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Tue, 10 Dec 2019 09:05:49 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 2E04C11386A7; Tue, 10 Dec 2019 10:05:48 +0100 (CET) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v8 21/21] nbd: assert that Error** is not NULL in nbd_iter_channel_error References: <20191205174635.18758-1-vsementsov@virtuozzo.com> <20191205174635.18758-22-vsementsov@virtuozzo.com> <54278946-ad45-1a0d-e2b2-f96b86285c05@redhat.com> <8736dxcuo5.fsf@dusky.pond.sub.org> <6d55367c-42a3-3622-a483-d997b428796d@virtuozzo.com> Date: Tue, 10 Dec 2019 10:05:48 +0100 In-Reply-To: <6d55367c-42a3-3622-a483-d997b428796d@virtuozzo.com> (Vladimir Sementsov-Ogievskiy's message of "Fri, 6 Dec 2019 18:19:36 +0000") Message-ID: <87a780mtxv.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: hxgPu4UiM5WHqaIMzTg9wA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "qemu-devel@nongnu.org" , "qemu-block@nongnu.org" , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Vladimir Sementsov-Ogievskiy writes: > 06.12.2019 18:58, Markus Armbruster wrote: >> Eric Blake writes: >>=20 >>> On 12/5/19 11:46 AM, Vladimir Sementsov-Ogievskiy wrote: >>>> The local_err parameter is not here to return information about >>>> nbd_iter_channel_error failure. Instead it's assumed to be filled when >>>> passed to the function. This is already stressed by its name >>>> (local_err, instead of classic errp). Stress it additionally by >>>> assertion. >>>> >>>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>>> --- >>>> block/nbd.c | 1 + >>>> 1 file changed, 1 insertion(+) >>> >>> Our timing resulted in crossed mails - I was replying to v7 when this >>> landed, and my reply there is still relevant (namely, a better commit >>> message is needed, but the code gets my R-b with that change). >>=20 >> If v8 turns out to be fine except for commit message tweaks, I'll gladly >> to these in my tree. Just tell me what to do in a reply to this >> message. >>=20 > > Yes, this would be great, thanks! > > The only thing is your suggestion on patch 21, but it may be applied in s= eparate (and it's actually a separate thing) It's closer to idea than to suggestion, and it's separate. Commit message in my tree: nbd: assert that Error** is not NULL in nbd_iter_channel_error =20 All callers of nbd_iter_channel_error() pass the address of a local_err variable, and only call this function if an error has already occurred, using this function to propagate that error. This is already implied by its name (local_err instead of the classic errp), but it is worth additionally stressing this by adding an assertion to make it part of the function contract. =20 The local_err parameter is not here to return information about nbd_iter_channel_error failure. Instead it's assumed to be filled when passed to the function. This is already stressed by its name (local_err, instead of classic errp). Stress it additionally by assertion. Also: Reviewed-by: Markus Armbruster