linux-kernel - [PATCH v6 6/9] KVM: arm/arm64: vgic-its: New helper functions to free the caches

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1509031391-4407-7-git-send-email-eric.auger@redhat.com>
Date:   Thu, 26 Oct 2017 17:23:08 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu, marc.zyngier@....com,
        cdall@...aro.org, peter.maydell@...aro.org, andre.przywara@....com,
        wanghaibin.wang@...wei.com
Cc:     wu.wubin@...wei.com, drjones@...hat.com, wei@...hat.com
Subject: [PATCH v6 6/9] KVM: arm/arm64: vgic-its: New helper functions to free the caches

From: wanghaibin <wanghaibin.wang@...wei.com>

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.

Signed-off-by: wanghaibin <wanghaibin.wang@...wei.com>
Signed-off-by: Eric Auger <eric.auger@...hat.com>

---
v5 -> v6:
- take the its lock in vgic_its_destroy() instead of in
  vgic_its_free_device_list and vgic_its_free_collection_list

v4 -> v5:
- add mutex_lock in vgic_its_free_collection_list
- use list_for_each_entry_safe
- reword commit message
---
 virt/kvm/arm/vgic/vgic-its.c | 41 ++++++++++++++++++++---------------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index d21c960..5b7be85 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -910,6 +910,24 @@ 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,
@@ -1627,32 +1645,13 @@ 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);
 }
 
-- 
2.5.5