Re: [Qemu-devel] [PATCH v7 2/6] virtio-pmem: Add virtio pmem driver

Pankaj Gupta
2019-05-08T15:23:38Z

> >
> > > +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