vgic_its_destroy(struct kvm_device *kvm_dev)
 {
         struct kvm *kvm = kvm_dev->kvm;
         struct vgic_its *its = kvm_dev->private;
-        struct list_head *cur, *temp;
-
-        /*
-         * We may end up here without the lists ever having been initialized.
-         * Check this and bail out early to avoid dereferencing a NULL pointer.
-         */
-        if (!its->device_list.next)
-                return;
 
         mutex_lock(&its->its_lock);
-        list_for_each_safe(cur, temp, &its->device_list) {
-                struct its_device *dev;
 
-                dev = list_entry(cur, struct its_device, dev_list);
-                vgic_its_free_device(kvm, dev);
-        }
-
-        list_for_each_safe(cur, temp, &its->collection_list) {
-                struct its_collection *coll;
+        vgic_its_free_device_list(kvm, its);
+        vgic_its_free_collection_list(kvm, its);
 
-                coll = list_entry(cur, struct its_collection, coll_list);
-                list_del(cur);
-                kfree(coll);
-        }
         mutex_unlock(&its->its_lock);
-
         kfree(its);
 }