On Fri, Jul 13, 2018 at 01:22:31PM +0530, Pankaj Gupta wrote:
> + /* The request submission function */
> +static int virtio_pmem_flush(struct device *dev)
> +{
> + int err;
> + unsigned long flags;
> + struct scatterlist *sgs[2], sg, ret;
> + struct virtio_device *vdev = dev_to_virtio(dev->parent->parent);
> + struct virtio_pmem *vpmem = vdev->priv;
> + struct virtio_pmem_request *req = kmalloc(sizeof(*req), GFP_KERNEL);
> +
> + req->done = false;
> + init_waitqueue_head(&req->acked);
> + spin_lock_irqsave(&vpmem->pmem_lock, flags);
> +
> + sg_init_one(&sg, req, sizeof(req));
What are you trying to do here?
sizeof(req) == sizeof(struct virtio_pmem_request *) == sizeof(void *)
Did you mean sizeof(*req)?
But why map struct virtio_pmem_request to the device? struct
virtio_pmem_request is the driver-internal request state and is not part
of the hardware interface.
> + sgs[0] = &sg;
> + sg_init_one(&ret, &req->ret, sizeof(req->ret));
> + sgs[1] = &ret;
> + 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");
This can happen if the virtqueue is full. Printing a message and
failing the flush isn't appropriate. This thread needs to wait until
virtqueue space becomes available.
> + spin_unlock_irqrestore(&vpmem->pmem_lock, flags);
> + return -ENOSPC;
req is leaked.
> + virtio_device_ready(vdev);
This call isn't needed. Driver use it when they wish to submit buffers
on virtqueues before ->probe() returns.
> diff --git a/include/linux/virtio_pmem.h b/include/linux/virtio_pmem.h
> new file mode 100644
> index 0000000..0f83d9c
> --- /dev/null
> +++ b/include/linux/virtio_pmem.h
include/ is for declarations (e.g. kernel APIs) needed by other
compilation units. The contents of this header are internal to the
virtio_pmem driver implementation and can therefore be in virtio_pmem.c.
include/linux/virtio_pmem.h isn't necessary since nothing besides
virtio_pmem.c will need to include it.
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