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Re: [PATCH v3 06/44] qemu-option: Check return value instead of @err whe
From: |
Greg Kurz |
Subject: |
Re: [PATCH v3 06/44] qemu-option: Check return value instead of @err where convenient |
Date: |
Tue, 7 Jul 2020 10:25:28 +0200 |
On Mon, 06 Jul 2020 22:01:38 +0200
Markus Armbruster <armbru@redhat.com> wrote:
> Greg Kurz <groug@kaod.org> writes:
>
> > On Mon, 6 Jul 2020 10:09:12 +0200
> > Markus Armbruster <armbru@redhat.com> wrote:
> >
> >> Convert uses like
> >>
> >> opts = qemu_opts_create(..., &err);
> >> if (err) {
> >> ...
> >> }
> >>
> >> to
> >>
> >> opts = qemu_opts_create(..., &err);
> >
> > The patch doesn't strictly do that since it also converts &err to errp.
>
> Yes, and that's actually why I do it. I'll change the commit message to
> say so:
>
> to
>
> opts = qemu_opts_create(..., errp);
>
Ok.
> > This is okay because most of the changes also drop the associated
> > error_propagate(), with the exception of block/parallels.c for which
> > I had to check how local_err is used. As already noted by Vladimir
> > earlier this generates an harmless "no-op error_propagate", but it
> > could be worth mentioning that in the changelog for future reviews :)
>
> Yes, error_propagate() becomes a no-op for one out of three error paths
> through it. There's similar "partial no-opification" elsewhere in this
> series, notably in PATCH 36.
>
> Concrete suggestions for improving the commit message further are
> welcome!
>
What about this ?
The change in block/parallels.c doesn't provide any clue on the usage
of local_err. As usual it is expected to be equal to NULL at the time
qemu_opts_create() is called, and the goto on the error path jumps
here:
fail_options:
error_propagate(errp, local_err);
So, if qemu_opts_create() fails, we end up doing error_propagate(errp, NULL)
which is a harmles no-op.
> >> if (!opts) {
> >> ...
> >> }
> >>
> >> Eliminate error_propagate() that are now unnecessary. Delete @err
> >> that are now unused.
> >>
> >> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> >> Reviewed-by: Eric Blake <eblake@redhat.com>
> >> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> >> ---
> >> block/parallels.c | 4 ++--
> >> blockdev.c | 5 ++---
> >> qdev-monitor.c | 5 ++---
> >> util/qemu-config.c | 10 ++++------
> >> util/qemu-option.c | 12 ++++--------
> >
> > Maybe some other potential candidates ?
> >
> > chardev/char.c:
> >
> > opts = qemu_opts_create(qemu_find_opts("chardev"), label, 1, &local_err);
> > if (local_err) {
> > error_report_err(local_err);
> > return NULL;
> > }
> >
> > monitor/hmp-cmds.c:
> >
> > opts = qemu_opts_from_qdict(qemu_find_opts("netdev"), qdict, &err);
> > if (err) {
> > goto out;
> > }
> >
> >
> > opts = qemu_opts_from_qdict(qemu_find_opts("object"), qdict, &err);
> > if (err) {
> > goto end;
> > }
>
> Don't fit my clarified commit message, because I can't replace &err by
> errp there.
>
Sure.
> I found these:
>
> diff --git a/block/blkdebug.c b/block/blkdebug.c
> index 7194bc7f06..471b597dfe 100644
> --- a/block/blkdebug.c
> +++ b/block/blkdebug.c
> @@ -294,17 +294,13 @@ static int read_config(BDRVBlkdebugState *s, const
> char *filename,
>
> d.s = s;
> d.action = ACTION_INJECT_ERROR;
> - qemu_opts_foreach(&inject_error_opts, add_rule, &d, &local_err);
> - if (local_err) {
> - error_propagate(errp, local_err);
> + if (qemu_opts_foreach(&inject_error_opts, add_rule, &d, errp)) {
> ret = -EINVAL;
> goto fail;
> }
>
> d.action = ACTION_SET_STATE;
> - qemu_opts_foreach(&set_state_opts, add_rule, &d, &local_err);
> - if (local_err) {
> - error_propagate(errp, local_err);
> + if (qemu_opts_foreach(&set_state_opts, add_rule, &d, errp)) {
> ret = -EINVAL;
> goto fail;
> }
>
> However, I really need to get a pull request out... Can patch them
> later.
>
Yeah and we might probably find a few more, but certainly not much
after this colossal effort of yours.
> > With or without the extra changes:
> >
> > Reviewed-by: Greg Kurz <groug@kaod.org>
>
> Thanks!
>
My pleasure.
- [PATCH v3 02/44] error: Document Error API usage rules, (continued)
- [PATCH v3 02/44] error: Document Error API usage rules, Markus Armbruster, 2020/07/06
- [PATCH v3 15/44] hmp: Eliminate a variable in hmp_migrate_set_parameter(), Markus Armbruster, 2020/07/06
- [PATCH v3 08/44] qemu-option: Factor out helper find_default_by_name(), Markus Armbruster, 2020/07/06
- [PATCH v3 22/44] qom: Crash more nicely on object_property_get_link() failure, Markus Armbruster, 2020/07/06
- [PATCH v3 21/44] qom: Rename qdev_get_type() to object_get_type(), Markus Armbruster, 2020/07/06
- [PATCH v3 10/44] qemu-option: Factor out helper opt_create(), Markus Armbruster, 2020/07/06
- [PATCH v3 06/44] qemu-option: Check return value instead of @err where convenient, Markus Armbruster, 2020/07/06
- [PATCH v3 03/44] qdev: Use returned bool to check for qdev_realize() etc. failure, Markus Armbruster, 2020/07/06
[PATCH v3 18/44] qapi: Use returned bool to check for failure, manual part, Markus Armbruster, 2020/07/06
[PATCH v3 30/44] qdev: Make functions taking Error ** return bool, not void, Markus Armbruster, 2020/07/06
[PATCH v3 13/44] qemu-option: Use returned bool to check for failure, Markus Armbruster, 2020/07/06
[PATCH v3 17/44] qapi: Use returned bool to check for failure, Coccinelle part, Markus Armbruster, 2020/07/06
[PATCH v3 40/44] qapi: Purge error_propagate() from QAPI core, Markus Armbruster, 2020/07/06