From: Ursula Braun <ubraun@linux.ibm.com>
Date: Thu, 3 Sep 2020 21:53:16 +0200
Subject: net/smc: set rx_off for SMCR explicitly
Git-commit: 2d2bfeb8c5c8c95a93c473ca2c7d07cad6943a34
Patch-mainline: v5.9 or v5.9-rc3 (next release)
References: git-fixes

SMC tries to make use of SMCD first. If a problem shows up,
it tries to switch to SMCR. If the SMCD initializing problem shows
up after the SMCD connection has already been initialized, field
rx_off keeps the wrong SMCD value for SMCR, which results in corrupted
data at the receiver.
This patch adds an explicit (re-)setting of field rx_off to zero if the
connection uses SMCR.

Fixes: be244f28d22f ("net/smc: add SMC-D support in data transfer")
Reviewed-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 net/smc/smc_core.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -674,6 +674,8 @@ create:
 	if (ini->is_smcd) {
 		conn->rx_off = sizeof(struct smcd_cdc_msg);
 		smcd_cdc_rx_init(conn); /* init tasklet for this conn */
+	} else {
+		conn->rx_off = 0;
 	}
 #ifndef KERNEL_HAS_ATOMIC64
 	spin_lock_init(&conn->acurs_lock);