On 2024/1/6 0:06, Alexander H Duyck wrote: >> >> static void handle_tx_copy(struct vhost_net *net, struct socket *sock) >> @@ -1353,8 +1318,7 @@ static int vhost_net_open(struct inode *inode, struct file *f) >> vqs[VHOST_NET_VQ_RX]); >> >> f->private_data = n; >> - n->page_frag.page = NULL; >> - n->refcnt_bias = 0; >> + n->pf_cache.va = NULL; >> >> return 0; >> } >> @@ -1422,8 +1386,9 @@ static int vhost_net_release(struct inode *inode, struct file *f) >> kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); >> kfree(n->vqs[VHOST_NET_VQ_TX].xdp); >> kfree(n->dev.vqs); >> - if (n->page_frag.page) >> - __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias); >> + if (n->pf_cache.va) >> + __page_frag_cache_drain(virt_to_head_page(n->pf_cache.va), >> + n->pf_cache.pagecnt_bias); >> kvfree(n); >> return 0; >> } > > I would recommend reordering this patch with patch 5. Then you could > remove the block that is setting "n->pf_cache.va = NULL" above and just > make use of page_frag_cache_drain in the lower block which would also > return the va to NULL. I am not sure if we can as there is no zeroing for 'struct vhost_net' in vhost_net_open(). If we don't have "n->pf_cache.va = NULL", don't we use the uninitialized data when calling page_frag_alloc_align() for the first time? > . >
