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Fri, 11 Sep 2020 10:23:42 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id v6sm5589531wrt.90.2020.09.11.10.23.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Sep 2020 10:23:42 -0700 (PDT) Subject: Re: [PATCH] kvm/eventfd:do wildcard calculation before list_for_each_entry_safe To: Yi Li Cc: yilikernel@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <20200911055652.3041762-1-yili@winhong.com> From: Paolo Bonzini Message-ID: <20efe3ed-8efa-ed50-bd01-329db676ee86@redhat.com> Date: Fri, 11 Sep 2020 19:23:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200911055652.3041762-1-yili@winhong.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/09/20 07:56, Yi Li wrote: > There is no need to calculate wildcard in each loop > since wildcard is not changed. > > Signed-off-by: Yi Li > --- > virt/kvm/eventfd.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > index d6408bb497dc..c2323c27a28b 100644 > --- a/virt/kvm/eventfd.c > +++ b/virt/kvm/eventfd.c > @@ -853,15 +853,17 @@ kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx, > struct eventfd_ctx *eventfd; > struct kvm_io_bus *bus; > int ret = -ENOENT; > + bool wildcard; > > eventfd = eventfd_ctx_fdget(args->fd); > if (IS_ERR(eventfd)) > return PTR_ERR(eventfd); > > + wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); > + > mutex_lock(&kvm->slots_lock); > > list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) { > - bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); > > if (p->bus_idx != bus_idx || > p->eventfd != eventfd || > Queued, thanks. Paolo