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Revert "net: vhost: lock the vqs one by one"

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This reverts commit 78139c94dc. We don't
protect device IOTLB with vq mutex, which will lead e.g use after free
for device IOTLB entries. And since we've switched to use
mutex_trylock() in previous patch, it's safe to revert it without
having deadlock.

Fixes: commit 78139c94dc ("net: vhost: lock the vqs one by one")
Cc: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2018-12-13 10:53:39 +08:00 committed by David S. Miller
parent 476e8ba712
commit 86a07da343
1 changed files with 17 additions and 4 deletions
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21
drivers/vhost/vhost.c
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@ -295,11 +295,8 @@ static void vhost_vq_meta_reset(struct vhost_dev *d)
{
int i;
for (i = 0; i < d->nvqs; ++i) {
mutex_lock(&d->vqs[i]->mutex);
for (i = 0; i < d->nvqs; ++i)
__vhost_vq_meta_reset(d->vqs[i]);
mutex_unlock(&d->vqs[i]->mutex);
}
}
static void vhost_vq_reset(struct vhost_dev *dev,
@ -895,6 +892,20 @@ static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
#define vhost_get_used(vq, x, ptr) \
vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
static void vhost_dev_lock_vqs(struct vhost_dev *d)
{
int i = 0;
for (i = 0; i < d->nvqs; ++i)
mutex_lock_nested(&d->vqs[i]->mutex, i);
}
static void vhost_dev_unlock_vqs(struct vhost_dev *d)
{
int i = 0;
for (i = 0; i < d->nvqs; ++i)
mutex_unlock(&d->vqs[i]->mutex);
}
static int vhost_new_umem_range(struct vhost_umem *umem,
u64 start, u64 size, u64 end,
u64 userspace_addr, int perm)
@ -976,6 +987,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
int ret = 0;
mutex_lock(&dev->mutex);
vhost_dev_lock_vqs(dev);
switch (msg->type) {
case VHOST_IOTLB_UPDATE:
if (!dev->iotlb) {
@ -1009,6 +1021,7 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
break;
}
vhost_dev_unlock_vqs(dev);
mutex_unlock(&dev->mutex);
return ret;