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.