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Re: [PATCH v11 7/8] nbd: introduce ERRP_AUTO_PROPAGATE
From: |
Markus Armbruster |
Subject: |
Re: [PATCH v11 7/8] nbd: introduce ERRP_AUTO_PROPAGATE |
Date: |
Tue, 07 Jul 2020 13:51:02 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) |
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> writes:
> If we want to add some info to errp (by error_prepend() or
> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
> Otherwise, this info will not be added when errp == &error_fatal
Same for &error_abort, but to fix that, ERRP_AUTO_PROPAGATE() would have
to compromise stack backtraces, so it doesn't.
> (the program will exit prior to the error_append_hint() or
> error_prepend() call). Fix such cases.
Unclear what exactly is being fixed here, if anything. What are the
cases? Can they happen?
The following look like possible cases: nbd_read(),
nbd_send_option_request(), nbd_handle_reply_err(), nbd_opt_info_or_go(),
nbd_start_negotiate(), nbd_receive_negotiate(),
nbd_negotiate_send_rep_verr(), nbd_negotiate_send_rep_list(),
nbd_negotiate_handle_export_name(), nbd_negotiate(),
nbd_export_remove().
Additionally in PATCH 6, v9fs_device_realize_common().
Nothing in PATCH 3+4+5+8 as far as I can tell.
If we lack the time to provide a complete assessment in the commit
messages, let's say so there.
> If we want to check error after errp-function call, we need to
> introduce local_err and then propagate it to errp. Instead, use
> ERRP_AUTO_PROPAGATE macro, benefits are:
> 1. No need of explicit error_propagate call
> 2. No need of explicit local_err variable: use errp directly
> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
> &error_fatal, this means that we don't break error_abort
> (we'll abort on error_set, not on error_propagate)
Direct use of @errp improves behavior when the argument is
&error_abort. Worth mentioning, I think.
>
> This commit is generated by command
>
> sed -n '/^Network Block Device (NBD)$/,/^$/{s/^F: //p}' \
> MAINTAINERS | \
> xargs git ls-files | grep '\.[hc]$' | \
> xargs spatch \
> --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
> --macro-file scripts/cocci-macro-file.h \
> --in-place --no-show-diff --max-width 80
>
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Reported-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
- [PATCH v11 0/8] error: auto propagated local_err part I, Vladimir Sementsov-Ogievskiy, 2020/07/03
- [PATCH v11 1/8] error: auto propagated local_err, Vladimir Sementsov-Ogievskiy, 2020/07/03
- [PATCH v11 2/8] scripts: Coccinelle script to use ERRP_AUTO_PROPAGATE(), Vladimir Sementsov-Ogievskiy, 2020/07/03
- [PATCH v11 4/8] pflash: introduce ERRP_AUTO_PROPAGATE, Vladimir Sementsov-Ogievskiy, 2020/07/03
- [PATCH v11 7/8] nbd: introduce ERRP_AUTO_PROPAGATE, Vladimir Sementsov-Ogievskiy, 2020/07/03
- [PATCH v11 8/8] xen: introduce ERRP_AUTO_PROPAGATE, Vladimir Sementsov-Ogievskiy, 2020/07/03