On 01.07.2011, at 09:42, Hannes Reinecke wrote:
> Occasionally, the buffer needs to be placed at a offset within
> the iovec when copying the buffer to the iovec.
So this is a buffer into the iovec, right? Wouldn't it make sense to also modify iov_to_buf respectively then, so the API stays similar? Also, it'd be nice to give the parameter a more obvious name, so potential users can easily recognize what it offsets.
Alex
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> ---
> hw/virtio-net.c | 2 +-
> hw/virtio-serial-bus.c | 2 +-
> iov.c | 23 ++++++++++++++---------
> iov.h | 2 +-
> 4 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 6997e02..a32cc01 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -657,7 +657,7 @@ static ssize_t virtio_net_receive(VLANClientState *nc, const uint8_t *buf, size_
>
> /* copy in packet. ugh */
> len = iov_from_buf(sg, elem.in_num,
> - buf + offset, size - offset);
> + buf + offset, 0, size - offset);
> total += len;
> offset += len;
> /* If buffers can't be merged, at this point we
> diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
> index 7f6db7b..53c58d0 100644
> --- a/hw/virtio-serial-bus.c
> +++ b/hw/virtio-serial-bus.c
> @@ -103,7 +103,7 @@ static size_t write_to_port(VirtIOSerialPort *port,
> }
>
> len = iov_from_buf(elem.in_sg, elem.in_num,
> - buf + offset, size - offset);
> + buf + offset, 0, size - offset);
> offset += len;
>
> virtqueue_push(vq, &elem, len);
> diff --git a/iov.c b/iov.c
> index 588cd04..9ead6ee 100644
> --- a/iov.c
> +++ b/iov.c
> @@ -15,21 +15,26 @@
> #include "iov.h"
>
> size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
> - const void *buf, size_t size)
> + const void *buf, size_t offset, size_t size)
> {
> - size_t offset;
> + size_t iov_off, buf_off;
> unsigned int i;
>
> - offset = 0;
> - for (i = 0; offset < size && i < iovcnt; i++) {
> - size_t len;
> + iov_off = 0;
> + buf_off = 0;
> + for (i = 0; i < iovcnt && size; i++) {
> + if (offset < (iov_off + iov[i].iov_len)) {
> + size_t len = MIN((iov_off + iov[i].iov_len) - offset, size);
>
> - len = MIN(iov[i].iov_len, size - offset);
> + memcpy(iov[i].iov_base + (offset - iov_off), buf + buf_off, len);
>
> - memcpy(iov[i].iov_base, buf + offset, len);
> - offset += len;
> + buf_off += len;
> + offset += len;
> + size -= len;
> + }
> + iov_off += iov[i].iov_len;
> }
> - return offset;
> + return buf_off;
> }
>
> size_t iov_to_buf(const struct iovec *iov, const unsigned int iovcnt,
> diff --git a/iov.h b/iov.h
> index 60a8547..2677527 100644
> --- a/iov.h
> +++ b/iov.h
> @@ -13,7 +13,7 @@
> #include "qemu-common.h"
>
> size_t iov_from_buf(struct iovec *iov, unsigned int iovcnt,
> - const void *buf, size_t size);
> + const void *buf, size_t offset, size_t size);
> size_t iov_to_buf(const struct iovec *iov, const unsigned int iovcnt,
> void *buf, size_t offset, size_t size);
> size_t iov_size(const struct iovec *iov, const unsigned int iovcnt);
> --
> 1.6.0.2
>
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