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Message-Id: <20200430135551.26267-2-kgraul@linux.ibm.com>
Date: Thu, 30 Apr 2020 15:55:38 +0200
From: Karsten Graul <kgraul@...ux.ibm.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, linux-s390@...r.kernel.org,
heiko.carstens@...ibm.com, raspl@...ux.ibm.com,
ubraun@...ux.ibm.com
Subject: [PATCH net-next 01/14] net/smc: add event-based llc_flow framework
The new framework allows to start specific types of LLC control flows,
protects active flows and makes it possible to wait for flows to finish
before starting a new flow.
This mechanism is used for the LLC control layer to model flows like
'add link' or 'delete link' which need to send/receive several LLC
messages and are not allowed to get interrupted by the wrong type of
messages.
'Add link' or 'Delete link' messages arriving in the middle of a flow
are delayed and processed when the current flow finished.
Signed-off-by: Karsten Graul <kgraul@...ux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@...ux.ibm.com>
---
net/smc/smc_core.c | 2 +
net/smc/smc_core.h | 24 +++++++
net/smc/smc_llc.c | 165 +++++++++++++++++++++++++++++++++++++++++++++
net/smc/smc_llc.h | 8 +++
4 files changed, 199 insertions(+)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index db49f8cd5c95..4867ddcfe0c6 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -263,6 +263,7 @@ static void smc_lgr_free_work(struct work_struct *work)
if (smc_link_usable(lnk))
lnk->state = SMC_LNK_INACTIVE;
}
+ wake_up_interruptible_all(&lgr->llc_waiter);
}
smc_lgr_free(lgr);
}
@@ -696,6 +697,7 @@ static void smc_lgr_cleanup(struct smc_link_group *lgr)
if (smc_link_usable(lnk))
lnk->state = SMC_LNK_INACTIVE;
}
+ wake_up_interruptible_all(&lgr->llc_waiter);
}
}
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index b5781511063d..70399217ad6f 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -197,6 +197,20 @@ struct smc_rtoken { /* address/key of remote RMB */
struct smcd_dev;
+enum smc_llc_flowtype {
+ SMC_LLC_FLOW_NONE = 0,
+ SMC_LLC_FLOW_ADD_LINK = 2,
+ SMC_LLC_FLOW_DEL_LINK = 4,
+ SMC_LLC_FLOW_RKEY = 6,
+};
+
+struct smc_llc_qentry;
+
+struct smc_llc_flow {
+ enum smc_llc_flowtype type;
+ struct smc_llc_qentry *qentry;
+};
+
struct smc_link_group {
struct list_head list;
struct rb_root conns_all; /* connection tree */
@@ -238,6 +252,16 @@ struct smc_link_group {
/* protects llc_event_q */
struct work_struct llc_event_work;
/* llc event worker */
+ wait_queue_head_t llc_waiter;
+ /* w4 next llc event */
+ struct smc_llc_flow llc_flow_lcl;
+ /* llc local control field */
+ struct smc_llc_flow llc_flow_rmt;
+ /* llc remote control field */
+ struct smc_llc_qentry *delayed_event;
+ /* arrived when flow active */
+ spinlock_t llc_flow_lock;
+ /* protects llc flow */
int llc_testlink_time;
/* link keep alive time */
};
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index e715dd6735ee..647cf1a2dfa5 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -140,6 +140,154 @@ struct smc_llc_qentry {
union smc_llc_msg msg;
};
+struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow)
+{
+ struct smc_llc_qentry *qentry = flow->qentry;
+
+ flow->qentry = NULL;
+ return qentry;
+}
+
+void smc_llc_flow_qentry_del(struct smc_llc_flow *flow)
+{
+ struct smc_llc_qentry *qentry;
+
+ if (flow->qentry) {
+ qentry = flow->qentry;
+ flow->qentry = NULL;
+ kfree(qentry);
+ }
+}
+
+static inline void smc_llc_flow_qentry_set(struct smc_llc_flow *flow,
+ struct smc_llc_qentry *qentry)
+{
+ flow->qentry = qentry;
+}
+
+/* try to start a new llc flow, initiated by an incoming llc msg */
+static bool smc_llc_flow_start(struct smc_llc_flow *flow,
+ struct smc_llc_qentry *qentry)
+{
+ struct smc_link_group *lgr = qentry->link->lgr;
+
+ spin_lock_bh(&lgr->llc_flow_lock);
+ if (flow->type) {
+ /* a flow is already active */
+ if ((qentry->msg.raw.hdr.common.type == SMC_LLC_ADD_LINK ||
+ qentry->msg.raw.hdr.common.type == SMC_LLC_DELETE_LINK) &&
+ !lgr->delayed_event) {
+ lgr->delayed_event = qentry;
+ } else {
+ /* forget this llc request */
+ kfree(qentry);
+ }
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ return false;
+ }
+ switch (qentry->msg.raw.hdr.common.type) {
+ case SMC_LLC_ADD_LINK:
+ flow->type = SMC_LLC_FLOW_ADD_LINK;
+ break;
+ case SMC_LLC_DELETE_LINK:
+ flow->type = SMC_LLC_FLOW_DEL_LINK;
+ break;
+ case SMC_LLC_CONFIRM_RKEY:
+ case SMC_LLC_DELETE_RKEY:
+ flow->type = SMC_LLC_FLOW_RKEY;
+ break;
+ default:
+ flow->type = SMC_LLC_FLOW_NONE;
+ }
+ if (qentry == lgr->delayed_event)
+ lgr->delayed_event = NULL;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ smc_llc_flow_qentry_set(flow, qentry);
+ return true;
+}
+
+/* start a new local llc flow, wait till current flow finished */
+int smc_llc_flow_initiate(struct smc_link_group *lgr,
+ enum smc_llc_flowtype type)
+{
+ enum smc_llc_flowtype allowed_remote = SMC_LLC_FLOW_NONE;
+ int rc;
+
+ /* all flows except confirm_rkey and delete_rkey are exclusive,
+ * confirm/delete rkey flows can run concurrently (local and remote)
+ */
+ if (type == SMC_LLC_FLOW_RKEY)
+ allowed_remote = SMC_LLC_FLOW_RKEY;
+again:
+ if (list_empty(&lgr->list))
+ return -ENODEV;
+ spin_lock_bh(&lgr->llc_flow_lock);
+ if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
+ (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
+ lgr->llc_flow_rmt.type == allowed_remote)) {
+ lgr->llc_flow_lcl.type = type;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ return 0;
+ }
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ rc = wait_event_interruptible_timeout(lgr->llc_waiter,
+ (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
+ (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
+ lgr->llc_flow_rmt.type == allowed_remote)),
+ SMC_LLC_WAIT_TIME);
+ if (!rc)
+ return -ETIMEDOUT;
+ goto again;
+}
+
+/* finish the current llc flow */
+void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow)
+{
+ spin_lock_bh(&lgr->llc_flow_lock);
+ memset(flow, 0, sizeof(*flow));
+ flow->type = SMC_LLC_FLOW_NONE;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ if (!list_empty(&lgr->list) && lgr->delayed_event &&
+ flow == &lgr->llc_flow_lcl)
+ schedule_work(&lgr->llc_event_work);
+ else
+ wake_up_interruptible(&lgr->llc_waiter);
+}
+
+/* lnk is optional and used for early wakeup when link goes down, useful in
+ * cases where we wait for a response on the link after we sent a request
+ */
+struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
+ struct smc_link *lnk,
+ int time_out, u8 exp_msg)
+{
+ struct smc_llc_flow *flow = &lgr->llc_flow_lcl;
+
+ wait_event_interruptible_timeout(lgr->llc_waiter,
+ (flow->qentry ||
+ (lnk && !smc_link_usable(lnk)) ||
+ list_empty(&lgr->list)),
+ time_out);
+ if (!flow->qentry ||
+ (lnk && !smc_link_usable(lnk)) || list_empty(&lgr->list)) {
+ smc_llc_flow_qentry_del(flow);
+ goto out;
+ }
+ if (exp_msg && flow->qentry->msg.raw.hdr.common.type != exp_msg) {
+ if (exp_msg == SMC_LLC_ADD_LINK &&
+ flow->qentry->msg.raw.hdr.common.type ==
+ SMC_LLC_DELETE_LINK) {
+ /* flow_start will delay the unexpected msg */
+ smc_llc_flow_start(&lgr->llc_flow_lcl,
+ smc_llc_flow_qentry_clr(flow));
+ return NULL;
+ }
+ smc_llc_flow_qentry_del(flow);
+ }
+out:
+ return flow->qentry;
+}
+
/********************************** send *************************************/
struct smc_llc_tx_pend {
@@ -547,6 +695,16 @@ static void smc_llc_event_work(struct work_struct *work)
llc_event_work);
struct smc_llc_qentry *qentry;
+ if (!lgr->llc_flow_lcl.type && lgr->delayed_event) {
+ if (smc_link_usable(lgr->delayed_event->link)) {
+ smc_llc_event_handler(lgr->delayed_event);
+ } else {
+ qentry = lgr->delayed_event;
+ lgr->delayed_event = NULL;
+ kfree(qentry);
+ }
+ }
+
again:
spin_lock_bh(&lgr->llc_event_q_lock);
if (!list_empty(&lgr->llc_event_q)) {
@@ -676,6 +834,8 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
INIT_WORK(&lgr->llc_event_work, smc_llc_event_work);
INIT_LIST_HEAD(&lgr->llc_event_q);
spin_lock_init(&lgr->llc_event_q_lock);
+ spin_lock_init(&lgr->llc_flow_lock);
+ init_waitqueue_head(&lgr->llc_waiter);
lgr->llc_testlink_time = net->ipv4.sysctl_tcp_keepalive_time;
}
@@ -683,7 +843,12 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
void smc_llc_lgr_clear(struct smc_link_group *lgr)
{
smc_llc_event_flush(lgr);
+ wake_up_interruptible_all(&lgr->llc_waiter);
cancel_work_sync(&lgr->llc_event_work);
+ if (lgr->delayed_event) {
+ kfree(lgr->delayed_event);
+ lgr->delayed_event = NULL;
+ }
}
int smc_llc_link_init(struct smc_link *link)
diff --git a/net/smc/smc_llc.h b/net/smc/smc_llc.h
index 66063f22166b..49e99ff00ee7 100644
--- a/net/smc/smc_llc.h
+++ b/net/smc/smc_llc.h
@@ -63,6 +63,14 @@ 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_flow_initiate(struct smc_link_group *lgr,
+ enum smc_llc_flowtype type);
+void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow);
+struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
+ struct smc_link *lnk,
+ int time_out, u8 exp_msg);
+struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow);
+void smc_llc_flow_qentry_del(struct smc_llc_flow *flow);
int smc_llc_init(void) __init;
#endif /* SMC_LLC_H */
--
2.17.1
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