On Mon, Dec 19, 2016 at 04:51:23PM +0800, Dou Liyang wrote: > make the bdrv_next_node() clearly and add some comments. > > Signed-off-by: Dou Liyang <douly.f...@cn.fujitsu.com> > --- > block.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/block.c b/block.c > index 39ddea3..01c9e51 100644 > --- a/block.c > +++ b/block.c > @@ -2931,12 +2931,20 @@ bool bdrv_chain_contains(BlockDriverState *top, > BlockDriverState *base) > return top != NULL; > } > > +/* > + * Return the BlockDriverStates of all the named nodes.
This sentence describes how this function is used in a loop. The
semantics of one call to this function are different: only a *single*
named node's BlockDriverState is returned.
> + * If @bs is null, return the first one.
> + * Else, return @bs's next sibling, which may be null.
> + *
> + * To iterate over all BlockDriverStates, do
> + * for (bs = bdrv_next_node(NULL); bs; bs = bdrv_next_node(blk)) {
> + * ...
> + * }
> + */
> BlockDriverState *bdrv_next_node(BlockDriverState *bs)
> {
> - if (!bs) {
> - return QTAILQ_FIRST(&graph_bdrv_states);
> - }
> - return QTAILQ_NEXT(bs, node_list);
> + return bs ? QTAILQ_NEXT(bs, node_list)
> + : QTAILQ_FIRST(&graph_bdrv_states);
The conditional operator (?:) is often considered harder to read than an
if statement. I see no reason to modify the code.
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