nvmet-fcloop: Check remoteport port_state before calling done callback

In nvme_fc_handle_ls_rqst_work, the lsrsp->done callback is only set when
remoteport->port_state is FC_OBJSTATE_ONLINE.  Otherwise, the
nvme_fc_xmt_ls_rsp's LLDD call to lport->ops->xmt_ls_rsp is expected to
fail and the nvme-fc transport layer itself will directly call
nvme_fc_xmt_ls_rsp_free instead of relying on LLDD's done callback to free
the lsrsp resources.

Update the fcloop_t2h_xmt_ls_rsp routine to check remoteport->port_state.
If online, then lsrsp->done callback will free the lsrsp.  Else, return
-ENODEV to signal the nvme-fc transport to handle freeing lsrsp.

Cc: Ewan D. Milne <emilne@redhat.com>
Tested-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Closes: https://lore.kernel.org/linux-nvme/21255200-a271-4fa0-b099-97755c8acd4c@work/
Fixes: 10c165a ("nvmet-fcloop: call done callback even when remote port is gone")
Signed-off-by: Justin Tee <justintee8345@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: Justin Tee

drivers/nvme/target/fcloop.c

@@ -491,6 +491,7 @@ fcloop_t2h_xmt_ls_rsp(struct nvme_fc_local_port *localport,
 	struct fcloop_rport *rport = remoteport->private;
 	struct nvmet_fc_target_port *targetport = rport->targetport;
 	struct fcloop_tport *tport;
+	int ret = 0;
 
 	if (!targetport) {
 		/*
@@ -500,12 +501,18 @@ fcloop_t2h_xmt_ls_rsp(struct nvme_fc_local_port *localport,
 		 * We end up here from delete association exchange:
 		 * nvmet_fc_xmt_disconnect_assoc sends an async request.
 		 *
-		 * Return success because this is what LLDDs do; silently
-		 * drop the response.
+		 * Return success when remoteport is still online because this
+		 * is what LLDDs do and silently drop the response.  Otherwise,
+		 * return with error to signal upper layer to perform the lsrsp
+		 * resource cleanup.
 		 */
-		lsrsp->done(lsrsp);
+		if (remoteport->port_state == FC_OBJSTATE_ONLINE)
+			lsrsp->done(lsrsp);
+		else
+			ret = -ENODEV;
+
 		kmem_cache_free(lsreq_cache, tls_req);
-		return 0;
+		return ret;
 	}
 
 	memcpy(lsreq->rspaddr, lsrsp->rspbuf,