Re: [PATCH] contrib/vhost-user-blk: Clean up deallocation of VuVirtqElement

[Raphael Norwitz <raphael.norwitz@nutanix.com>]

On Thu, Jun 30, 2022 at 10:52:19AM +0200, Markus Armbruster wrote:
> We allocate VuVirtqElement with g_malloc() in
> virtqueue_alloc_element(), but free it with free() in
> vhost-user-blk.c.  Harmless, but use g_free() anyway.
> 
> One of the calls is guarded by a "not null" condition.  Useless,
> because it cannot be null (it's dereferenced right before), and even

NIT: if it

> it it could be, free() and g_free() do the right thing.  Drop the
> conditional.
> 

Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>

> Fixes: Coverity CID 1490290
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
> Not even compile-tested, because I can't figure out how this thing is
> supposed to be built.  Its initial commit message says "make
> vhost-user-blk", but that doesn't work anymore.
> 

make contrib/vhost-user-blk/vhost-user-blk works for me.

>  contrib/vhost-user-blk/vhost-user-blk.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/contrib/vhost-user-blk/vhost-user-blk.c b/contrib/vhost-user-blk/vhost-user-blk.c
> index 9cb78ca1d0..d6932a2645 100644
> --- a/contrib/vhost-user-blk/vhost-user-blk.c
> +++ b/contrib/vhost-user-blk/vhost-user-blk.c
> @@ -106,10 +106,7 @@ static void vub_req_complete(VubReq *req)
>                    req->size + 1);
>      vu_queue_notify(vu_dev, req->vq);
>  
> -    if (req->elem) {
> -        free(req->elem);
> -    }
> -
> +    g_free(req->elem);
>      g_free(req);
>  }
>  
> @@ -243,7 +240,7 @@ static int vub_virtio_process_req(VubDev *vdev_blk,
>      /* refer to hw/block/virtio_blk.c */
>      if (elem->out_num < 1 || elem->in_num < 1) {
>          fprintf(stderr, "virtio-blk request missing headers\n");
> -        free(elem);
> +        g_free(elem);
>          return -1;
>      }
>  
> @@ -325,7 +322,7 @@ static int vub_virtio_process_req(VubDev *vdev_blk,
>      return 0;
>  
>  err:
> -    free(elem);
> +    g_free(elem);
>      g_free(req);
>      return -1;
>  }
> -- 
> 2.35.3
>