Re: [Qemu-devel] [PATCH 1/2] migration/qemu-file: remove check on writev_buffer in qemu_put_compression_data

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: qemu-devel@nongnu.org, quintela@redhat.com
Subject: Re: [Qemu-devel] [PATCH 1/2] migration/qemu-file: remove check on writev_buffer in qemu_put_compression_data
Date: Fri, 23 Aug 2019 11:30:06 +0100	[thread overview]
Message-ID: <20190823103006.GE2784@work-vm> (raw)
In-Reply-To: <20190731144225.3784-2-richardw.yang@linux.intel.com>

* Wei Yang (richardw.yang@linux.intel.com) wrote:
> The check of writev_buffer is in qemu_fflush, which means it is not
> harmful if it is NULL.
> 
> And removing it will make the code consistent since all other
> add_to_iovec() is called without the check.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

So I think the real reason here is commit 11808bb  which removed
support for non-iovec writers.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/qemu-file.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 0431585502..35c22605dd 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -717,9 +717,7 @@ ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
>      }
>  
>      qemu_put_be32(f, blen);
> -    if (f->ops->writev_buffer) {
> -        add_to_iovec(f, f->buf + f->buf_index, blen, false);
> -    }
> +    add_to_iovec(f, f->buf + f->buf_index, blen, false);
>      f->buf_index += blen;
>      if (f->buf_index == IO_BUF_SIZE) {
>          qemu_fflush(f);
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK