From: Eric Blake <eblake@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, armbru@redhat.com, dgilbert@redhat.com
Subject: Re: [Qemu-devel] [PATCH v2 1/3] error: don't rely on pointer comparisons
Date: Wed, 17 Jun 2015 09:41:19 -0600 [thread overview]
Message-ID: <5581951F.9050802@redhat.com> (raw)
In-Reply-To: <1434525861-21768-2-git-send-email-mst@redhat.com>
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On 06/17/2015 01:24 AM, Michael S. Tsirkin wrote:
> makes it possible to copy error_abort pointers,
> not just pass them on directly.
>
> @@ -168,7 +175,7 @@ void error_free(Error *err)
>
> void error_propagate(Error **dst_errp, Error *local_err)
> {
> - if (local_err && dst_errp == &error_abort) {
> + if (local_err && error_is_abort(dst_errp)) {
> error_report_err(local_err);
> abort();
> } else if (dst_errp && !*dst_errp) {
As I pointed out on 3/3, this breaks code that does:
if (local_err) {
error_propagate(errp, local_err);
...
}
now that local_err is non-NULL when errp is error_abort. But what if
you alter the semantics, and have error_propagate return a bool (true if
an error was propagated, false if no error or caller didn't care):
bool error_propagate(Error **dst_errp, Error *local_err)
{
if (error_is_abort(&local_err)) {
assert(error_is_abort(dst_errp);
return false;
}
if (local_err && error_is_abort(dst_errp)) {
error_report_err(local_err);
abort();
}
if (dst_errp && !*dst_errp) {
*dst_errp = local_err;
return true;
}
if (local_err) {
error_free(local_err);
}
return false;
}
then callers can be modified to this idiom (also has the benefit of
being one line shorter):
if (error_propagate(errp, local_err)) {
...
}
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2015-06-17 15:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 7:24 [Qemu-devel] [PATCH v2 0/3] error: allow local errors to trigger abort Michael S. Tsirkin
2015-06-17 7:24 ` [Qemu-devel] [PATCH v2 1/3] error: don't rely on pointer comparisons Michael S. Tsirkin
2015-06-17 15:21 ` Eric Blake
2015-06-17 15:41 ` Eric Blake [this message]
2015-06-18 15:36 ` Markus Armbruster
2015-06-18 16:10 ` Markus Armbruster
2015-06-17 7:24 ` [Qemu-devel] [PATCH v2 2/3] error: allow local errors to trigger abort Michael S. Tsirkin
2015-06-17 7:24 ` [Qemu-devel] [PATCH v2 3/3] block/nfs: switch to error_init_local Michael S. Tsirkin
2015-06-17 15:32 ` Eric Blake
2015-06-23 9:03 ` Michael S. Tsirkin
2015-06-18 16:34 ` [Qemu-devel] [PATCH v2 0/3] error: allow local errors to trigger abort Markus Armbruster
2015-06-18 16:49 ` Paolo Bonzini
2015-06-22 11:31 ` Markus Armbruster
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