Re: [PATCH v5 07/10] KVM: arm/arm64: vgic-its: New helper functions to free the caches

Christoffer Dall
2017-10-25T10:31:28Z

On Mon, Oct 23, 2017 at 04:08:26PM +0200, Eric Auger wrote:
> From: wanghaibin <wanghaibin.wang@huawei.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@huawei.com>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>

> ---
>
> 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 | 51 ++++++++++++++++++++++----------------------
> 1 file changed, 26 insertions(+), 25 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 2f3c3a1..8098f91 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -910,6 +910,30 @@ static void vgic_its_free_device(struct kvm *kvm, struct its_device *device)
> kfree(device);
> }
>
> +static void vgic_its_free_device_list(struct kvm *kvm, struct vgic_its *its)
> +{
> + struct its_device *cur, *temp;
> +
> + mutex_lock(&its->its_lock);
> +
> + list_for_each_entry_safe(cur, temp, &its->device_list, dev_list)
> + vgic_its_free_device(kvm, cur);
> +
> + mutex_unlock(&its->its_lock);
> +}
> +
> +static void vgic_its_free_collection_list(struct kvm *kvm, struct vgic_its *its)
> +{
> + struct its_collection *cur, *temp;
> +
> + mutex_lock(&its->its_lock);
> +
> + list_for_each_entry_safe(cur, temp, &its->collection_list, coll_list)
> + vgic_its_free_collection(its, cur->collection_id);
> +
> + mutex_unlock(&its->its_lock);
> +}
> +
> /* 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 +1651,9 @@ 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;
> -
> - coll = list_entry(cur, struct its_collection, coll_list);
> - list_del(cur);
> - kfree(coll);
> - }
> - mutex_unlock(&its->its_lock);
>
> + vgic_its_free_device_list(kvm, its);
> + vgic_its_free_collection_list(kvm, its);
> kfree(its);
> }
>
> --
> 2.5.5
>