Re: [Qemu-devel] [PATCH 4/4] migration: simplify writev vs. non-writev logic

[Juan Quintela <quintela@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> wrote:
> Check f->iovcnt in add_to_iovec, f->buf_index in qemu_put_buffer/byte.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  savevm.c | 22 +++++++++-------------
>  1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/savevm.c b/savevm.c
> index a2f6bc0..63f4c82 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -626,7 +626,7 @@ static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size)
>          f->iov[f->iovcnt++].iov_len = size;
>      }
>  
> -    if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
> +    if (f->iovcnt >= MAX_IOV_SIZE) {
>          qemu_fflush(f);
>      }
>  }
> @@ -662,12 +662,10 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
>          f->bytes_xfer += size;
>          if (f->ops->writev_buffer) {
>              add_to_iovec(f, f->buf + f->buf_index, l);
> -            f->buf_index += l;
> -        } else {
> -            f->buf_index += l;
> -            if (f->buf_index == IO_BUF_SIZE) {
> -                qemu_fflush(f);
> -            }
> +        }
> +        f->buf_index += l;
> +        if (f->buf_index == IO_BUF_SIZE) {
> +            qemu_fflush(f);
>          }
>          if (qemu_file_get_error(f)) {
>              break;
> @@ -687,12 +685,10 @@ void qemu_put_byte(QEMUFile *f, int v)
>      f->bytes_xfer++;
>      if (f->ops->writev_buffer) {
>          add_to_iovec(f, f->buf + f->buf_index, 1);
> -        f->buf_index++;
> -    } else {
> -        f->buf_index++;
> -        if (f->buf_index == IO_BUF_SIZE) {
> -            qemu_fflush(f);
> -        }
> +    }
> +    f->buf_index++;
> +    if (f->buf_index == IO_BUF_SIZE) {
> +        qemu_fflush(f);
>      }
>  }

If you follow my advice of moving the call to add_to_iovec() you get
this one simplified and only one place to do this.

Thanks,  Juan.