Re: [PATCH v5 9/9] KVM: s390: Return failure in case of failure in kvm_s390_set_cmma_bits()

[Christian Borntraeger]

Am 22.06.26 um 18:07 schrieb Claudio Imbrenda:
> If the allocation of the bits array failed, kvm_s390_set_cmma_bits()
> would return 0 instead of an error code.
>
> Rework the function to use the __free() macros and thus simplify the
> code flow; when the above mentioned allocation fails, simply return
> -ENOMEM.
>
> Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> ---
>   arch/s390/kvm/kvm-s390.c | 18 +++++++-----------
>   1 file changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index cdd8b41d24ed..27d6004132d2 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2282,8 +2282,8 @@ static int kvm_s390_get_cmma_bits(struct kvm *kvm,
>   static int kvm_s390_set_cmma_bits(struct kvm *kvm,
>   				  const struct kvm_s390_cmma_log *args)
>   {
> -	struct kvm_s390_mmu_cache *mc;
> -	u8 *bits = NULL;
> +	struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) = NULL;
> +	u8 *bits __free(kvfree) = NULL;

why kvfree and not vfree?

>   	int r = 0;
>   
>   	if (!kvm->arch.use_cmma)
> @@ -2303,18 +2303,16 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm,
>   		return -ENOMEM;
>   	bits = vmalloc(array_size(sizeof(*bits), args->count));
>   	if (!bits)
> -		goto out;
> +		return -ENOMEM;
>   
>   	r = copy_from_user(bits, (void __user *)args->values, args->count);
> -	if (r) {
> -		r = -EFAULT;
> -		goto out;
> -	}
> +	if (r)
> +		return -EFAULT;
>   
>   	do {
>   		r = kvm_s390_mmu_cache_topup(mc);
>   		if (r)
> -			break;
> +			return r;
>   		scoped_guard(read_lock, &kvm->mmu_lock) {
>   			r = dat_set_cmma_bits(mc, kvm->arch.gmap->asce, args->start_gfn,
>   					      args->count, args->mask, bits);
> @@ -2322,9 +2320,7 @@ static int kvm_s390_set_cmma_bits(struct kvm *kvm,
>   	} while (r == -ENOMEM);
>   
>   	set_bit(GMAP_FLAG_USES_CMM, &kvm->arch.gmap->flags);
> -out:
> -	kvm_s390_free_mmu_cache(mc);
> -	vfree(bits);
> +
>   	return r;
>   }
>