Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index 4fcb9e6..6ef93c7 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * iSCSI over TCP/IP Data-Path lib
  *
@@ -7,18 +8,6 @@
  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
  * maintained by open-iscsi@googlegroups.com
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published
- * by the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * See the file COPYING included with this distribution for more details.
- *
  * Credits:
  *	Christoph Hellwig
  *	FUJITA Tomonori
@@ -43,6 +32,7 @@
 #include <scsi/scsi_host.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_transport_iscsi.h>
+#include <trace/events/iscsi.h>
 
 #include "iscsi_tcp.h"
 
@@ -65,6 +55,9 @@
 			iscsi_conn_printk(KERN_INFO, _conn,	\
 					     "%s " dbg_fmt,	\
 					     __func__, ##arg);	\
+		iscsi_dbg_trace(trace_iscsi_dbg_tcp,		\
+				&(_conn)->cls_conn->dev,	\
+				"%s " dbg_fmt, __func__, ##arg);\
 	} while (0);
 
 static int iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
@@ -125,12 +118,17 @@
 	BUG_ON(sg->length == 0);
 
 	/*
+	 * We always map for the recv path.
+	 *
 	 * If the page count is greater than one it is ok to send
 	 * to the network layer's zero copy send path. If not we
-	 * have to go the slow sendmsg path. We always map for the
-	 * recv path.
+	 * have to go the slow sendmsg path.
+	 *
+	 * Same goes for slab pages: skb_can_coalesce() allows
+	 * coalescing neighboring slab objects into a single frag which
+	 * triggers one of hardened usercopy checks.
 	 */
-	if (page_count(sg_page(sg)) >= 1 && !recv)
+	if (!recv && page_count(sg_page(sg)) >= 1 && !PageSlab(sg_page(sg)))
 		return;
 
 	if (recv) {
@@ -491,7 +489,7 @@
 	struct iscsi_tcp_task *tcp_task = task->dd_data;
 	struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 	int datasn = be32_to_cpu(rhdr->datasn);
-	unsigned total_in_length = scsi_in(task->sc)->length;
+	unsigned total_in_length = task->sc->sdb.length;
 
 	/*
 	 * lib iscsi will update this in the completion handling if there
@@ -576,11 +574,11 @@
 			      data_length, session->max_burst);
 
 	data_offset = be32_to_cpu(rhdr->data_offset);
-	if (data_offset + data_length > scsi_out(task->sc)->length) {
+	if (data_offset + data_length > task->sc->sdb.length) {
 		iscsi_conn_printk(KERN_ERR, conn,
 				  "invalid R2T with data len %u at offset %u "
 				  "and total length %d\n", data_length,
-				  data_offset, scsi_out(task->sc)->length);
+				  data_offset, task->sc->sdb.length);
 		return ISCSI_ERR_DATALEN;
 	}
 
@@ -692,7 +690,7 @@
 		if (tcp_conn->in.datalen) {
 			struct iscsi_tcp_task *tcp_task = task->dd_data;
 			struct ahash_request *rx_hash = NULL;
-			struct scsi_data_buffer *sdb = scsi_in(task->sc);
+			struct scsi_data_buffer *sdb = &task->sc->sdb;
 
 			/*
 			 * Setup copy of Data-In into the struct scsi_cmnd