> > > > > +int virtio_pmem_flush(struct nd_region *nd_region) > > > +{ > > > + int err; > > > + unsigned long flags; > > > + struct scatterlist *sgs[2], sg, ret; > > > + struct virtio_device *vdev = nd_region->provider_data; > > > + struct virtio_pmem *vpmem = vdev->priv; > > > + struct virtio_pmem_request *req; > > > + > > > + might_sleep(); > > > + req = kmalloc(sizeof(*req), GFP_KERNEL); > > > + if (!req) > > > + return -ENOMEM; > > > + > > > + req->done = req->wq_buf_avail = false; > > > + strcpy(req->name, "FLUSH"); > > > + init_waitqueue_head(&req->host_acked); > > > + init_waitqueue_head(&req->wq_buf); > > > + sg_init_one(&sg, req->name, strlen(req->name)); > > > + sgs[0] = &sg; > > > + sg_init_one(&ret, &req->ret, sizeof(req->ret)); > > > + sgs[1] = &ret; > > > + > > > + spin_lock_irqsave(&vpmem->pmem_lock, flags); > > > + err = virtqueue_add_sgs(vpmem->req_vq, sgs, 1, 1, req, GFP_ATOMIC); > > > + if (err) { > > > + dev_err(&vdev->dev, "failed to send command to virtio pmem device\n"); > > > + > > > + list_add_tail(&vpmem->req_list, &req->list); > > > + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); > > > + > > > + /* When host has read buffer, this completes via host_ack */ > > > + wait_event(req->wq_buf, req->wq_buf_avail); > > > + spin_lock_irqsave(&vpmem->pmem_lock, flags); > > > + } > > > > Aren't the arguments in `list_add_tail` swapped? The element we are adding > Yes, arguments for 'list_add_tail' should be swapped. list_add_tail(&req->list, &vpmem->req_list); Thank you, Pankaj