From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH 04/12] IB/srp: Fix connection state tracking Date: Thu, 30 Apr 2015 18:00:45 +0300 Message-ID: <5542439D.1000107@dev.mellanox.co.il> References: <5541EE21.3050809@sandisk.com> <5541EE9F.8090605@sandisk.com> <5541FB3F.70902@dev.mellanox.co.il> <5542111E.1080305@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5542111E.1080305-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche , Doug Ledford Cc: James Bottomley , Sagi Grimberg , Sebastian Parschauer , linux-rdma , "linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 4/30/2015 2:25 PM, Bart Van Assche wrote: > On 04/30/15 11:51, Sagi Grimberg wrote: >> On 4/30/2015 11:58 AM, Bart Van Assche wrote: >>> - srp_change_conn_state(target, false); >>> + ch->connected = false; >> >> Shouldn't this be protected by the channel lock (like the target)? > > On all CPU architectures I'm familiar with changes of boolean variables > are atomic so I think modifying that variable without locking is fine. > >>> @@ -170,6 +170,7 @@ struct srp_rdma_ch { >>> >>> struct completion tsk_mgmt_done; >>> u8 tsk_mgmt_status; >>> + bool connected; >> >> I generally agree with this flag, but I'm a bit confused about the >> semantics of two connected flags? Also, we check the target connected >> flag on TMFs, although we are executing it on a channel (should we >> check both?) >> >> I'd say keep only the channel connected flag, the target logic needs to >> be mandated by the state. > > I think we need both flags. The ch->connected flag is used only in > srp_destroy_qp() to verify whether a channel has been disconnected > before it is destroyed. The target->connected flag provides an easy way > to test the connected state in e.g. srp_disconnect_target(). We can just as easily check rport state. rport state is modified before target-connected. I still think one is redundant. > And if it > is attempted to send a task management function over a channel that has > just been disconnected that should be fine since any channel disconnect > causes tl_err_work to be queued. That last action will sooner or later > result in a reconnect. Will it be fine to queue commands when the channel is in reconnecting stage? -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html