The Thursday 11 Sep 2014 à 07:00:41 (-0600), Eric Blake wrote :
> On 09/11/2014 05:34 AM, Benoît Canet wrote:
> > The Wednesday 10 Sep 2014 à 10:13:37 (+0200), Markus Armbruster wrote :
> >> device_name[] is can become non-empty only in bdrv_new_named() and
> >> bdrv_move_feature_fields(). The latter is used only to undo damage
> >> done by bdrv_swap(). The former is called only by blk_new_with_bs().
> >> Therefore, when a BlockDriverState's device_name[] is non-empty, then
> >> it's owned by a BlockBackend.
>
> [lots of lines trimmed - it's not only okay, but desirable to trim out
> portions of a patch that you are okay with, in order to call attention
> to the problem spots that you are commenting on without making the
> reader have to scroll through pages of quoted context]
>
> >>
> >> -const char *bdrv_get_device_name(BlockDriverState *bs)
> >> +const char *bdrv_get_device_name(const BlockDriverState *bs)
> >> {
> >> - return bs->device_name;
> >> + const char *name = bs->blk ? blk_name(bs->blk) : NULL;
> >> + return name ?: "";
> >> }
> >
> > Why not ?
> >
> > return bs->blk ? blk_name(bs->blk) : "";
>
> If I understand right, it was because blk_name(bs->blk) may return NULL,
It think it can't: see patch 2 extract:
> +BlockBackend *blk_new(const char *name, Error **errp)
> +{
> + BlockBackend *blk = g_new0(BlockBackend, 1);
> +
> + assert(name && name[0]);
> but this function is guaranteed to return non-NULL.
