From: Karsten Graul <kgraul@linux.ibm.com>
Date: Thu, 3 May 2018 17:57:38 +0200
Subject: net/smc: handle unregistered buffers
Patch-mainline: v4.17-rc4
Git-commit: a6920d1d130c3de039be982eba42542d329dc64c
References: bsc#1096003, FATE#325023, LTC#164003

When smc_wr_reg_send() fails then tag (regerr) the affected buffer and
free it in smc_buf_unuse().

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 net/smc/af_smc.c   |  4 +++-
 net/smc/smc_core.c | 22 +++++++++++++++++++---
 net/smc/smc_core.h |  3 ++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index fdb2976117bd..d03b8d29ffc0 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -296,8 +296,10 @@ static void smc_copy_sock_settings_to_smc(struct smc_sock *smc)
 static int smc_reg_rmb(struct smc_link *link, struct smc_buf_desc *rmb_desc)
 {
 	/* register memory region for new rmb */
-	if (smc_wr_reg_send(link, rmb_desc->mr_rx[SMC_SINGLE_LINK]))
+	if (smc_wr_reg_send(link, rmb_desc->mr_rx[SMC_SINGLE_LINK])) {
+		rmb_desc->regerr = 1;
 		return -EFAULT;
+	}
 	return 0;
 }
 
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index f44f6803f7ff..d4bd01bb44e1 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -32,6 +32,9 @@
 
 static u32 smc_lgr_num;			/* unique link group number */
 
+static void smc_buf_free(struct smc_buf_desc *buf_desc, struct smc_link *lnk,
+			 bool is_rmb);
+
 static void smc_lgr_schedule_free_work(struct smc_link_group *lgr)
 {
 	/* client link group creation always follows the server link group
@@ -234,9 +237,22 @@ static void smc_buf_unuse(struct smc_connection *conn)
 		conn->sndbuf_size = 0;
 	}
 	if (conn->rmb_desc) {
-		conn->rmb_desc->reused = true;
-		conn->rmb_desc->used = 0;
-		conn->rmbe_size = 0;
+		if (!conn->rmb_desc->regerr) {
+			conn->rmb_desc->reused = 1;
+			conn->rmb_desc->used = 0;
+			conn->rmbe_size = 0;
+		} else {
+			/* buf registration failed, reuse not possible */
+			struct smc_link_group *lgr = conn->lgr;
+			struct smc_link *lnk;
+
+			write_lock_bh(&lgr->rmbs_lock);
+			list_del(&conn->rmb_desc->list);
+			write_unlock_bh(&lgr->rmbs_lock);
+
+			lnk = &lgr->lnk[SMC_SINGLE_LINK];
+			smc_buf_free(conn->rmb_desc, lnk, true);
+		}
 	}
 }
 
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 07e2a393e6d9..5dfcb15d529f 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -123,7 +123,8 @@ struct smc_buf_desc {
 						 */
 	u32			order;		/* allocation order */
 	u32			used;		/* currently used / unused */
-	bool			reused;		/* new created / reused */
+	u8			reused	: 1;	/* new created / reused */
+	u8			regerr	: 1;	/* err during registration */
 };
 
 struct smc_rtoken {				/* address/key of remote RMB */