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Thu, 16 Sep 2021 08:02:54 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 6D41A13A23; Thu, 16 Sep 2021 08:02:54 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 1penFy76QmHIJgAAMHmgww (envelope-from ); Thu, 16 Sep 2021 08:02:54 +0000 Message-ID: From: Martin Wilck To: Benjamin Marzinski Date: Thu, 16 Sep 2021 10:02:53 +0200 In-Reply-To: <20210916033237.GP3087@octiron.msp.redhat.com> References: <20210910114120.13665-1-mwilck@suse.com> <20210910114120.13665-31-mwilck@suse.com> <20210916033237.GP3087@octiron.msp.redhat.com> User-Agent: Evolution 3.40.4 MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-MIME-Autoconverted: from quoted-printable to 8bit by lists01.pubmisc.prod.ext.phx2.redhat.com id 18G833wv020612 X-loop: dm-devel@redhat.com Cc: lixiaokeng@huawei.com, dm-devel@redhat.com, Chongyun Wu Subject: Re: [dm-devel] [PATCH 30/35] multipathd: uxlsnr: merge uxsock_trigger() into state machine X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable On Wed, 2021-09-15 at 22:32 -0500, Benjamin Marzinski wrote: > On Fri, Sep 10, 2021 at 01:41:15PM +0200, mwilck@suse.com=A0wrote: > > From: Martin Wilck > >=20 > > This patch sets up the bulk of the state machine. The idea is to > > fall through the case labels as long as possible (when steps > > succeed) > > and return to the caller if either an error occurs, or it becomes > > necessary to wait for some pollable condition. > >=20 > > While doing this, switch to negative error codes for the functions > > in uxlsnr.c (e.g. parse_cmd()). Positive return codes are reserved > > for the cli_handler functions themselves. This way we can clearly > > distinguish the error source, and avoid confusion and misleading > > error messages. No cli_handler returns negative values. > >=20 > > Note: with this patch applied, clients may hang and time out if > > the handler fails to acquire the vecs lock. This will be fixed in > > the > > follow-up patch "multipathd: uxlsnr: add idle notification". > >=20 > > Signed-off-by: Martin Wilck > > --- > > =A0multipathd/uxlsnr.c | 145 ++++++++++++++++++++++++---------------- > > ---- > > =A01 file changed, 80 insertions(+), 65 deletions(-) > >=20 > >=20 > > +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0set_client_state(c, CLT_W= AIT_LOCK); >=20 > I don't have strong feelings about this, but this state machine > doesn't > want to always fall through. sometimes, like if you get -EPERM, you > want > to swith from CLT_PARSE to CLT_SEND.=A0 If instead of fallthroughs, you > just put the switch statement in a loop, and simply returned when you > wanted to break out to uxsock_listen, you could jump from any state > to > any other state, and wouldn't need to have code to skip the actions > of > some states, to enable the follow throughs. Just a thought. Good point. I'll give it a shot and see how it plays out. The end result will probably be better readable. I'll also work on your other points. Regards Martin -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel