From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753557Ab0CQIPJ (ORCPT ); Wed, 17 Mar 2010 04:15:09 -0400 Received: from serv2.oss.ntt.co.jp ([222.151.198.100]:35309 "EHLO serv2.oss.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752025Ab0CQIPF (ORCPT ); Wed, 17 Mar 2010 04:15:05 -0400 Message-ID: <4BA09023.4000706@oss.ntt.co.jp> Date: Wed, 17 Mar 2010 17:17:39 +0900 From: Takuya Yoshikawa User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Xiao Guangrong CC: Avi Kivity , KVM list , LKML Subject: Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log() References: <4BA0897F.3050906@cn.fujitsu.com> In-Reply-To: <4BA0897F.3050906@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Xiao Guangrong wrote: > Using bitmap_empty() to see whether memslot->dirty_bitmap is empty > > Changlog: > cleanup x86 specific kvm_vm_ioctl_get_dirty_log() and fix a local > parameter's type address Takuya Yoshikawa's suggestion Oh, for such a tiny comment. > > Signed-off-by: Xiao Guangrong > --- > arch/x86/kvm/x86.c | 17 ++++------------- > virt/kvm/kvm_main.c | 7 ++----- > 2 files changed, 6 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index bcf52d1..e6cbbd4 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c What I said was just you may be able to use bitmap_empty() instead of > - for (i = 0; !is_dirty && i < n/sizeof(long); i++) > - is_dirty = memslot->dirty_bitmap[i]; for x86's code too, if your patch for kvm_get_dirty_log() was correct. > @@ -2644,22 +2644,17 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm, > int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, > struct kvm_dirty_log *log) > { > - int r, n, i; > + int r, n, is_dirty = 0; > struct kvm_memory_slot *memslot; > - unsigned long is_dirty = 0; > unsigned long *dirty_bitmap = NULL; > > mutex_lock(&kvm->slots_lock); > > - r = -EINVAL; > - if (log->slot >= KVM_MEMORY_SLOTS) > + r = kvm_get_dirty_log(kvm, log, &is_dirty); > + if (r) > goto out; > > memslot = &kvm->memslots->memslots[log->slot]; > - r = -ENOENT; > - if (!memslot->dirty_bitmap) > - goto out; > - > n = ALIGN(memslot->npages, BITS_PER_LONG) / 8; > > r = -ENOMEM; > @@ -2668,9 +2663,6 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, > goto out; > memset(dirty_bitmap, 0, n); > > - for (i = 0; !is_dirty && i < n/sizeof(long); i++) > - is_dirty = memslot->dirty_bitmap[i]; > - > /* If nothing is dirty, don't bother messing with page tables. */ > if (is_dirty) { > struct kvm_memslots *slots, *old_slots; > @@ -2694,8 +2686,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, > } > > r = 0; > - if (copy_to_user(log->dirty_bitmap, dirty_bitmap, n)) > - r = -EFAULT; > + > out_free: > vfree(dirty_bitmap); > out: > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index bcd08b8..b08a7de 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -767,9 +767,7 @@ int kvm_get_dirty_log(struct kvm *kvm, > struct kvm_dirty_log *log, int *is_dirty) > { > struct kvm_memory_slot *memslot; > - int r, i; > - int n; > - unsigned long any = 0; > + int r, n, any = 0; > > r = -EINVAL; > if (log->slot >= KVM_MEMORY_SLOTS) > @@ -782,8 +780,7 @@ int kvm_get_dirty_log(struct kvm *kvm, > > n = ALIGN(memslot->npages, BITS_PER_LONG) / 8; > > - for (i = 0; !any && i < n/sizeof(long); ++i) > - any = memslot->dirty_bitmap[i]; > + any = !bitmap_empty(memslot->dirty_bitmap, memslot->npages); > > r = -EFAULT; > if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))