[Devel] [PATCH vz8 4/7] kvm: use _safe version of list iteration in mmu_shrink_scan()

[Konstantin Khorenko]

merged into previous patch:
[PATCH vz8 3/7] kvm: move VMs which we skip during shrink to vm_list tail

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 06/08/2021 08:58 PM, Valeriy Vdovin wrote:
> From: Konstantin Khorenko <khorenko at virtuozzo.com>
>
> As we skip some VMs during shrink and don't want to iterate them again
> and again on each shrink, we move those skipped VMs to the list's tail,
> thus we need to use _safe version of list iteration.
>
> Fixes: bb2d7ab43eba ("kvm: move VMs which we skip during shrink to vm_list
> tail")
> https://jira.sw.ru/browse/PSBM-95077
>
> Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
> (cherry-picked from bde385cf90bf89b255fe56f90605c07da5577a9e)
> https://jira.sw.ru/browse/PSBM-127849
> Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
> ---
>  arch/x86/kvm/mmu/mmu.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 74456f4a738a..9e58984fdfaf 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -6074,13 +6074,13 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
>  static unsigned long
>  mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
>  {
> -	struct kvm *kvm;
> +	struct kvm *kvm, *tmp;
>  	int nr_to_scan = sc->nr_to_scan;
>  	unsigned long freed = 0;
>
>  	mutex_lock(&kvm_lock);
>
> -	list_for_each_entry(kvm, &vm_list, vm_list) {
> +	list_for_each_entry_safe(kvm, tmp, &vm_list, vm_list) {
>  		int idx;
>  		LIST_HEAD(invalid_list);
>
>