net/smc: process llc responses in tasklet context

When llc responses are received then possible waiters for this response
are to be notified. This can be done in tasklet context, without to
use a work in the llc work queue. Move all code that handles llc
responses into smc_llc_rx_response().

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>

2 files changed, 116 insertions, 108 deletions

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 6548e9a06f73..d785656b3489 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -129,10 +129,10 @@ struct smc_link {
 	struct delayed_work	llc_testlink_wrk; /* testlink worker */
 	struct completion	llc_testlink_resp; /* wait for rx of testlink */
 	int			llc_testlink_time; /* testlink interval */
-	struct completion	llc_confirm_rkey; /* wait 4 rx of cnf rkey */
-	int			llc_confirm_rkey_rc; /* rc from cnf rkey msg */
-	struct completion	llc_delete_rkey; /* wait 4 rx of del rkey */
-	int			llc_delete_rkey_rc; /* rc from del rkey msg */
+	struct completion	llc_confirm_rkey_resp; /* w4 rx of cnf rkey */
+	int			llc_confirm_rkey_resp_rc; /* rc from cnf rkey */
+	struct completion	llc_delete_rkey_resp; /* w4 rx of del rkey */
+	int			llc_delete_rkey_resp_rc; /* rc from del rkey */
 	struct mutex		llc_delete_rkey_mutex; /* serialize usage */
 };
 
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index be74876a36ae..265889c8b03b 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -384,27 +384,17 @@ static void smc_llc_rx_confirm_link(struct smc_link *link,
 				    struct smc_llc_msg_confirm_link *llc)
 {
 	struct smc_link_group *lgr = smc_get_lgr(link);
-	int conf_rc;
+	int conf_rc = 0;
 
 	/* RMBE eyecatchers are not supported */
-	if (llc->hd.flags & SMC_LLC_FLAG_NO_RMBE_EYEC)
-		conf_rc = 0;
-	else
+	if (!(llc->hd.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
 		conf_rc = ENOTSUPP;
 
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		if (lgr->role == SMC_SERV &&
-		    link->state == SMC_LNK_ACTIVATING) {
-			link->llc_confirm_resp_rc = conf_rc;
-			complete(&link->llc_confirm_resp);
-		}
-	} else {
-		if (lgr->role == SMC_CLNT &&
-		    link->state == SMC_LNK_ACTIVATING) {
-			link->llc_confirm_rc = conf_rc;
-			link->link_id = llc->link_num;
-			complete(&link->llc_confirm);
-		}
+	if (lgr->role == SMC_CLNT &&
+	    link->state == SMC_LNK_ACTIVATING) {
+		link->llc_confirm_rc = conf_rc;
+		link->link_id = llc->link_num;
+		complete(&link->llc_confirm);
 	}
 }
 
@@ -413,27 +403,22 @@ static void smc_llc_rx_add_link(struct smc_link *link,
 {
 	struct smc_link_group *lgr = smc_get_lgr(link);
 
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		if (link->state == SMC_LNK_ACTIVATING)
-			complete(&link->llc_add_resp);
-	} else {
-		if (link->state == SMC_LNK_ACTIVATING) {
-			complete(&link->llc_add);
-			return;
-		}
+	if (link->state == SMC_LNK_ACTIVATING) {
+		complete(&link->llc_add);
+		return;
+	}
 
-		if (lgr->role == SMC_SERV) {
-			smc_llc_prep_add_link(llc, link,
-					link->smcibdev->mac[link->ibport - 1],
-					link->gid, SMC_LLC_REQ);
+	if (lgr->role == SMC_SERV) {
+		smc_llc_prep_add_link(llc, link,
+				link->smcibdev->mac[link->ibport - 1],
+				link->gid, SMC_LLC_REQ);
 
-		} else {
-			smc_llc_prep_add_link(llc, link,
-					link->smcibdev->mac[link->ibport - 1],
-					link->gid, SMC_LLC_RESP);
-		}
-		smc_llc_send_message(link, llc);
+	} else {
+		smc_llc_prep_add_link(llc, link,
+				link->smcibdev->mac[link->ibport - 1],
+				link->gid, SMC_LLC_RESP);
 	}
+	smc_llc_send_message(link, llc);
 }
 
 static void smc_llc_rx_delete_link(struct smc_link *link,
@@ -441,34 +426,24 @@ static void smc_llc_rx_delete_link(struct smc_link *link,
 {
 	struct smc_link_group *lgr = smc_get_lgr(link);
 
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		if (lgr->role == SMC_SERV)
-			smc_lgr_schedule_free_work_fast(lgr);
+	smc_lgr_forget(lgr);
+	smc_llc_link_deleting(link);
+	if (lgr->role == SMC_SERV) {
+		/* client asks to delete this link, send request */
+		smc_llc_prep_delete_link(llc, link, SMC_LLC_REQ, true);
 	} else {
-		smc_lgr_forget(lgr);
-		smc_llc_link_deleting(link);
-		if (lgr->role == SMC_SERV) {
-			/* client asks to delete this link, send request */
-			smc_llc_prep_delete_link(llc, link, SMC_LLC_REQ, true);
-		} else {
-			/* server requests to delete this link, send response */
-			smc_llc_prep_delete_link(llc, link, SMC_LLC_RESP, true);
-		}
-		smc_llc_send_message(link, llc);
-		smc_lgr_terminate_sched(lgr);
+		/* server requests to delete this link, send response */
+		smc_llc_prep_delete_link(llc, link, SMC_LLC_RESP, true);
 	}
+	smc_llc_send_message(link, llc);
+	smc_lgr_terminate_sched(lgr);
 }
 
 static void smc_llc_rx_test_link(struct smc_link *link,
 				 struct smc_llc_msg_test_link *llc)
 {
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		if (link->state == SMC_LNK_ACTIVE)
-			complete(&link->llc_testlink_resp);
-	} else {
-		llc->hd.flags |= SMC_LLC_FLAG_RESP;
-		smc_llc_send_message(link, llc);
-	}
+	llc->hd.flags |= SMC_LLC_FLAG_RESP;
+	smc_llc_send_message(link, llc);
 }
 
 static void smc_llc_rx_confirm_rkey(struct smc_link *link,
@@ -476,34 +451,24 @@ static void smc_llc_rx_confirm_rkey(struct smc_link *link,
 {
 	int rc;
 
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		link->llc_confirm_rkey_rc = llc->hd.flags &
-					    SMC_LLC_FLAG_RKEY_NEG;
-		complete(&link->llc_confirm_rkey);
-	} else {
-		rc = smc_rtoken_add(link,
-				    llc->rtoken[0].rmb_vaddr,
-				    llc->rtoken[0].rmb_key);
+	rc = smc_rtoken_add(link,
+			    llc->rtoken[0].rmb_vaddr,
+			    llc->rtoken[0].rmb_key);
 
-		/* ignore rtokens for other links, we have only one link */
+	/* ignore rtokens for other links, we have only one link */
 
-		llc->hd.flags |= SMC_LLC_FLAG_RESP;
-		if (rc < 0)
-			llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
-		smc_llc_send_message(link, llc);
-	}
+	llc->hd.flags |= SMC_LLC_FLAG_RESP;
+	if (rc < 0)
+		llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
+	smc_llc_send_message(link, llc);
 }
 
 static void smc_llc_rx_confirm_rkey_cont(struct smc_link *link,
 				      struct smc_llc_msg_confirm_rkey_cont *llc)
 {
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		/* unused as long as we don't send this type of msg */
-	} else {
-		/* ignore rtokens for other links, we have only one link */
-		llc->hd.flags |= SMC_LLC_FLAG_RESP;
-		smc_llc_send_message(link, llc);
-	}
+	/* ignore rtokens for other links, we have only one link */
+	llc->hd.flags |= SMC_LLC_FLAG_RESP;
+	smc_llc_send_message(link, llc);
 }
 
 static void smc_llc_rx_delete_rkey(struct smc_link *link,
@@ -512,25 +477,19 @@ static void smc_llc_rx_delete_rkey(struct smc_link *link,
 	u8 err_mask = 0;
 	int i, max;
 
-	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
-		link->llc_delete_rkey_rc = llc->hd.flags &
-					    SMC_LLC_FLAG_RKEY_NEG;
-		complete(&link->llc_delete_rkey);
-	} else {
-		max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
-		for (i = 0; i < max; i++) {
-			if (smc_rtoken_delete(link, llc->rkey[i]))
-				err_mask |= 1 << (SMC_LLC_DEL_RKEY_MAX - 1 - i);
-		}
-
-		if (err_mask) {
-			llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
-			llc->err_mask = err_mask;
-		}
+	max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
+	for (i = 0; i < max; i++) {
+		if (smc_rtoken_delete(link, llc->rkey[i]))
+			err_mask |= 1 << (SMC_LLC_DEL_RKEY_MAX - 1 - i);
+	}
 
-		llc->hd.flags |= SMC_LLC_FLAG_RESP;
-		smc_llc_send_message(link, llc);
+	if (err_mask) {
+		llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
+		llc->err_mask = err_mask;
 	}
+
+	llc->hd.flags |= SMC_LLC_FLAG_RESP;
+	smc_llc_send_message(link, llc);
 }
 
 /* flush the llc event queue */
@@ -601,6 +560,49 @@ again:
 	spin_unlock_bh(&lgr->llc_event_q_lock);
 }
 
+/* process llc responses in tasklet context */
+static void smc_llc_rx_response(struct smc_link *link, union smc_llc_msg *llc)
+{
+	int rc = 0;
+
+	switch (llc->raw.hdr.common.type) {
+	case SMC_LLC_TEST_LINK:
+		if (link->state == SMC_LNK_ACTIVE)
+			complete(&link->llc_testlink_resp);
+		break;
+	case SMC_LLC_CONFIRM_LINK:
+		if (!(llc->raw.hdr.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
+			rc = ENOTSUPP;
+		if (link->lgr->role == SMC_SERV &&
+		    link->state == SMC_LNK_ACTIVATING) {
+			link->llc_confirm_resp_rc = rc;
+			complete(&link->llc_confirm_resp);
+		}
+		break;
+	case SMC_LLC_ADD_LINK:
+		if (link->state == SMC_LNK_ACTIVATING)
+			complete(&link->llc_add_resp);
+		break;
+	case SMC_LLC_DELETE_LINK:
+		if (link->lgr->role == SMC_SERV)
+			smc_lgr_schedule_free_work_fast(link->lgr);
+		break;
+	case SMC_LLC_CONFIRM_RKEY:
+		link->llc_confirm_rkey_resp_rc = llc->raw.hdr.flags &
+						 SMC_LLC_FLAG_RKEY_NEG;
+		complete(&link->llc_confirm_rkey_resp);
+		break;
+	case SMC_LLC_CONFIRM_RKEY_CONT:
+		/* unused as long as we don't send this type of msg */
+		break;
+	case SMC_LLC_DELETE_RKEY:
+		link->llc_delete_rkey_resp_rc = llc->raw.hdr.flags &
+						SMC_LLC_FLAG_RKEY_NEG;
+		complete(&link->llc_delete_rkey_resp);
+		break;
+	}
+}
+
 /* copy received msg and add it to the event queue */
 static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
 {
@@ -615,6 +617,12 @@ static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
 	if (llc->raw.hdr.length != sizeof(*llc))
 		return; /* invalid message */
 
+	/* process responses immediately */
+	if (llc->raw.hdr.flags & SMC_LLC_FLAG_RESP) {
+		smc_llc_rx_response(link, llc);
+		return;
+	}
+
 	qentry = kmalloc(sizeof(*qentry), GFP_ATOMIC);
 	if (!qentry)
 		return;
@@ -667,8 +675,8 @@ int smc_llc_link_init(struct smc_link *link)
 	init_completion(&link->llc_confirm_resp);
 	init_completion(&link->llc_add);
 	init_completion(&link->llc_add_resp);
-	init_completion(&link->llc_confirm_rkey);
-	init_completion(&link->llc_delete_rkey);
+	init_completion(&link->llc_confirm_rkey_resp);
+	init_completion(&link->llc_delete_rkey_resp);
 	mutex_init(&link->llc_delete_rkey_mutex);
 	init_completion(&link->llc_testlink_resp);
 	INIT_WORK(&link->lgr->llc_event_work, smc_llc_event_work);
@@ -708,14 +716,14 @@ int smc_llc_do_confirm_rkey(struct smc_link *link,
 	int rc;
 
 	/* protected by mutex smc_create_lgr_pending */
-	reinit_completion(&link->llc_confirm_rkey);
+	reinit_completion(&link->llc_confirm_rkey_resp);
 	rc = smc_llc_send_confirm_rkey(link, rmb_desc);
 	if (rc)
 		return rc;
 	/* receive CONFIRM RKEY response from server over RoCE fabric */
-	rc = wait_for_completion_interruptible_timeout(&link->llc_confirm_rkey,
-						       SMC_LLC_WAIT_TIME);
-	if (rc <= 0 || link->llc_confirm_rkey_rc)
+	rc = wait_for_completion_interruptible_timeout(
+			&link->llc_confirm_rkey_resp, SMC_LLC_WAIT_TIME);
+	if (rc <= 0 || link->llc_confirm_rkey_resp_rc)
 		return -EFAULT;
 	return 0;
 }
@@ -729,14 +737,14 @@ int smc_llc_do_delete_rkey(struct smc_link *link,
 	mutex_lock(&link->llc_delete_rkey_mutex);
 	if (link->state != SMC_LNK_ACTIVE)
 		goto out;
-	reinit_completion(&link->llc_delete_rkey);
+	reinit_completion(&link->llc_delete_rkey_resp);
 	rc = smc_llc_send_delete_rkey(link, rmb_desc);
 	if (rc)
 		goto out;
 	/* receive DELETE RKEY response from server over RoCE fabric */
-	rc = wait_for_completion_interruptible_timeout(&link->llc_delete_rkey,
-						       SMC_LLC_WAIT_TIME);
-	if (rc <= 0 || link->llc_delete_rkey_rc)
+	rc = wait_for_completion_interruptible_timeout(
+			&link->llc_delete_rkey_resp, SMC_LLC_WAIT_TIME);
+	if (rc <= 0 || link->llc_delete_rkey_resp_rc)
 		rc = -EFAULT;
 	else
 		rc = 0;