Re: [Qemu-devel] [PATCH v2 2/4] 9pfs: introduce transport specific callbacks

[Greg Kurz <groug@kaod.org>]

On Mon, 28 Nov 2016 13:27:22 -0800
Stefano Stabellini <sstabellini@kernel.org> wrote:

> Don't call virtio functions from 9pfs generic code, use generic function
> callbacks instead.
> 
> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> 
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

> Changes in v2:
> - constify virtio_9p_transport and V9fsTransport
> - assert !s->transport.
> - code style
> ---
>  hw/9pfs/9p.c               |  8 ++++----
>  hw/9pfs/9p.h               | 19 +++++++++++++++++++
>  hw/9pfs/virtio-9p-device.c | 24 +++++++++++++++++-------
>  hw/9pfs/virtio-9p.h        |  9 ---------
>  4 files changed, 40 insertions(+), 20 deletions(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 05e950f..5a20a13 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -47,7 +47,7 @@ ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>      va_list ap;
>  
>      va_start(ap, fmt);
> -    ret = virtio_pdu_vmarshal(pdu, offset, fmt, ap);
> +    ret = pdu->s->transport->pdu_vmarshal(pdu, offset, fmt, ap);
>      va_end(ap);
>  
>      return ret;
> @@ -59,7 +59,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>      va_list ap;
>  
>      va_start(ap, fmt);
> -    ret = virtio_pdu_vunmarshal(pdu, offset, fmt, ap);
> +    ret = pdu->s->transport->pdu_vunmarshal(pdu, offset, fmt, ap);
>      va_end(ap);
>  
>      return ret;
> @@ -67,7 +67,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>  
>  static void pdu_push_and_notify(V9fsPDU *pdu)
>  {
> -    virtio_9p_push_and_notify(pdu);
> +    pdu->s->transport->push_and_notify(pdu);
>  }
>  
>  static int omode_to_uflags(int8_t mode)
> @@ -1751,7 +1751,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
>      struct iovec *iov;
>      unsigned int niov;
>  
> -    virtio_init_iov_from_pdu(pdu, &iov, &niov, is_write);
> +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
>  
>      qemu_iovec_init_external(&elem, iov, niov);
>      qemu_iovec_init(qiov, niov);
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index 07cee01..c8c9aa8 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -230,6 +230,7 @@ typedef struct V9fsState
>      enum p9_proto_version proto_version;
>      int32_t msize;
>      V9fsPDU pdus[MAX_REQ];
> +    const struct V9fsTransport *transport;
>      /*
>       * lock ensuring atomic path update
>       * on rename.
> @@ -343,4 +344,22 @@ void pdu_free(V9fsPDU *pdu);
>  void pdu_submit(V9fsPDU *pdu);
>  void v9fs_reset(V9fsState *s);
>  
> +struct V9fsTransport {
> +    ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt,
> +                                va_list ap);
> +    ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt,
> +                                  va_list ap);
> +    void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> +                                     unsigned int *pniov, bool is_write);
> +    void        (*push_and_notify)(V9fsPDU *pdu);
> +};
> +
> +static inline int v9fs_register_transport(V9fsState *s,
> +        const struct V9fsTransport *t)
> +{
> +    assert(!s->transport);
> +    s->transport = t;
> +    return 0;
> +}
> +
>  #endif
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 1782e4a..273425b 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -20,7 +20,9 @@
>  #include "hw/virtio/virtio-access.h"
>  #include "qemu/iov.h"
>  
> -void virtio_9p_push_and_notify(V9fsPDU *pdu)
> +static const struct V9fsTransport virtio_9p_transport;
> +
> +static void virtio_9p_push_and_notify(V9fsPDU *pdu)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> @@ -126,6 +128,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
>      v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
>      virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
>      v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
> +    v9fs_register_transport(s, &virtio_9p_transport);
>  
>  out:
>      return;
> @@ -148,8 +151,8 @@ static void virtio_9p_reset(VirtIODevice *vdev)
>      v9fs_reset(&v->state);
>  }
>  
> -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> -                            const char *fmt, va_list ap)
> +static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> +                                   const char *fmt, va_list ap)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> @@ -158,8 +161,8 @@ ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
>      return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
>  }
>  
> -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> -                              const char *fmt, va_list ap)
> +static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> +                                     const char *fmt, va_list ap)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> @@ -168,8 +171,8 @@ ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
>      return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
>  }
>  
> -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> -                              unsigned int *pniov, bool is_write)
> +static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> +                                     unsigned int *pniov, bool is_write)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> @@ -184,6 +187,13 @@ void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
>      }
>  }
>  
> +static const struct V9fsTransport virtio_9p_transport = {
> +    .pdu_vmarshal = virtio_pdu_vmarshal,
> +    .pdu_vunmarshal = virtio_pdu_vunmarshal,
> +    .init_iov_from_pdu = virtio_init_iov_from_pdu,
> +    .push_and_notify = virtio_9p_push_and_notify,
> +};
> +
>  /* virtio-9p device */
>  
>  static const VMStateDescription vmstate_virtio_9p = {
> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> index 52c4b9d..e763da2c 100644
> --- a/hw/9pfs/virtio-9p.h
> +++ b/hw/9pfs/virtio-9p.h
> @@ -14,15 +14,6 @@ typedef struct V9fsVirtioState
>      V9fsState state;
>  } V9fsVirtioState;
>  
> -void virtio_9p_push_and_notify(V9fsPDU *pdu);
> -
> -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> -                            const char *fmt, va_list ap);
> -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> -                              const char *fmt, va_list ap);
> -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> -                              unsigned int *pniov, bool is_write);
> -
>  #define TYPE_VIRTIO_9P "virtio-9p-device"
>  #define VIRTIO_9P(obj) \
>          OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)