vhost: return bool from *_access_ok() functions

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 <torvalds@linux-foundation.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 33 insertions, 33 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 9a18535fafba..f3bd8e941224 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);
 }