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linux-next/net/smc/smc_cdc.c
Ursula Braun 46c28dbd4c net/smc: no socket state changes in tasklet context
Several state changes occur during SMC socket closing. Currently
state changes triggered locally occur in process context with
lock_sock() taken while state changes triggered by peer occur in
tasklet context with bh_lock_sock() taken. bh_lock_sock() does not
wait till a lock_sock(() task in process context is finished. This
may lead to races in socket state transitions resulting in dangling
SMC-sockets, or it may lead to duplicate SMC socket freeing.
This patch introduces a closing worker to run all state changes under
lock_sock().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11 23:01:14 -04:00

308 lines
8.6 KiB
C

/*
* Shared Memory Communications over RDMA (SMC-R) and RoCE
*
* Connection Data Control (CDC)
* handles flow control
*
* Copyright IBM Corp. 2016
*
* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
*/
#include <linux/spinlock.h>
#include "smc.h"
#include "smc_wr.h"
#include "smc_cdc.h"
#include "smc_tx.h"
#include "smc_rx.h"
#include "smc_close.h"
/********************************** send *************************************/
struct smc_cdc_tx_pend {
struct smc_connection *conn; /* socket connection */
union smc_host_cursor cursor; /* tx sndbuf cursor sent */
union smc_host_cursor p_cursor; /* rx RMBE cursor produced */
u16 ctrl_seq; /* conn. tx sequence # */
};
/* handler for send/transmission completion of a CDC msg */
static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
struct smc_link *link,
enum ib_wc_status wc_status)
{
struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
struct smc_sock *smc;
int diff;
if (!cdcpend->conn)
/* already dismissed */
return;
smc = container_of(cdcpend->conn, struct smc_sock, conn);
bh_lock_sock(&smc->sk);
if (!wc_status) {
diff = smc_curs_diff(cdcpend->conn->sndbuf_size,
&cdcpend->conn->tx_curs_fin,
&cdcpend->cursor);
/* sndbuf_space is decreased in smc_sendmsg */
smp_mb__before_atomic();
atomic_add(diff, &cdcpend->conn->sndbuf_space);
/* guarantee 0 <= sndbuf_space <= sndbuf_size */
smp_mb__after_atomic();
smc_curs_write(&cdcpend->conn->tx_curs_fin,
smc_curs_read(&cdcpend->cursor, cdcpend->conn),
cdcpend->conn);
}
smc_tx_sndbuf_nonfull(smc);
if (smc->sk.sk_state != SMC_ACTIVE)
/* wake up smc_close_wait_tx_pends() */
smc->sk.sk_state_change(&smc->sk);
bh_unlock_sock(&smc->sk);
}
int smc_cdc_get_free_slot(struct smc_link *link,
struct smc_wr_buf **wr_buf,
struct smc_cdc_tx_pend **pend)
{
return smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
(struct smc_wr_tx_pend_priv **)pend);
}
static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
struct smc_cdc_tx_pend *pend)
{
BUILD_BUG_ON_MSG(
sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
BUILD_BUG_ON_MSG(
offsetof(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
"must adapt SMC_WR_TX_SIZE to sizeof(struct smc_cdc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
BUILD_BUG_ON_MSG(
sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
pend->conn = conn;
pend->cursor = conn->tx_curs_sent;
pend->p_cursor = conn->local_tx_ctrl.prod;
pend->ctrl_seq = conn->tx_cdc_seq;
}
int smc_cdc_msg_send(struct smc_connection *conn,
struct smc_wr_buf *wr_buf,
struct smc_cdc_tx_pend *pend)
{
struct smc_link *link;
int rc;
link = &conn->lgr->lnk[SMC_SINGLE_LINK];
smc_cdc_add_pending_send(conn, pend);
conn->tx_cdc_seq++;
conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
&conn->local_tx_ctrl, conn);
rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
if (!rc)
smc_curs_write(&conn->rx_curs_confirmed,
smc_curs_read(&conn->local_tx_ctrl.cons, conn),
conn);
return rc;
}
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
{
struct smc_cdc_tx_pend *pend;
struct smc_wr_buf *wr_buf;
int rc;
rc = smc_cdc_get_free_slot(&conn->lgr->lnk[SMC_SINGLE_LINK], &wr_buf,
&pend);
if (rc)
return rc;
return smc_cdc_msg_send(conn, wr_buf, pend);
}
static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
unsigned long data)
{
struct smc_connection *conn = (struct smc_connection *)data;
struct smc_cdc_tx_pend *cdc_pend =
(struct smc_cdc_tx_pend *)tx_pend;
return cdc_pend->conn == conn;
}
static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
{
struct smc_cdc_tx_pend *cdc_pend =
(struct smc_cdc_tx_pend *)tx_pend;
cdc_pend->conn = NULL;
}
void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
{
struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
smc_cdc_tx_filter, smc_cdc_tx_dismisser,
(unsigned long)conn);
}
bool smc_cdc_tx_has_pending(struct smc_connection *conn)
{
struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
return smc_wr_tx_has_pending(link, SMC_CDC_MSG_TYPE,
smc_cdc_tx_filter, (unsigned long)conn);
}
/********************************* receive ***********************************/
static inline bool smc_cdc_before(u16 seq1, u16 seq2)
{
return (s16)(seq1 - seq2) < 0;
}
static void smc_cdc_msg_recv_action(struct smc_sock *smc,
struct smc_link *link,
struct smc_cdc_msg *cdc)
{
union smc_host_cursor cons_old, prod_old;
struct smc_connection *conn = &smc->conn;
int diff_cons, diff_prod;
if (!cdc->prod_flags.failover_validation) {
if (smc_cdc_before(ntohs(cdc->seqno),
conn->local_rx_ctrl.seqno))
/* received seqno is old */
return;
}
smc_curs_write(&prod_old,
smc_curs_read(&conn->local_rx_ctrl.prod, conn),
conn);
smc_curs_write(&cons_old,
smc_curs_read(&conn->local_rx_ctrl.cons, conn),
conn);
smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
&conn->local_rx_ctrl.cons);
if (diff_cons) {
/* peer_rmbe_space is decreased during data transfer with RDMA
* write
*/
smp_mb__before_atomic();
atomic_add(diff_cons, &conn->peer_rmbe_space);
/* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
smp_mb__after_atomic();
}
diff_prod = smc_curs_diff(conn->rmbe_size, &prod_old,
&conn->local_rx_ctrl.prod);
if (diff_prod) {
/* bytes_to_rcv is decreased in smc_recvmsg */
smp_mb__before_atomic();
atomic_add(diff_prod, &conn->bytes_to_rcv);
/* guarantee 0 <= bytes_to_rcv <= rmbe_size */
smp_mb__after_atomic();
smc->sk.sk_data_ready(&smc->sk);
}
if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
smc->sk.sk_err = ECONNRESET;
conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
}
if (smc_cdc_rxed_any_close_or_senddone(conn)) {
smc->sk.sk_shutdown |= RCV_SHUTDOWN;
if (smc->clcsock && smc->clcsock->sk)
smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
sock_set_flag(&smc->sk, SOCK_DONE);
schedule_work(&conn->close_work);
}
/* piggy backed tx info */
/* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
if (diff_cons && smc_tx_prepared_sends(conn)) {
smc_tx_sndbuf_nonempty(conn);
/* trigger socket release if connection closed */
smc_close_wake_tx_prepared(smc);
}
/* socket connected but not accepted */
if (!smc->sk.sk_socket)
return;
/* data available */
if ((conn->local_rx_ctrl.prod_flags.write_blocked) ||
(conn->local_rx_ctrl.prod_flags.cons_curs_upd_req))
smc_tx_consumer_update(conn);
}
/* called under tasklet context */
static inline void smc_cdc_msg_recv(struct smc_cdc_msg *cdc,
struct smc_link *link, u64 wr_id)
{
struct smc_link_group *lgr = container_of(link, struct smc_link_group,
lnk[SMC_SINGLE_LINK]);
struct smc_connection *connection;
struct smc_sock *smc;
/* lookup connection */
read_lock_bh(&lgr->conns_lock);
connection = smc_lgr_find_conn(ntohl(cdc->token), lgr);
if (!connection) {
read_unlock_bh(&lgr->conns_lock);
return;
}
smc = container_of(connection, struct smc_sock, conn);
sock_hold(&smc->sk);
read_unlock_bh(&lgr->conns_lock);
bh_lock_sock(&smc->sk);
smc_cdc_msg_recv_action(smc, link, cdc);
bh_unlock_sock(&smc->sk);
sock_put(&smc->sk); /* no free sk in softirq-context */
}
/***************************** init, exit, misc ******************************/
static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
{
struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
struct smc_cdc_msg *cdc = buf;
if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
return; /* short message */
if (cdc->len != sizeof(*cdc))
return; /* invalid message */
smc_cdc_msg_recv(cdc, link, wc->wr_id);
}
static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
{
.handler = smc_cdc_rx_handler,
.type = SMC_CDC_MSG_TYPE
},
{
.handler = NULL,
}
};
int __init smc_cdc_init(void)
{
struct smc_wr_rx_handler *handler;
int rc = 0;
for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
INIT_HLIST_NODE(&handler->list);
rc = smc_wr_rx_register_handler(handler);
if (rc)
break;
}
return rc;
}