Re: [PATCH 4/7] KVM: selftests: Add helpers to consolidate open coded list operations

[Peter Xu <peterx@redhat.com>]

On Fri, Mar 20, 2020 at 01:55:43PM -0700, Sean Christopherson wrote:
> Add helpers for the KVM sefltests' variant of a linked list to replace a
> variety of open coded adds, deletes and iterators.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  tools/testing/selftests/kvm/lib/kvm_util.c | 68 ++++++++++++----------
>  1 file changed, 37 insertions(+), 31 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 9a783c20dd26..d7b74f465570 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -19,6 +19,27 @@
>  #define KVM_UTIL_PGS_PER_HUGEPG 512
>  #define KVM_UTIL_MIN_PFN	2
>  
> +#define kvm_list_add(head, new)		\
> +do {					\
> +	if (head)			\
> +		head->prev = new;	\
> +	new->next = head;		\
> +	head = new;			\
> +} while (0)
> +
> +#define kvm_list_del(head, del)			\
> +do {						\
> +	if (del->next)				\
> +		del->next->prev = del->prev;	\
> +	if (del->prev)				\
> +		del->prev->next = del->next;	\
> +	else					\
> +		head = del->next;		\
> +} while (0)
> +
> +#define kvm_list_for_each(head, iter)		\
> +	for (iter = head; iter; iter = iter->next)
> +

I'm not sure whether we should start to use a common list, e.g.,
tools/include/linux/list.h, if we're going to rework them after all...
Even if this is preferred, maybe move to a header so kvm selftests can
use it in the future outside "vcpu" struct too and this file only?

Thanks,

-- 
Peter Xu