Re: [Qemu-devel] [PATCH 1/2] QEMUSizedBuffer: only free qsb that qemu_bufopen allocated

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Yang Hongyang (yanghy@cn.fujitsu.com) wrote:
> Only free qsb that qemu_bufopen allocated, and also allow
> qemu_bufopen accept qsb as input for write operation. It
> will make the API more logical:
> 1.If you create the QEMUSizedBuffer yourself, you need to
>   free it by using qsb_free() but not depends on other API
>   like qemu_fclose.
> 2.allow qemu_bufopen() accept QEMUSizedBuffer as input for
>   write operation, otherwise, it will be a little strange
>   for this API won't accept the second parameter.
> 
> This brings API change, since there are only 3
> users of this API currently, this change only impact the
> first one which will be fixed in patch 2 of this patchset,
> so I think it is safe to do this change.
> 
> 1     70  tests/test-vmstate.c <<open_mem_file_read>>
>             return qemu_bufopen("r", qsb);
> 2    404  tests/test-vmstate.c <<test_save_noskip>>
>             QEMUFile *fsave = qemu_bufopen("w", NULL);
> 3    424  tests/test-vmstate.c <<test_save_skip>>
>             QEMUFile *fsave = qemu_bufopen("w", NULL);
> 
> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Juan Quintela <quintela@redhat.com>

Yes, this feels cleaner to me.

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

Dave


> ---
>  qemu-file.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/qemu-file.c b/qemu-file.c
> index f938e36..52f8d69 100644
> --- a/qemu-file.c
> +++ b/qemu-file.c
> @@ -904,6 +904,7 @@ QEMUSizedBuffer *qsb_clone(const QEMUSizedBuffer *qsb)
>  typedef struct QEMUBuffer {
>      QEMUSizedBuffer *qsb;
>      QEMUFile *file;
> +    bool qsb_allocated;
>  } QEMUBuffer;
>  
>  static int buf_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
> @@ -933,7 +934,9 @@ static int buf_close(void *opaque)
>  {
>      QEMUBuffer *s = opaque;
>  
> -    qsb_free(s->qsb);
> +    if (s->qsb_allocated) {
> +        qsb_free(s->qsb);
> +    }
>  
>      g_free(s);
>  
> @@ -972,12 +975,11 @@ QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input)
>      }
>  
>      s = g_malloc0(sizeof(QEMUBuffer));
> -    if (mode[0] == 'r') {
> -        s->qsb = input;
> -    }
> +    s->qsb = input;
>  
>      if (s->qsb == NULL) {
>          s->qsb = qsb_create(NULL, 0);
> +        s->qsb_allocated = true;
>      }
>      if (!s->qsb) {
>          g_free(s);
> -- 
> 1.9.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK