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vhost: switch to __get/__put_user exclusively 

Most places in vhost can use __get/__put_user rather than
get/put_user since addresses are pre-validated.
This should be good for performance, but this also
will help make code sparse-clean: get/put_user macros
don't play well with __virtioXX bitwise tags.
Switch to get/put_user to __ variants everywhere in vhost.
There's one exception - for consistency switch that
as well, and add an explicit access_ok check.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hifive-unleashed-5.1
Michael S. Tsirkin 2014-12-01 17:39:39 +02:00
parent bf99573496
commit 64f7f0510c
1 changed files with 10 additions and 3 deletions
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13
drivers/vhost/vhost.c
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@ -1038,6 +1038,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
int vhost_init_used(struct vhost_virtqueue *vq)
{
u16 last_used_idx;
int r;
if (!vq->private_data)
return 0;
@ -1046,7 +1047,13 @@ int vhost_init_used(struct vhost_virtqueue *vq)
if (r)
return r;
vq->signalled_used_valid = false;
return get_user(vq->last_used_idx, &vq->used->idx);
if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx))
return -EFAULT;
r = __get_user(last_used_idx, &vq->used->idx);
if (r)
return r;
vq->last_used_idx = last_used_idx;
return 0;
}
EXPORT_SYMBOL_GPL(vhost_init_used);
@ -1404,7 +1411,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
/* Make sure buffer is written before we update index. */
smp_wmb();
if (put_user(vq->last_used_idx, &vq->used->idx)) {
if (__put_user(vq->last_used_idx, &vq->used->idx)) {
vq_err(vq, "Failed to increment used idx");
return -EFAULT;
}
@ -1449,7 +1456,7 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
if (unlikely(!v))
return true;
if (get_user(event, vhost_used_event(vq))) {
if (__get_user(event, vhost_used_event(vq))) {
vq_err(vq, "Failed to get used event idx");
return true;
}