net/smc: immediate termination for SMCD link groups

SMCD link group termination is called when peer signals its shutdown
of its corresponding link group. For regular shutdowns no connections
exist anymore. For abnormal shutdowns connections must be killed and
their DMBs must be unregistered immediately. That means the SMCR method
to delay the link group freeing several seconds does not fit.

This patch adds immediate termination of a link group and its SMCD
connections and makes sure all SMCD link group related cleanup steps
are finished.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_ism.c

@@ -146,6 +146,10 @@ out:
 int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
 {
 	struct smcd_dmb dmb;
+	int rc = 0;
+
+	if (!dmb_desc->dma_addr)
+		return rc;
 
 	memset(&dmb, 0, sizeof(dmb));
 	dmb.dmb_tok = dmb_desc->token;
@@ -153,7 +157,13 @@ int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
 	dmb.cpu_addr = dmb_desc->cpu_addr;
 	dmb.dma_addr = dmb_desc->dma_addr;
 	dmb.dmb_len = dmb_desc->len;
-	return smcd->ops->unregister_dmb(smcd, &dmb);
+	rc = smcd->ops->unregister_dmb(smcd, &dmb);
+	if (!rc || rc == ISM_ERROR) {
+		dmb_desc->cpu_addr = NULL;
+		dmb_desc->dma_addr = 0;
+	}
+
+	return rc;
 }
 
 int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
@@ -375,7 +385,7 @@ void smcd_handle_irq(struct smcd_dev *smcd, unsigned int dmbno)
 
 	spin_lock_irqsave(&smcd->lock, flags);
 	conn = smcd->conn[dmbno];
-	if (conn)
+	if (conn && !conn->killed)
 		tasklet_schedule(&conn->rx_tsklet);
 	spin_unlock_irqrestore(&smcd->lock, flags);
 }