net/smc: improved fix wait on already cleared link

Commit 8f3d65c16679 ("net/smc: fix wait on already cleared link")
introduced link refcounting to avoid waits on already cleared links.
This patch extents and improves the refcounting to cover all
remaining possible cases for this kind of error situation.

Fixes: 15e1b99aadfb ("net/smc: no WR buffer wait for terminating link group")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 49 insertions, 14 deletions

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 2e7560eba981..72f4b72eb175 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -383,9 +383,11 @@ int smc_llc_send_confirm_link(struct smc_link *link,
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
 	memset(confllc, 0, sizeof(*confllc));
 	confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
@@ -402,6 +404,8 @@ int smc_llc_send_confirm_link(struct smc_link *link,
 	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
 	return rc;
 }
 
@@ -415,9 +419,11 @@ static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
 	struct smc_link *link;
 	int i, rc, rtok_ix;
 
+	if (!smc_wr_tx_link_hold(send_link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(send_link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	rkeyllc = (struct smc_llc_msg_confirm_rkey *)wr_buf;
 	memset(rkeyllc, 0, sizeof(*rkeyllc));
 	rkeyllc->hd.common.type = SMC_LLC_CONFIRM_RKEY;
@@ -444,6 +450,8 @@ static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
 		(u64)sg_dma_address(rmb_desc->sgt[send_link->link_idx].sgl));
 	/* send llc message */
 	rc = smc_wr_tx_send(send_link, pend);
+put_out:
+	smc_wr_tx_link_put(send_link);
 	return rc;
 }
 
@@ -456,9 +464,11 @@ static int smc_llc_send_delete_rkey(struct smc_link *link,
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	rkeyllc = (struct smc_llc_msg_delete_rkey *)wr_buf;
 	memset(rkeyllc, 0, sizeof(*rkeyllc));
 	rkeyllc->hd.common.type = SMC_LLC_DELETE_RKEY;
@@ -467,6 +477,8 @@ static int smc_llc_send_delete_rkey(struct smc_link *link,
 	rkeyllc->rkey[0] = htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
 	return rc;
 }
 
@@ -480,9 +492,11 @@ int smc_llc_send_add_link(struct smc_link *link, u8 mac[], u8 gid[],
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	addllc = (struct smc_llc_msg_add_link *)wr_buf;
 
 	memset(addllc, 0, sizeof(*addllc));
@@ -504,6 +518,8 @@ int smc_llc_send_add_link(struct smc_link *link, u8 mac[], u8 gid[],
 	}
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
 	return rc;
 }
 
@@ -517,9 +533,11 @@ int smc_llc_send_delete_link(struct smc_link *link, u8 link_del_id,
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	delllc = (struct smc_llc_msg_del_link *)wr_buf;
 
 	memset(delllc, 0, sizeof(*delllc));
@@ -536,6 +554,8 @@ int smc_llc_send_delete_link(struct smc_link *link, u8 link_del_id,
 	delllc->reason = htonl(reason);
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
 	return rc;
 }
 
@@ -547,9 +567,11 @@ static int smc_llc_send_test_link(struct smc_link *link, u8 user_data[16])
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	testllc = (struct smc_llc_msg_test_link *)wr_buf;
 	memset(testllc, 0, sizeof(*testllc));
 	testllc->hd.common.type = SMC_LLC_TEST_LINK;
@@ -557,6 +579,8 @@ static int smc_llc_send_test_link(struct smc_link *link, u8 user_data[16])
 	memcpy(testllc->user_data, user_data, sizeof(testllc->user_data));
 	/* send llc message */
 	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
 	return rc;
 }
 
@@ -567,13 +591,16 @@ static int smc_llc_send_message(struct smc_link *link, void *llcbuf)
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
-	if (!smc_link_usable(link))
+	if (!smc_wr_tx_link_hold(link))
 		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
-	return smc_wr_tx_send(link, pend);
+	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
+	return rc;
 }
 
 /* schedule an llc send on link, may wait for buffers,
@@ -586,13 +613,16 @@ static int smc_llc_send_message_wait(struct smc_link *link, void *llcbuf)
 	struct smc_wr_buf *wr_buf;
 	int rc;
 
-	if (!smc_link_usable(link))
+	if (!smc_wr_tx_link_hold(link))
 		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
-	return smc_wr_tx_send_wait(link, pend, SMC_LLC_WAIT_TIME);
+	rc = smc_wr_tx_send_wait(link, pend, SMC_LLC_WAIT_TIME);
+put_out:
+	smc_wr_tx_link_put(link);
+	return rc;
 }
 
 /********************************* receive ***********************************/
@@ -672,9 +702,11 @@ static int smc_llc_add_link_cont(struct smc_link *link,
 	struct smc_buf_desc *rmb;
 	u8 n;
 
+	if (!smc_wr_tx_link_hold(link))
+		return -ENOLINK;
 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
 	if (rc)
-		return rc;
+		goto put_out;
 	addc_llc = (struct smc_llc_msg_add_link_cont *)wr_buf;
 	memset(addc_llc, 0, sizeof(*addc_llc));
 
@@ -706,7 +738,10 @@ static int smc_llc_add_link_cont(struct smc_link *link,
 	addc_llc->hd.length = sizeof(struct smc_llc_msg_add_link_cont);
 	if (lgr->role == SMC_CLNT)
 		addc_llc->hd.flags |= SMC_LLC_FLAG_RESP;
-	return smc_wr_tx_send(link, pend);
+	rc = smc_wr_tx_send(link, pend);
+put_out:
+	smc_wr_tx_link_put(link);
+	return rc;
 }
 
 static int smc_llc_cli_rkey_exchange(struct smc_link *link,