Commit 51e3dfa8 authored by Ursula Braun's avatar Ursula Braun Committed by David S. Miller
Browse files

net/smc: fix cleanup for linkgroup setup failures 



If an SMC connection to a certain peer is setup the first time,
a new linkgroup is created. In case of setup failures, such a
linkgroup is unusable and should disappear. As a first step the
linkgroup is removed from the linkgroup list in smc_lgr_forget().

There are 2 problems:
smc_listen_decline() might be called before linkgroup creation
resulting in a crash due to calling smc_lgr_forget() with
parameter NULL.
If a setup failure occurs after linkgroup creation, the connection
is never unregistered from the linkgroup, preventing linkgroup
freeing.

This patch introduces an enhanced smc_lgr_cleanup_early() function
which
* contains a linkgroup check for early smc_listen_decline()
  invocations
* invokes smc_conn_free() to guarantee unregistering of the
  connection.
* schedules fast linkgroup removal of the unusable linkgroup

And the unused function smcd_conn_free() is removed from smc_core.h.

Fixes: 3b2dec26 ("net/smc: restructure client and server code in af_smc")
Fixes: 2a0674ff ("net/smc: improve abnormal termination of link groups")
Signed-off-by: default avatarUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: default avatarKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 402482a6

net/smc/af_smc.c

+15 −10
Original line number Diff line number Diff line
@@ -512,15 +512,18 @@ static int smc_connect_decline_fallback(struct smc_sock *smc, int reason_code) 
static int smc_connect_abort(struct smc_sock *smc, int reason_code,

			     int local_contact)

{

	bool is_smcd = smc->conn.lgr->is_smcd;



	if (local_contact == SMC_FIRST_CONTACT)

		smc_lgr_forget(smc->conn.lgr);

	if (smc->conn.lgr->is_smcd)

		smc_lgr_cleanup_early(&smc->conn);

	else

		smc_conn_free(&smc->conn);

	if (is_smcd)

		/* there is only one lgr role for SMC-D; use server lock */

		mutex_unlock(&smc_server_lgr_pending);

	else

		mutex_unlock(&smc_client_lgr_pending);



	smc_conn_free(&smc->conn);

	smc->connect_nonblock = 0;

	return reason_code;

}
@@ -1091,7 +1094,6 @@ static void smc_listen_out_err(struct smc_sock *new_smc) 
	if (newsmcsk->sk_state == SMC_INIT)

		sock_put(&new_smc->sk); /* passive closing */

	newsmcsk->sk_state = SMC_CLOSED;

	smc_conn_free(&new_smc->conn);



	smc_listen_out(new_smc);

}
@@ -1102,12 +1104,13 @@ static void smc_listen_decline(struct smc_sock *new_smc, int reason_code, 
{

	/* RDMA setup failed, switch back to TCP */

	if (local_contact == SMC_FIRST_CONTACT)

		smc_lgr_forget(new_smc->conn.lgr);

		smc_lgr_cleanup_early(&new_smc->conn);

	else

		smc_conn_free(&new_smc->conn);

	if (reason_code < 0) { /* error, no fallback possible */

		smc_listen_out_err(new_smc);

		return;

	}

	smc_conn_free(&new_smc->conn);

	smc_switch_to_fallback(new_smc);

	new_smc->fallback_rsn = reason_code;

	if (reason_code && reason_code != SMC_CLC_DECL_PEERDECL) {
@@ -1170,7 +1173,8 @@ static int smc_listen_ism_init(struct smc_sock *new_smc, 
			    new_smc->conn.lgr->vlan_id,

			    new_smc->conn.lgr->smcd)) {

		if (ini->cln_first_contact == SMC_FIRST_CONTACT)

			smc_lgr_forget(new_smc->conn.lgr);

			smc_lgr_cleanup_early(&new_smc->conn);

		else

			smc_conn_free(&new_smc->conn);

		return SMC_CLC_DECL_SMCDNOTALK;

	}
@@ -1178,7 +1182,8 @@ static int smc_listen_ism_init(struct smc_sock *new_smc, 
	/* Create send and receive buffers */

	if (smc_buf_create(new_smc, true)) {

		if (ini->cln_first_contact == SMC_FIRST_CONTACT)

			smc_lgr_forget(new_smc->conn.lgr);

			smc_lgr_cleanup_early(&new_smc->conn);

		else

			smc_conn_free(&new_smc->conn);

		return SMC_CLC_DECL_MEM;

	}

net/smc/smc_core.c

+12 −0
Original line number Diff line number Diff line
@@ -162,6 +162,18 @@ static void smc_lgr_unregister_conn(struct smc_connection *conn) 
	conn->lgr = NULL;

}



void smc_lgr_cleanup_early(struct smc_connection *conn)

{

	struct smc_link_group *lgr = conn->lgr;



	if (!lgr)

		return;



	smc_conn_free(conn);

	smc_lgr_forget(lgr);

	smc_lgr_schedule_free_work_fast(lgr);

}



/* Send delete link, either as client to request the initiation

 * of the DELETE LINK sequence from server; or as server to

 * initiate the delete processing. See smc_llc_rx_delete_link().

net/smc/smc_core.h

+1 −1
Original line number Diff line number Diff line
@@ -296,6 +296,7 @@ struct smc_clc_msg_accept_confirm; 
struct smc_clc_msg_local;



void smc_lgr_forget(struct smc_link_group *lgr);

void smc_lgr_cleanup_early(struct smc_connection *conn);

void smc_lgr_terminate(struct smc_link_group *lgr, bool soft);

void smc_port_terminate(struct smc_ib_device *smcibdev, u8 ibport);

void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid,
@@ -316,7 +317,6 @@ int smc_vlan_by_tcpsk(struct socket *clcsock, struct smc_init_info *ini); 


void smc_conn_free(struct smc_connection *conn);

int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini);

void smcd_conn_free(struct smc_connection *conn);

void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr);

int smc_core_init(void);

void smc_core_exit(void);

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