Re: [Qemu-devel] [PATCH 02/17] block: Pass local error object pointer to error_append_hint()

From: Kevin Wolf <kwolf@redhat.com>
To: John Snow <jsnow@redhat.com>
Cc: "Fam Zheng" <fam@euphon.net>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Jeff Cody" <codyprime@gmail.com>,
	"Mark Cave-Ayland" <mark.cave-ayland@ilande.co.uk>,
	qemu-devel@nongnu.org, "Michael Roth" <mdroth@linux.vnet.ibm.com>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	"Subbaraya Sundeep" <sundeep.lkml@gmail.com>,
	qemu-block@nongnu.org, "Juan Quintela" <quintela@redhat.com>,
	"David Hildenbrand" <david@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Halil Pasic" <pasic@linux.ibm.com>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Eric Farman" <farman@linux.ibm.com>,
	"Greg Kurz" <groug@kaod.org>,
	"Yuval Shaia" <yuval.shaia@oracle.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	qemu-arm@nongnu.org, "Richard Henderson" <rth@twiddle.net>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Cornelia Huck" <cohuck@redhat.com>,
	qemu-s390x@nongnu.org, "Max Reitz" <mreitz@redhat.com>,
	qemu-ppc@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 02/17] block: Pass local error object pointer to error_append_hint()
Date: Wed, 18 Sep 2019 09:33:12 +0200	[thread overview]
Message-ID: <20190918073312.GA5207@localhost.localdomain> (raw)
In-Reply-To: <8cbb8459-a4bb-2efc-c9f8-d9e95230b3ac@redhat.com>

Am 17.09.2019 um 21:10 hat John Snow geschrieben:
> 
> 
> On 9/17/19 10:46 AM, Kevin Wolf wrote:
> > Am 17.09.2019 um 16:39 hat Eric Blake geschrieben:
> >> On 9/17/19 5:20 AM, Greg Kurz wrote:
> >>> Ensure that hints are added even if errp is &error_fatal or &error_abort.
> >>>
> >>> Signed-off-by: Greg Kurz <groug@kaod.org>
> >>> ---
> >>>  block/backup.c       |    7 +++++--
> >>>  block/dirty-bitmap.c |    7 +++++--
> >>>  block/file-posix.c   |   20 +++++++++++++-------
> >>>  block/gluster.c      |   23 +++++++++++++++--------
> >>>  block/qcow.c         |   10 ++++++----
> >>>  block/qcow2.c        |    7 +++++--
> >>>  block/vhdx-log.c     |    7 +++++--
> >>>  block/vpc.c          |    7 +++++--
> >>>  8 files changed, 59 insertions(+), 29 deletions(-)
> >>>
> >>> diff --git a/block/backup.c b/block/backup.c
> >>> index 763f0d7ff6db..d8c422a0e3bc 100644
> >>> --- a/block/backup.c
> >>> +++ b/block/backup.c
> >>> @@ -602,11 +602,14 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target,
> >>>                      BACKUP_CLUSTER_SIZE_DEFAULT);
> >>>          return BACKUP_CLUSTER_SIZE_DEFAULT;
> >>>      } else if (ret < 0 && !target->backing) {
> >>> -        error_setg_errno(errp, -ret,
> >>> +        Error *local_err = NULL;
> >>
> >> Can we go with the shorter name 'err' instead of 'local_err'?  I know,
> >> we aren't consistent (both styles appear throughout the tree), but the
> >> shorter style is more appealing to me.
> > 
> > I like local_err better because it's easier to distinguish from errp.
> > The compiler might catch it if you use the wrong one because one is
> > Error* and the other is Error**, but as a reviewer, I can still get
> > confused.
> 
> Doesn't that sound like a striking reason for condemnation of this
> entire model?

Might be, but do you have a better idea?

Kevin