Re: [Qemu-trivial] [PATCH] dma-helpers: avoid calling dma_bdrv_unmap() twice

[Michael Tokarev <mjt@tls.msk.ru>]

23.05.2014 07:44, Jules Wang wrote:
> Calling dma_bdrv_unmap() twice is not necessary and may cause
> potential problems if some code changes.
> 
> Signed-off-by: Jules Wang <junqing.wang@cs2c.com.cn>
> ---
>  dma-helpers.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/dma-helpers.c b/dma-helpers.c
> index 5f421e9..53cbe92 100644
> --- a/dma-helpers.c
> +++ b/dma-helpers.c
> @@ -143,12 +143,12 @@ static void dma_bdrv_cb(void *opaque, int ret)
>  
>      dbs->acb = NULL;
>      dbs->sector_num += dbs->iov.size / 512;
> -    dma_bdrv_unmap(dbs);
>  
>      if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
>          dma_complete(dbs, ret);
>          return;
>      }
> +    dma_bdrv_unmap(dbs);
>  
>      while (dbs->sg_cur_index < dbs->sg->nsg) {
>          cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;

Applied to -trivial!

Maybe not-so-trivial, as I had to look at dma_complete() (who calls
dma_bdrv_unmap() ofcourse) to understand what's going on :)

Thank you!

/mjt