From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754008AbeDJN3Q (ORCPT ); Tue, 10 Apr 2018 09:29:16 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43486 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753104AbeDJN3P (ORCPT ); Tue, 10 Apr 2018 09:29:15 -0400 Date: Tue, 10 Apr 2018 16:29:13 +0300 From: "Michael S. Tsirkin" To: Stefan Hajnoczi Cc: virtualization@lists.linux-foundation.org, syzkaller-bugs@googlegroups.com, Linus Torvalds , kvm@vger.kernel.org, jasowang@redhat.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH v2 2/2] vhost: return bool from *_access_ok() functions Message-ID: <20180410162838-mutt-send-email-mst@kernel.org> References: <20180410052630.11270-1-stefanha@redhat.com> <20180410052630.11270-3-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180410052630.11270-3-stefanha@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 10, 2018 at 01:26:30PM +0800, Stefan Hajnoczi wrote: > Currently vhost *_access_ok() functions return int. This is error-prone > because there are two popular conventions: > > 1. 0 means failure, 1 means success > 2. -errno means failure, 0 means success > > Although vhost mostly uses #1, it does not do so consistently. > umem_access_ok() uses #2. > > This patch changes the return type from int to bool so that false means > failure and true means success. This eliminates a potential source of > errors. > > Suggested-by: Linus Torvalds > Signed-off-by: Stefan Hajnoczi Acked-by: Michael S. Tsirkin > --- > drivers/vhost/vhost.h | 4 ++-- > drivers/vhost/vhost.c | 66 +++++++++++++++++++++++++-------------------------- > 2 files changed, 35 insertions(+), 35 deletions(-) > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > index ac4b6056f19a..6e00fa57af09 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -178,8 +178,8 @@ void vhost_dev_cleanup(struct vhost_dev *); > void vhost_dev_stop(struct vhost_dev *); > long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp); > long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp); > -int vhost_vq_access_ok(struct vhost_virtqueue *vq); > -int vhost_log_access_ok(struct vhost_dev *); > +bool vhost_vq_access_ok(struct vhost_virtqueue *vq); > +bool vhost_log_access_ok(struct vhost_dev *); > > int vhost_get_vq_desc(struct vhost_virtqueue *, > struct iovec iov[], unsigned int iov_count, > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 93fd0c75b0d8..b6a082ef33dd 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -641,14 +641,14 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > } > EXPORT_SYMBOL_GPL(vhost_dev_cleanup); > > -static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz) > +static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz) > { > u64 a = addr / VHOST_PAGE_SIZE / 8; > > /* Make sure 64 bit math will not overflow. */ > if (a > ULONG_MAX - (unsigned long)log_base || > a + (unsigned long)log_base > ULONG_MAX) > - return 0; > + return false; > > return access_ok(VERIFY_WRITE, log_base + a, > (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); > @@ -661,30 +661,30 @@ static bool vhost_overflow(u64 uaddr, u64 size) > } > > /* Caller should have vq mutex and device mutex. */ > -static int vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem, > - int log_all) > +static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem, > + int log_all) > { > struct vhost_umem_node *node; > > if (!umem) > - return 0; > + return false; > > list_for_each_entry(node, &umem->umem_list, link) { > unsigned long a = node->userspace_addr; > > if (vhost_overflow(node->userspace_addr, node->size)) > - return 0; > + return false; > > > if (!access_ok(VERIFY_WRITE, (void __user *)a, > node->size)) > - return 0; > + return false; > else if (log_all && !log_access_ok(log_base, > node->start, > node->size)) > - return 0; > + return false; > } > - return 1; > + return true; > } > > static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, > @@ -701,13 +701,13 @@ static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, > > /* Can we switch to this memory table? */ > /* Caller should have device mutex but not vq mutex */ > -static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem, > - int log_all) > +static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem, > + int log_all) > { > int i; > > for (i = 0; i < d->nvqs; ++i) { > - int ok; > + bool ok; > bool log; > > mutex_lock(&d->vqs[i]->mutex); > @@ -717,12 +717,12 @@ static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem, > ok = vq_memory_access_ok(d->vqs[i]->log_base, > umem, log); > else > - ok = 1; > + ok = true; > mutex_unlock(&d->vqs[i]->mutex); > if (!ok) > - return 0; > + return false; > } > - return 1; > + return true; > } > > static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, > @@ -959,21 +959,21 @@ static void vhost_iotlb_notify_vq(struct vhost_dev *d, > spin_unlock(&d->iotlb_lock); > } > > -static int umem_access_ok(u64 uaddr, u64 size, int access) > +static bool umem_access_ok(u64 uaddr, u64 size, int access) > { > unsigned long a = uaddr; > > /* Make sure 64 bit math will not overflow. */ > if (vhost_overflow(uaddr, size)) > - return -EFAULT; > + return false; > > if ((access & VHOST_ACCESS_RO) && > !access_ok(VERIFY_READ, (void __user *)a, size)) > - return -EFAULT; > + return false; > if ((access & VHOST_ACCESS_WO) && > !access_ok(VERIFY_WRITE, (void __user *)a, size)) > - return -EFAULT; > - return 0; > + return false; > + return true; > } > > static int vhost_process_iotlb_msg(struct vhost_dev *dev, > @@ -988,7 +988,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev, > ret = -EFAULT; > break; > } > - if (umem_access_ok(msg->uaddr, msg->size, msg->perm)) { > + if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) { > ret = -EFAULT; > break; > } > @@ -1135,10 +1135,10 @@ static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) > return 0; > } > > -static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num, > - struct vring_desc __user *desc, > - struct vring_avail __user *avail, > - struct vring_used __user *used) > +static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num, > + struct vring_desc __user *desc, > + struct vring_avail __user *avail, > + struct vring_used __user *used) > > { > size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; > @@ -1161,8 +1161,8 @@ static void vhost_vq_meta_update(struct vhost_virtqueue *vq, > vq->meta_iotlb[type] = node; > } > > -static int iotlb_access_ok(struct vhost_virtqueue *vq, > - int access, u64 addr, u64 len, int type) > +static bool iotlb_access_ok(struct vhost_virtqueue *vq, > + int access, u64 addr, u64 len, int type) > { > const struct vhost_umem_node *node; > struct vhost_umem *umem = vq->iotlb; > @@ -1220,7 +1220,7 @@ EXPORT_SYMBOL_GPL(vq_iotlb_prefetch); > > /* Can we log writes? */ > /* Caller should have device mutex but not vq mutex */ > -int vhost_log_access_ok(struct vhost_dev *dev) > +bool vhost_log_access_ok(struct vhost_dev *dev) > { > return memory_access_ok(dev, dev->umem, 1); > } > @@ -1228,8 +1228,8 @@ EXPORT_SYMBOL_GPL(vhost_log_access_ok); > > /* Verify access for write logging. */ > /* Caller should have vq mutex and device mutex */ > -static int vq_log_access_ok(struct vhost_virtqueue *vq, > - void __user *log_base) > +static bool vq_log_access_ok(struct vhost_virtqueue *vq, > + void __user *log_base) > { > size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; > > @@ -1242,14 +1242,14 @@ static int vq_log_access_ok(struct vhost_virtqueue *vq, > > /* Can we start vq? */ > /* Caller should have vq mutex and device mutex */ > -int vhost_vq_access_ok(struct vhost_virtqueue *vq) > +bool vhost_vq_access_ok(struct vhost_virtqueue *vq) > { > if (!vq_log_access_ok(vq, vq->log_base)) > - return 0; > + return false; > > /* Access validation occurs at prefetch time with IOTLB */ > if (vq->iotlb) > - return 1; > + return true; > > return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); > } > -- > 2.14.3