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authorKarsten Graul <kgraul@linux.ibm.com>2020-05-30 17:42:37 +0300
committerDavid S. Miller <davem@davemloft.net>2020-05-31 04:12:25 +0300
commitb8ded9de8db34dd209a3dece94cf54fc414e78f7 (patch)
tree3dbc406c8c0caec84fbc5763491d86ea13a9a20f
parentb86a372201153326bad2c7048aef1bd7accbcbbc (diff)
downloadlinux-b8ded9de8db34dd209a3dece94cf54fc414e78f7.tar.xz
net/smc: pre-fetch send buffer outside of send_lock
Pre-fetch send buffer for the CDC validation message before entering the send_lock. Without that the send call might fail with -EBUSY because there are no free buffers and waiting for buffers is not possible under send_lock. Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> Reviewed-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/smc/smc_cdc.c10
-rw-r--r--net/smc/smc_cdc.h4
-rw-r--r--net/smc/smc_core.c18
3 files changed, 21 insertions, 11 deletions
diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index b2b85e1be72c..a47e8855e045 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -116,19 +116,15 @@ int smc_cdc_msg_send(struct smc_connection *conn,
}
/* send a validation msg indicating the move of a conn to an other QP link */
-int smcr_cdc_msg_send_validation(struct smc_connection *conn)
+int smcr_cdc_msg_send_validation(struct smc_connection *conn,
+ struct smc_cdc_tx_pend *pend,
+ struct smc_wr_buf *wr_buf)
{
struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
struct smc_link *link = conn->lnk;
- struct smc_cdc_tx_pend *pend;
- struct smc_wr_buf *wr_buf;
struct smc_cdc_msg *peer;
int rc;
- rc = smc_cdc_get_free_slot(conn, link, &wr_buf, NULL, &pend);
- if (rc)
- return rc;
-
peer = (struct smc_cdc_msg *)wr_buf;
peer->common.type = local->common.type;
peer->len = local->len;
diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h
index 2ddcc5fb5ceb..0a0a89abd38b 100644
--- a/net/smc/smc_cdc.h
+++ b/net/smc/smc_cdc.h
@@ -296,7 +296,9 @@ int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
struct smc_cdc_tx_pend *pend);
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
int smcd_cdc_msg_send(struct smc_connection *conn);
-int smcr_cdc_msg_send_validation(struct smc_connection *conn);
+int smcr_cdc_msg_send_validation(struct smc_connection *conn,
+ struct smc_cdc_tx_pend *pend,
+ struct smc_wr_buf *wr_buf);
int smc_cdc_init(void) __init;
void smcd_cdc_rx_init(struct smc_connection *conn);
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 65de700e1f17..7964a21e5e6f 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -483,7 +483,8 @@ static int smc_write_space(struct smc_connection *conn)
return space;
}
-static int smc_switch_cursor(struct smc_sock *smc)
+static int smc_switch_cursor(struct smc_sock *smc, struct smc_cdc_tx_pend *pend,
+ struct smc_wr_buf *wr_buf)
{
struct smc_connection *conn = &smc->conn;
union smc_host_cursor cons, fin;
@@ -520,11 +521,14 @@ static int smc_switch_cursor(struct smc_sock *smc)
if (smc->sk.sk_state != SMC_INIT &&
smc->sk.sk_state != SMC_CLOSED) {
- rc = smcr_cdc_msg_send_validation(conn);
+ rc = smcr_cdc_msg_send_validation(conn, pend, wr_buf);
if (!rc) {
schedule_delayed_work(&conn->tx_work, 0);
smc->sk.sk_data_ready(&smc->sk);
}
+ } else {
+ smc_wr_tx_put_slot(conn->lnk,
+ (struct smc_wr_tx_pend_priv *)pend);
}
return rc;
}
@@ -533,7 +537,9 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr,
struct smc_link *from_lnk, bool is_dev_err)
{
struct smc_link *to_lnk = NULL;
+ struct smc_cdc_tx_pend *pend;
struct smc_connection *conn;
+ struct smc_wr_buf *wr_buf;
struct smc_sock *smc;
struct rb_node *node;
int i, rc = 0;
@@ -582,10 +588,16 @@ again:
}
sock_hold(&smc->sk);
read_unlock_bh(&lgr->conns_lock);
+ /* pre-fetch buffer outside of send_lock, might sleep */
+ rc = smc_cdc_get_free_slot(conn, to_lnk, &wr_buf, NULL, &pend);
+ if (rc) {
+ smcr_link_down_cond_sched(to_lnk);
+ return NULL;
+ }
/* avoid race with smcr_tx_sndbuf_nonempty() */
spin_lock_bh(&conn->send_lock);
conn->lnk = to_lnk;
- rc = smc_switch_cursor(smc);
+ rc = smc_switch_cursor(smc, pend, wr_buf);
spin_unlock_bh(&conn->send_lock);
sock_put(&smc->sk);
if (rc) {