net/smc: add infrastructure to send delete rkey messages

Add the infrastructure to send LLC messages of type DELETE RKEY to
unregister a shared memory region at the peer.

Signed-off-by: Karsten Graul <[e-mail]>
Signed-off-by: Ursula Braun <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/smc/smc_core.h

···
 	int			llc_testlink_time; /* testlink interval */
 	struct completion	llc_confirm_rkey; /* wait 4 rx of cnf rkey */
 	int			llc_confirm_rkey_rc; /* rc from cnf rkey msg */
+	struct completion	llc_delete_rkey; /* wait 4 rx of del rkey */
+	int			llc_delete_rkey_rc; /* rc from del rkey msg */
+	struct mutex		llc_delete_rkey_mutex; /* serialize usage */
 };
 
 /* For now we just allow one parallel link per link group. The SMC protocol

net/smc/smc_llc.c

···
 	return rc;
 }
 
+/* send LLC delete rkey request */
+static int smc_llc_send_delete_rkey(struct smc_link *link,
+				    struct smc_buf_desc *rmb_desc)
+{
+	struct smc_llc_msg_delete_rkey *rkeyllc;
+	struct smc_wr_tx_pend_priv *pend;
+	struct smc_wr_buf *wr_buf;
+	int rc;
+
+	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
+	if (rc)
+		return rc;
+	rkeyllc = (struct smc_llc_msg_delete_rkey *)wr_buf;
+	memset(rkeyllc, 0, sizeof(*rkeyllc));
+	rkeyllc->hd.common.type = SMC_LLC_DELETE_RKEY;
+	rkeyllc->hd.length = sizeof(struct smc_llc_msg_delete_rkey);
+	rkeyllc->num_rkeys = 1;
+	rkeyllc->rkey[0] = htonl(rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
+	/* send llc message */
+	rc = smc_wr_tx_send(link, pend);
+	return rc;
+}
+
 /* prepare an add link message */
 static void smc_llc_prep_add_link(struct smc_llc_msg_add_link *addllc,
 				  struct smc_link *link, u8 mac[], u8 gid[],
···
 	int i, max;
 
 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		/* unused as long as we don't send this type of msg */
+		link->llc_delete_rkey_rc = llc->hd.flags &
+					    SMC_LLC_FLAG_RKEY_NEG;
+		complete(&link->llc_delete_rkey);
 	} else {
 		max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
 		for (i = 0; i < max; i++) {
···
 	init_completion(&link->llc_add);
 	init_completion(&link->llc_add_resp);
 	init_completion(&link->llc_confirm_rkey);
+	init_completion(&link->llc_delete_rkey);
+	mutex_init(&link->llc_delete_rkey_mutex);
 	init_completion(&link->llc_testlink_resp);
 	INIT_DELAYED_WORK(&link->llc_testlink_wrk, smc_llc_testlink_work);
 	return 0;
···
 {
 	int rc;
 
+	/* protected by mutex smc_create_lgr_pending */
 	reinit_completion(&link->llc_confirm_rkey);
 	rc = smc_llc_send_confirm_rkey(link, rmb_desc);
 	if (rc)
···
 	if (rc <= 0 || link->llc_confirm_rkey_rc)
 		return -EFAULT;
 	return 0;
+}
+
+/* unregister an rtoken at the remote peer */
+int smc_llc_do_delete_rkey(struct smc_link *link,
+			   struct smc_buf_desc *rmb_desc)
+{
+	int rc;
+
+	mutex_lock(&link->llc_delete_rkey_mutex);
+	reinit_completion(&link->llc_delete_rkey);
+	rc = smc_llc_send_delete_rkey(link, rmb_desc);
+	if (rc)
+		goto out;
+	/* receive DELETE RKEY response from server over RoCE fabric */
+	rc = wait_for_completion_interruptible_timeout(&link->llc_delete_rkey,
+						       SMC_LLC_WAIT_TIME);
+	if (rc <= 0 || link->llc_delete_rkey_rc)
+		rc = -EFAULT;
+	else
+		rc = 0;
+out:
+	mutex_unlock(&link->llc_delete_rkey_mutex);
+	return rc;
 }
 
 /***************************** init, exit, misc ******************************/

net/smc/smc_llc.h

···
 void smc_llc_link_clear(struct smc_link *link);
 int smc_llc_do_confirm_rkey(struct smc_link *link,
 			    struct smc_buf_desc *rmb_desc);
+int smc_llc_do_delete_rkey(struct smc_link *link,
+			   struct smc_buf_desc *rmb_desc);
 int smc_llc_init(void) __init;
 
 #endif /* SMC_LLC_H */