Re: [Qemu-devel] [PATCH 1/2] virtio-scsi-dataplane: fix allocation for 'cmd_vrings'

[Kevin Wolf <kwolf@redhat.com>]

Am 10.11.2014 um 10:14 hat Ming Lei geschrieben:
> On Mon, Nov 10, 2014 at 4:24 PM, Markus Armbruster <armbru@redhat.com> wrote:
> > Ming Lei <ming.lei@canonical.com> writes:
> >
> >> The size of each element should be sizeof(VirtIOSCSIVring *).
> >>
> >> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> >> ---
> >>  hw/scsi/virtio-scsi-dataplane.c |    2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
> >> index 855439e..8a7cd9f 100644
> >> --- a/hw/scsi/virtio-scsi-dataplane.c
> >> +++ b/hw/scsi/virtio-scsi-dataplane.c
> >> @@ -239,7 +239,7 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
> >>      if (!s->event_vring) {
> >>          goto fail_vrings;
> >>      }
> >> -    s->cmd_vrings = g_malloc0(sizeof(VirtIOSCSIVring) * vs->conf.num_queues);
> >> +    s->cmd_vrings = g_malloc0(sizeof(VirtIOSCSIVring *) * vs->conf.num_queues);
> >>      for (i = 0; i < vs->conf.num_queues; i++) {
> >>          s->cmd_vrings[i] =
> >>              virtio_scsi_vring_init(s, vs->cmd_vqs[i],
> >
> > Please use something like
> >
> >     s->cmd_vrings = g_new0(VirtIOSCSIVring *, vs->conf.num_queues);
> >
> > This one crept in since I cleaned up g_malloc() use globally:
> 
> Your idea is good, but this one is a fix patch, and I
> think the g_new() conversion should be done in another
> patch since the two changes are different logically.

It's not really unrelated: g_new() would have caught the incorrect type
and made it a compiler error. So changing to g_new() in a patch fixing
such a bug is actually a logical conclusion and makes it more obvious
that your patch is correct.

Kevin