Re: [PATCH] KVM: s390: Fix KVM_S390_GET_CMMA_BITS ioctl definition

From: Gleb Fotengauer-Malinovskiy
Date: Mon Jul 10 2017 - 17:23:40 EST


On Mon, Jul 10, 2017 at 08:43:12PM +0200, Christian Borntraeger wrote:
> On 07/10/2017 04:44 PM, Gleb Fotengauer-Malinovskiy wrote:
> > This ioctl actually writes to parameter too.
>
> Maybe rephrase that to:
> The kernel does not only read struct kvm_s390_cmma_log for KVM_S390_GET_CMMA_BITS,
> it also writes back a return value making this _IOWR instead of _IOW.

Ok, see v2.

> > Fixes: 4036e387 ("KVM: s390: ioctls to get and set guest storage attributes")
> > Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@xxxxxxxxxxxx>
> Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>
>
> Out of curiosity, how did you notice that?

I regenerated strace's ioctl lists. It was obvious from the diff that
*GET* and *SET* could not be both _IOC_WRITE.

--
glebfm