On Mon, 21 Nov 2016 13:39:32 -0800
Stefano Stabellini <sstabell...@kernel.org> wrote:
> Not all 9pfs transports share memory between request and response. For
> those who don't, it is necessary to know how much memory is required in
> the response.
>
> Signed-off-by: Stefano Stabellini <sstabell...@kernel.org>
> ---
IIUC the transport used in Xen requires you pass the size when sending a
P9_RREAD message back to the guest, i.e. only in the case when is_write is
false, correct ?
If so, for better clarity, what about having two distinct init_in_iov_from_pdu
and init_out_iov_from_pdu ops, with an explicit comment in the virtio-9p
implementation of init_in_iov_from_pdu so that someone isn't tempted to drop
the apparently unused size argument ? Would this be ok for you on the Xen
side ?
Cheers.
--
Greg
> hw/9pfs/9p.c | 2 +-
> hw/9pfs/9p.h | 2 +-
> hw/9pfs/virtio-9p-device.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index b6ec042..b82212b 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -1652,7 +1652,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov,
> V9fsPDU *pdu,
> struct iovec *iov;
> unsigned int niov;
>
> - pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> + pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write, skip +
> size);
>
> 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 ab398d0..c830188 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -348,7 +348,7 @@ 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);
> + unsigned int *pniov, bool is_write, size_t
> size);
> void (*push_and_notify)(V9fsPDU *pdu);
> };
>
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index e1a37a4..e2b27e8 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -172,7 +172,7 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t
> offset,
> }
>
> static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> - unsigned int *pniov, bool is_write)
> + unsigned int *pniov, bool is_write, size_t
> size)
> {
> V9fsState *s = pdu->s;
> V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
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