net/smc: Introduce a new conn->lgr validity check helper

It is no longer suitable to identify whether a smc connection
is registered in a link group through checking if conn->lgr
is NULL, because conn->lgr won't be reset even the connection
is unregistered from a link group.

So this patch introduces a new helper smc_conn_lgr_valid() and
replaces all the check of conn->lgr in original implementation
with the new helper to judge if conn->lgr is valid to use.

Signed-off-by: Wen Gu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Wen Gu

net/smc/af_smc.c

@@ -634,9 +634,13 @@ static void smc_conn_abort(struct smc_sock *smc, int local_first)
 {
 	struct smc_connection *conn = &smc->conn;
 	struct smc_link_group *lgr = conn->lgr;
+	bool lgr_valid = false;
+
+	if (smc_conn_lgr_valid(conn))
+		lgr_valid = true;
 
 	smc_conn_free(conn);
-	if (local_first)
+	if (local_first && lgr_valid)
 		smc_lgr_cleanup_early(lgr);
 }
 

net/smc/smc_cdc.c

@@ -197,7 +197,8 @@ int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
 {
 	int rc;
 
-	if (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
+	if (!smc_conn_lgr_valid(conn) ||
+	    (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
 		return -EPIPE;
 
 	if (conn->lgr->is_smcd) {

net/smc/smc_clc.c

@@ -774,7 +774,7 @@ int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info, u8 version)
 	dclc.os_type = version == SMC_V1 ? 0 : SMC_CLC_OS_LINUX;
 	dclc.hdr.typev2 = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ?
 						SMC_FIRST_CONTACT_MASK : 0;
-	if ((!smc->conn.lgr || !smc->conn.lgr->is_smcd) &&
+	if ((!smc_conn_lgr_valid(&smc->conn) || !smc->conn.lgr->is_smcd) &&
 	    smc_ib_is_valid_local_systemid())
 		memcpy(dclc.id_for_peer, local_systemid,
 		       sizeof(local_systemid));

net/smc/smc_core.c

@@ -211,7 +211,7 @@ static void smc_lgr_unregister_conn(struct smc_connection *conn)
 {
 	struct smc_link_group *lgr = conn->lgr;
 
-	if (!lgr)
+	if (!smc_conn_lgr_valid(conn))
 		return;
 	write_lock_bh(&lgr->conns_lock);
 	if (conn->alert_token_local) {
@@ -1139,7 +1139,7 @@ void smc_conn_free(struct smc_connection *conn)
 		return;
 
 	conn->freed = 1;
-	if (!conn->alert_token_local)
+	if (!smc_conn_lgr_valid(conn))
 		/* Connection has already unregistered from
 		 * link group.
 		 */
@@ -2278,14 +2278,16 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
 
 void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
+	if (!smc_conn_lgr_valid(conn) || conn->lgr->is_smcd ||
+	    !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_cpu(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
 
 void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
+	if (!smc_conn_lgr_valid(conn) || conn->lgr->is_smcd ||
+	    !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_device(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
@@ -2294,7 +2296,7 @@ void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
 {
 	int i;
 
-	if (!conn->lgr || conn->lgr->is_smcd)
+	if (!smc_conn_lgr_valid(conn) || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 		if (!smc_link_active(&conn->lgr->lnk[i]))
@@ -2308,7 +2310,7 @@ void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
 {
 	int i;
 
-	if (!conn->lgr || conn->lgr->is_smcd)
+	if (!smc_conn_lgr_valid(conn) || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 		if (!smc_link_active(&conn->lgr->lnk[i]))

net/smc/smc_core.h

@@ -410,6 +410,11 @@ static inline struct smc_connection *smc_lgr_find_conn(
 	return res;
 }
 
+static inline bool smc_conn_lgr_valid(struct smc_connection *conn)
+{
+	return conn->lgr && conn->alert_token_local;
+}
+
 /*
  * Returns true if the specified link is usable.
  *

net/smc/smc_diag.c

@@ -89,7 +89,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 	r->diag_state = sk->sk_state;
 	if (smc->use_fallback)
 		r->diag_mode = SMC_DIAG_MODE_FALLBACK_TCP;
-	else if (smc->conn.lgr && smc->conn.lgr->is_smcd)
+	else if (smc_conn_lgr_valid(&smc->conn) && smc->conn.lgr->is_smcd)
 		r->diag_mode = SMC_DIAG_MODE_SMCD;
 	else
 		r->diag_mode = SMC_DIAG_MODE_SMCR;
@@ -142,7 +142,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 			goto errout;
 	}
 
-	if (smc->conn.lgr && !smc->conn.lgr->is_smcd &&
+	if (smc_conn_lgr_valid(&smc->conn) && !smc->conn.lgr->is_smcd &&
 	    (req->diag_ext & (1 << (SMC_DIAG_LGRINFO - 1))) &&
 	    !list_empty(&smc->conn.lgr->list)) {
 		struct smc_link *link = smc->conn.lnk;
@@ -164,7 +164,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 		if (nla_put(skb, SMC_DIAG_LGRINFO, sizeof(linfo), &linfo) < 0)
 			goto errout;
 	}
-	if (smc->conn.lgr && smc->conn.lgr->is_smcd &&
+	if (smc_conn_lgr_valid(&smc->conn) && smc->conn.lgr->is_smcd &&
 	    (req->diag_ext & (1 << (SMC_DIAG_DMBINFO - 1))) &&
 	    !list_empty(&smc->conn.lgr->list)) {
 		struct smc_connection *conn = &smc->conn;