Merged revisions 7253-7266,7268-7271 via svnmerge from

svn+ssh://svn.code.sf.net/p/scst/svn/trunk ........ r7253 | vlnb | 2017-10-11 20:22:02 -0700 (Wed, 11 Oct 2017) | 3 lines scst: add example of active non-optimized setup ........ r7254 | bvassche | 2017-10-12 07:56:44 -0700 (Thu, 12 Oct 2017) | 1 line qla2x00t: Fix scst_debug.h include path for the in-tree build ........ r7255 | bvassche | 2017-10-12 08:03:13 -0700 (Thu, 12 Oct 2017) | 1 line scripts/specialize-patch: Fix #elif handling ........ r7256 | vlnb | 2017-10-13 19:18:56 -0700 (Fri, 13 Oct 2017) | 3 lines Unpdate for kernels 4.12+ ........ r7257 | bvassche | 2017-11-11 21:01:16 -0800 (Sat, 11 Nov 2017) | 1 line iscsi-scst/usr/Makefile: Pass -Wno-format-truncation if supported ........ r7258 | bvassche | 2017-11-12 21:48:16 -0800 (Sun, 12 Nov 2017) | 4 lines ib_srpt: Kernel 4.14 build fix Signed-off-by: Peter Vyazovik <fuzzhead0@gmail.com> ........ r7259 | bvassche | 2017-11-12 21:49:08 -0800 (Sun, 12 Nov 2017) | 1 line scst: Introduce the kernel v4.14 bio_set_dev() macro ........ r7260 | bvassche | 2017-11-12 21:50:44 -0800 (Sun, 12 Nov 2017) | 5 lines scst, iscsi-scst: Introduce scst_read(), scst_write(), scst_readv() and scst_writev() This makes it easier to add support for new kernel versions, e.g. kernel version v4.14. ........ r7261 | bvassche | 2017-11-13 08:00:09 -0800 (Mon, 13 Nov 2017) | 1 line scst/src/scst_lib.c: Fix recently introduced checkpatch complaints ........ r7262 | bvassche | 2017-11-13 08:18:00 -0800 (Mon, 13 Nov 2017) | 4 lines scst: Fix build for kernels 3.15 and older blk_rq_set_block_pc() was introduced in kernel 3.16. ........ r7263 | bvassche | 2017-11-13 08:24:16 -0800 (Mon, 13 Nov 2017) | 1 line nightly build: Update kernel versions ........ r7264 | bvassche | 2017-11-13 08:47:10 -0800 (Mon, 13 Nov 2017) | 1 line scst: Address two checkpatch warnings ........ r7265 | bvassche | 2017-11-13 08:47:43 -0800 (Mon, 13 Nov 2017) | 1 line scst/src/scst_targ: Use READ_ONCE() instead of ACCESS_ONCE() ........ r7266 | bvassche | 2017-11-13 08:49:39 -0800 (Mon, 13 Nov 2017) | 1 line fcst/fcst.h: Add identifier names ........ r7268 | bvassche | 2017-11-14 08:37:24 -0800 (Tue, 14 Nov 2017) | 1 line scst: Fix kernel <= 2.6.30 build ........ r7269 | bvassche | 2017-11-14 18:45:57 -0800 (Tue, 14 Nov 2017) | 1 line nightly/bin/nightly: Clone the source code tree quietly ........ r7270 | bvassche | 2017-11-14 18:47:06 -0800 (Tue, 14 Nov 2017) | 1 line nightly build: Update kernel versions ........ r7271 | bvassche | 2017-11-14 18:48:03 -0800 (Tue, 14 Nov 2017) | 1 line nightly/conf/nightly.sendmail: Use mail if mutt is not available ........ git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/3.3.x@7288 d57e44dd-8a1f-0410-8b47-8ef2f437770f
2026-07-24 17:12:51 +00:00 · 2017-12-23 04:30:51 +00:00
parent 491ca9cd95
commit 129cac067c
21 changed files with 521 additions and 153 deletions
@@ -146,36 +146,34 @@ extern struct fc4_prov ft_prov;
 /*
 * SCST interface.
 */
-int ft_send_response(struct scst_cmd *);
-int ft_send_xfer_rdy(struct scst_cmd *);
-void ft_cmd_timeout(struct scst_cmd *);
-void ft_cmd_free(struct scst_cmd *);
-void ft_cmd_tm_done(struct scst_mgmt_cmd *);
-int ft_tgt_release(struct scst_tgt *);
-int ft_tgt_enable(struct scst_tgt *, bool);
-bool ft_tgt_enabled(struct scst_tgt *);
-int ft_report_aen(struct scst_aen *);
-int ft_get_transport_id(struct scst_tgt *, struct scst_session *, uint8_t **);
+int ft_send_response(struct scst_cmd *cmd);
+int ft_send_xfer_rdy(struct scst_cmd *cmd);
+void ft_cmd_timeout(struct scst_cmd *cmd);
+void ft_cmd_free(struct scst_cmd *cmd);
+void ft_cmd_tm_done(struct scst_mgmt_cmd *mcmd);
+int ft_tgt_release(struct scst_tgt *tgt);
+int ft_tgt_enable(struct scst_tgt *tgt, bool enable);
+bool ft_tgt_enabled(struct scst_tgt *tgt);
+int ft_report_aen(struct scst_aen *aen);
+int ft_get_transport_id(struct scst_tgt *tgt, struct scst_session *scst_sess,
+			uint8_t **result);

 /*
 * Session interface.
 */
-int ft_lport_notify(struct notifier_block *, unsigned long, void *);
-void ft_lport_add(struct fc_lport *, void *);
-void ft_lport_del(struct fc_lport *, void *);
+int ft_lport_notify(struct notifier_block *nb, unsigned long event, void *arg);
+void ft_lport_add(struct fc_lport *lport, void *arg);
+void ft_lport_del(struct fc_lport *lport, void *arg);

 /*
 * other internal functions.
 */
-int ft_thread(void *);
 bool ft_test_and_set_cmd_state(struct ft_cmd *fcmd, enum ft_cmd_state old,
 			       enum ft_cmd_state new);
-void ft_recv_req(struct ft_sess *, struct fc_frame *);
-void ft_recv_write_data(struct scst_cmd *, struct fc_frame *);
-int ft_send_read_data(struct scst_cmd *);
-struct ft_tpg *ft_lport_find_tpg(struct fc_lport *);
-struct ft_node_acl *ft_acl_get(struct ft_tpg *, struct fc_rport_priv *);
-void ft_cmd_dump(struct scst_cmd *, const char *);
+void ft_recv_req(struct ft_sess *sess, struct fc_frame *fp);
+void ft_recv_write_data(struct scst_cmd *cmd, struct fc_frame *fp);
+int ft_send_read_data(struct scst_cmd *cmd);
+void ft_cmd_dump(struct scst_cmd *cmd, const char *caller);

 /* #define FCST_INJECT_SEND_ERRORS 2 */

@@ -540,15 +540,15 @@ extern struct kmem_cache *iscsi_conn_cache;
 extern struct kmem_cache *iscsi_sess_cache;

 /* iscsi.c */
-extern struct iscsi_cmnd *cmnd_alloc(struct iscsi_conn *,
+extern struct iscsi_cmnd *cmnd_alloc(struct iscsi_conn *conn,
 	struct iscsi_cmnd *parent);
-extern int cmnd_rx_start(struct iscsi_cmnd *);
+extern int cmnd_rx_start(struct iscsi_cmnd *cmnd);
 extern int cmnd_rx_continue(struct iscsi_cmnd *req);
-extern void cmnd_rx_end(struct iscsi_cmnd *);
-extern void cmnd_tx_start(struct iscsi_cmnd *);
-extern void cmnd_tx_end(struct iscsi_cmnd *);
+extern void cmnd_rx_end(struct iscsi_cmnd *cmnd);
+extern void cmnd_tx_start(struct iscsi_cmnd *cmnd);
+extern void cmnd_tx_end(struct iscsi_cmnd *cmnd);
 extern void req_cmnd_release_force(struct iscsi_cmnd *req);
-extern void rsp_cmnd_release(struct iscsi_cmnd *);
+extern void rsp_cmnd_release(struct iscsi_cmnd *cmnd);
 extern void iscsi_drop_delayed_tm_rsp(struct iscsi_cmnd *tm_rsp);
 extern void cmnd_done(struct iscsi_cmnd *cmnd);
 extern void conn_abort(struct iscsi_conn *conn);
@@ -567,19 +567,21 @@ extern void iscsi_threads_pool_put(struct iscsi_thread_pool *p);
 #ifndef CONFIG_SCST_PROC
 extern struct kobj_type iscsi_conn_ktype;
 #endif
-extern struct iscsi_conn *conn_lookup(struct iscsi_session *, u16);
-extern void conn_reinst_finished(struct iscsi_conn *);
-extern int __add_conn(struct iscsi_session *, struct iscsi_kern_conn_info *);
-extern int __del_conn(struct iscsi_session *, struct iscsi_kern_conn_info *);
-extern void conn_free(struct iscsi_conn *);
+extern struct iscsi_conn *conn_lookup(struct iscsi_session *session, u16 cid);
+extern void conn_reinst_finished(struct iscsi_conn *conn);
+extern int __add_conn(struct iscsi_session *session,
+		      struct iscsi_kern_conn_info *info);
+extern int __del_conn(struct iscsi_session *session,
+		      struct iscsi_kern_conn_info *info);
+extern void conn_free(struct iscsi_conn *conn);
 extern void iscsi_make_conn_rd_active(struct iscsi_conn *conn);
 #define ISCSI_CONN_ACTIVE_CLOSE		1
 #define ISCSI_CONN_DELETING		2
-extern void __mark_conn_closed(struct iscsi_conn *, int);
-extern void mark_conn_closed(struct iscsi_conn *);
-extern void iscsi_make_conn_wr_active(struct iscsi_conn *);
+extern void __mark_conn_closed(struct iscsi_conn *conn, int flags);
+extern void mark_conn_closed(struct iscsi_conn *conn);
+extern void iscsi_make_conn_wr_active(struct iscsi_conn *conn);
 #ifdef CONFIG_SCST_PROC
-extern void conn_info_show(struct seq_file *, struct iscsi_session *);
+extern void conn_info_show(struct seq_file *seq, struct iscsi_session *session);
 #endif
 extern void iscsi_check_tm_data_wait_timeouts(struct iscsi_conn *conn,
 	bool force);
@@ -607,8 +609,8 @@ extern ssize_t iscsi_sysfs_send_event(uint32_t tid,
 	enum iscsi_kern_event_code code,
 	const char *param1, const char *param2, void **data);
 #endif
-extern struct iscsi_target *target_lookup_by_id(u32);
-extern int __add_target(struct iscsi_kern_target_info *);
+extern struct iscsi_target *target_lookup_by_id(u32 id);
+extern int __add_target(struct iscsi_kern_target_info *info);
 extern int __del_target(u32 id);
 extern ssize_t iscsi_sysfs_add_target(const char *target_name, char *params);
 extern ssize_t iscsi_sysfs_del_target(const char *target_name);
@@ -637,23 +639,25 @@ extern const struct attribute *iscsi_sess_attrs[];
 extern const struct attribute *iscsi_acg_attrs[];
 #endif
 extern const struct file_operations session_seq_fops;
-extern struct iscsi_session *session_lookup(struct iscsi_target *, u64);
-extern void sess_reinst_finished(struct iscsi_session *);
-extern int __add_session(struct iscsi_target *,
-	struct iscsi_kern_session_info *);
-extern int __del_session(struct iscsi_target *, u64);
+extern struct iscsi_session *session_lookup(struct iscsi_target *target,
+					    u64 sid);
+extern void sess_reinst_finished(struct iscsi_session *session);
+extern int __add_session(struct iscsi_target *target,
+			 struct iscsi_kern_session_info *info);
+extern int __del_session(struct iscsi_target *target, u64 sid);
 extern int session_free(struct iscsi_session *session, bool del);
 extern void iscsi_sess_force_close(struct iscsi_session *sess);

 /* params.c */
 extern const char *iscsi_get_digest_name(int val, char *res);
 extern const char *iscsi_get_bool_value(int val);
-extern int iscsi_params_set(struct iscsi_target *,
-	struct iscsi_kern_params_info *, int);
+extern int iscsi_params_set(struct iscsi_target *target,
+			    struct iscsi_kern_params_info *info, int set);

 /* event.c */
-extern int event_send(u32, u64, u32, u32, enum iscsi_kern_event_code,
-	const char *param1, const char *param2);
+extern int event_send(u32 tid, u64 sid, u32 cid, u32 cookie,
+		      enum iscsi_kern_event_code code,
+		      const char *param1, const char *param2);
 extern int event_init(void);
 extern void event_exit(void);

@@ -1372,9 +1372,7 @@ static int write_data(struct iscsi_conn *conn)
 retry:
 			oldfs = get_fs();
 			set_fs(KERNEL_DS);
-			res = vfs_writev(file,
-					 (struct iovec __force __user *)iop,
-					 count, &off, 0);
+			res = scst_writev(file, iop, count, &off);
 			set_fs(oldfs);
 			TRACE_WRITE("sid %#Lx, cid %u, res %d, iov_len %zd",
 				    (unsigned long long int)conn->session->sid,
@@ -18,6 +18,9 @@ ifndef PREFIX
        PREFIX=/usr/local
 endif

+cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
+             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+
 SRCS_D = iscsid.c iscsi_scstd.c conn.c session.c target.c message.c ctldev.c \
 		log.c chap.c event.c param.c config.c isns.c md5.c sha1.c \
 		misc.c
@@ -28,7 +31,9 @@ OBJS_ADM = $(SRCS_ADM:.c=.o)

 CFLAGS += -O2 -Wall -Wextra -Wstrict-prototypes -Wno-sign-compare \
 	-Wimplicit-function-declaration -Wno-unused-parameter \
-	-Wno-missing-field-initializers -g -I../include -I$(SCST_INC_DIR)
+	-Wno-missing-field-initializers \
+	$(call cc-option,-Wno-format-truncation) \
+	-g -I../include -I$(SCST_INC_DIR)
 CFLAGS += -D_GNU_SOURCE # required for glibc >= 2.8
 CFLAGS += $(LOCAL_CFLAGS)

@@ -155,7 +155,7 @@ for logfile in old new ; do
             svn co -q -r {${date}} ${scst_repo} ${ABT_TMPDIR}/scst;	\
           else								\
             ( rmdir ${ABT_TMPDIR}/scst &&				\
-               git clone ${scst_repo} ${ABT_TMPDIR}/scst &&		\
+               git clone -q ${scst_repo} ${ABT_TMPDIR}/scst &&		\
               cd ${ABT_TMPDIR}/scst && git reset --hard ${rev} );	\
           fi" &&
   runcmd ${logfile}							\
@@ -3,24 +3,25 @@
 ABT_DETAILS="x86_64"
 ABT_JOBS=5
 ABT_KERNELS="  \
-4.13.4	       \
+4.14           \
+4.13.12-nc     \
 4.12.14-nc     \
 4.11.12-nc     \
 4.10.17-nc     \
-4.9.45-nc      \
+4.9.61-nc      \
 4.8.17-nc      \
 4.7.10-nc      \
 4.6.7-nc       \
 4.5.7-nc       \
-4.4.34-nc      \
+4.4.65-nc      \
 4.3.6-nc       \
 4.2.8-nc       \
-4.1.35-nc      \
+4.1.38-nc      \
 4.0.9-nc       \
 3.19.8-nc      \
-3.18.44-nc     \
+3.18.51-nc     \
 3.17.8-nc      \
-3.16.39-nc     \
+3.16.41-nc     \
 3.15.10-nc     \
 3.14.79-nc     \
 3.13.11-nc     \
@@ -19,10 +19,14 @@ do
  esac
 done

-if [ $# -ge 3 ]; then
-  gzip -9 <"$3" >"$3.gz"
-  mutt -s "$1" -a "$3.gz" ${recipients} < "$2"
-  rm -f "$3.gz"
+if type mutt >/dev/null 2>&1; then
+  if [ $# -ge 3 ]; then
+    gzip -9 <"$3" >"$3.gz"
+    mutt -s "$1" -a "$3.gz" ${recipients} < "$2"
+    rm -f "$3.gz"
+  else
+    mutt -s "$1" ${recipients} < "$2"
+  fi
 else
-  mutt -s "$1" ${recipients} < "$2"
+  mail -s "$1" ${recipients} < "$2"
 fi
@@ -26,7 +26,11 @@
 #include <qla2x_tgt.h>
 #include <qla2x_tgt_def.h>

+#ifdef INSIDE_KERNEL_TREE
+#include <scst/scst_debug.h>
+#else
 #include <scst_debug.h>
+#endif

 /* Version numbers, the same as for the kernel */
 #define Q2T_VERSION(a, b, c, d)	(((a) << 030) + ((b) << 020) + (c) << 010 + (d))
@@ -2196,7 +2196,11 @@ qla24xx_bsg_timeout(struct bsg_job *bsg_job)
 						ql_log(ql_log_warn, vha, 0x7089,
 						    "mbx abort_command "
 						    "failed.\n");
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 12, 0)
+						scsi_req(bsg_job->req)->result =
+#else
 						bsg_job->req->errors =
+#endif
 #ifndef NEW_LIBFC_API
 						bsg_job->reply->result = -EIO;
 #else
@@ -2206,7 +2210,11 @@ qla24xx_bsg_timeout(struct bsg_job *bsg_job)
 						ql_dbg(ql_dbg_user, vha, 0x708a,
 						    "mbx abort_command "
 						    "success.\n");
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 12, 0)
+						scsi_req(bsg_job->req)->result =
+#else
 						bsg_job->req->errors =
+#endif
 #ifndef NEW_LIBFC_API
 						bsg_job->reply->result = 0;
 #else
@@ -2224,7 +2232,12 @@ qla24xx_bsg_timeout(struct bsg_job *bsg_job)
 #ifndef NEW_LIBFC_API
 	bsg_job->req->errors = bsg_job->reply->result = -ENXIO;
 #else
-	bsg_job->req->errors = bsg_reply->result = -ENXIO;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 12, 0)
+	scsi_req(bsg_job->req)->result =
+#else
+	bsg_job->req->errors =
+#endif
+	bsg_reply->result = -ENXIO;
 #endif
 	return 0;

@@ -2705,6 +2705,7 @@ qla24xx_enable_msix(struct qla_hw_data *ha, struct rsp_que *rsp)
 	for (i = 0; i < ha->msix_count; i++)
 		entries[i].entry = i;

+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 11, 0)
 	ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
 	if (ret) {
 		if (ret < MIN_MSIX_COUNT)
@@ -2726,6 +2727,24 @@ msix_failed:
 		}
 		ha->max_rsp_queues = ha->msix_count - 1;
 	}
+#else
+	ret = pci_enable_msix_range(ha->pdev,
+		    entries, MIN_MSIX_COUNT, ha->msix_count);
+	if (ret < 0) {
+		ql_log(ql_log_fatal, vha, 0x00c7,
+		    "MSI-X: Failed to enable support, "
+		    "giving   up -- %d/%d.\n",
+		    ha->msix_count, ret);
+		goto msix_out;
+	} else if (ret < ha->msix_count) {
+		ql_log(ql_log_warn, vha, 0x00c6,
+		    "MSI-X: Failed to enable support "
+		     "with %d vectors, using %d vectors.\n",
+		    ha->msix_count, ret);
+		ha->msix_count = ret;
+		ha->max_rsp_queues = ha->msix_count - 1;
+	}
+#endif
 	ha->msix_entries = kcalloc(ha->msix_count,
 				   sizeof(struct qla_msix_entry), GFP_KERNEL);
 	if (!ha->msix_entries) {
@@ -399,11 +399,12 @@ function handle_if(evaluated)
    if (debug)
      printf "/* debug specialize-patch: (e) %s */\n", evaluated
    evaluated = evaluate(evaluated)
+    sub("^+#if", "+#elif", evaluated);
    decision[if_nesting_level] = evaluated
    inv_decision[if_nesting_level] \
      = evaluate(sprintf("+#if %s && !%s", \
                         substr(inv_decision[if_nesting_level], 6), \
-                         substr(evaluated, 6)))
+                         substr(evaluated, 8)))
    if (debug)
      printf "/* debug specialize-patch: (f) %s / %s */\n", \
        decision[if_nesting_level], inv_decision[if_nesting_level]
@@ -1887,7 +1887,7 @@ information about ALUA support in Windows Server, see also:
  (http://msdn.microsoft.com/en-us/library/gg607458%28v=vs.85%29.aspx).

 Active/Non-Optimized via internal redirection
-...............................................
+.............................................

 The Active-Standby configuration is simple to understand and setup,
 however, it might have serious interoperability issues, because not all
@@ -1921,8 +1921,8 @@ served to initiator(s) (consider for simplicity that there is only one
 served device)

 5. Connect to this SCST device through this internal target from the
-passive node. Now you have a local SCSI device on the passive side
-pointing to the active node.
+passive node, for instance, using iSCSI. Now you have a local SCSI
+device on the passive side pointing to the active node.

 6. Export this local device to the initiator(s) using SCST
 *path-through* handler (scst_disk). Pass-though is needed to redirect
@@ -1954,8 +1954,122 @@ on the new passive node.

 6. Finish ALUA states change.

+Example using direct sysfs interface could look like:
+
+Active-Optimized node:
+
+modprobe scst
+modprobe scst_disk
+modprobe scst_vdisk
+
+# Main device, DRBD primary here
+echo "add_device aa filename=/dev/drbd1" >/sys/kernel/scst_tgt/handlers/vdisk_blockio/mgmt
+
+# Redirect device, not used here. Coming from connecting via iSCSI to the
+# corresponding redirect target on the other side.
+DEVICE=10:0:0:0
+echo add_device $DEVICE >/sys/kernel/scst_tgt/handlers/dev_disk/mgmt
+
+service iscsi-scst start
+
+# This is a regular, user-visible target
+echo "add_target iqn.2006-10.net.v:tgt " >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/rel_tgt_id
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/luns/mgmt
+
+# This is redirect target, 192.168.9.x is the redirect network
+echo "add_target iqn.2006-10.net.v:tgtR" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/rel_tgt_id
+echo "add_target_attribute iqn.2006-10.net.v:tgtR allowed_portal 192.168.9.1" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo "1" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/forwarding
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/luns/mgmt
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/enabled
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/enabled
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/enabled
+
+# ALUA config
+
+echo create aa >/sys/kernel/scst_tgt/device_groups/mgmt
+echo add aa >/sys/kernel/scst_tgt/device_groups/aa/devices/mgmt
+
+echo add tgt_a >/sys/kernel/scst_tgt/device_groups/aa/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/group_id
+echo active >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/state
+
+echo add tgt_n >/sys/kernel/scst_tgt/device_groups/aa/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt1 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/mgmt
+echo 2 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/iqn.2006-10.net.v:tgt1/rel_tgt_id
+echo 2 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/group_id
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/state
+
+Active-Non-Optimized node:
+
+modprobe scst
+modprobe scst_disk
+modprobe scst_vdisk
+
+# Main device, DRBD secondary, not used here
+echo "add_device aa filename=/dev/drbd1" >/sys/kernel/scst_tgt/handlers/vdisk_blockio/mgmt
+
+# Redirect device. Coming from connecting via iSCSI to the
+# corresponding redirect target on the other side.
+DEVICE=10:0:0:0
+echo add_device $DEVICE >/sys/kernel/scst_tgt/handlers/dev_disk/mgmt
+
+service iscsi-scst start
+
+echo "add_target iqn.2006-10.net.v:tgt1" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/rel_tgt_id
+echo "add $DEVICE 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+
+# Redirect target, 192.168.9.x is the redirect network
+echo "add_target iqn.2006-10.net.v:tgtR" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/rel_tgt_id
+echo "add_target_attribute iqn.2006-10.net.v:tgtR allowed_portal 192.168.9.2" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo "1" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/forwarding
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/luns/mgmt
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/enabled
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/enabled
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/enabled
+
+# ALUA config
+
+echo create $DEVICE >/sys/kernel/scst_tgt/device_groups/mgmt
+echo add $DEVICE >/sys/kernel/scst_tgt/device_groups/$DEVICE/devices/mgmt
+
+echo add tgt_a >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/iqn.2006-10.net.v:tgt/rel_tgt_id
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/group_id
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+
+echo add tgt_n >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/group_id
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
+ALUA state switch after DRBD primary-secondary transition:
+
+Ex-Optimized:
+
+echo "replace_no_ua $DEVICE 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
+Ex-Non-Optimized:
+
+echo "replace_no_ua aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
 If you have any questions, please read this above text at least 3 times
-before asking. It might be tricky to understand.
+before asking. It might be tricky to understand :-)
+

 VAAI
 ----
@@ -1740,7 +1740,7 @@ information about ALUA support in Windows Server, see also:
  (http://msdn.microsoft.com/en-us/library/gg607458%28v=vs.85%29.aspx).

 Active/Non-Optimized via internal redirection
-...............................................
+.............................................

 The Active-Standby configuration is simple to understand and setup,
 however, it might have serious interoperability issues, because not all
@@ -1774,8 +1774,8 @@ served to initiator(s) (consider for simplicity that there is only one
 served device)

 5. Connect to this SCST device through this internal target from the
-passive node. Now you have a local SCSI device on the passive side
-pointing to the active node.
+passive node, for instance, using iSCSI. Now you have a local SCSI
+device on the passive side pointing to the active node.

 6. Export this local device to the initiator(s) using SCST
 *path-through* handler (scst_disk). Pass-though is needed to redirect
@@ -1807,8 +1807,122 @@ on the new passive node.

 6. Finish ALUA states change.

+Example using direct sysfs interface could look like:
+
+Active-Optimized node:
+
+modprobe scst
+modprobe scst_disk
+modprobe scst_vdisk
+
+# Main device, DRBD primary here
+echo "add_device aa filename=/dev/drbd1" >/sys/kernel/scst_tgt/handlers/vdisk_blockio/mgmt
+
+# Redirect device, not used here. Coming from connecting via iSCSI to the
+# corresponding redirect target on the other side.
+DEVICE=10:0:0:0
+echo add_device $DEVICE >/sys/kernel/scst_tgt/handlers/dev_disk/mgmt
+
+service iscsi-scst start
+
+# This is a regular, user-visible target
+echo "add_target iqn.2006-10.net.v:tgt " >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/rel_tgt_id
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/luns/mgmt
+
+# This is redirect target, 192.168.9.x is the redirect network
+echo "add_target iqn.2006-10.net.v:tgtR" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/rel_tgt_id
+echo "add_target_attribute iqn.2006-10.net.v:tgtR allowed_portal 192.168.9.1" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo "1" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/forwarding
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/luns/mgmt
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt/enabled
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/enabled
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/enabled
+
+# ALUA config
+
+echo create aa >/sys/kernel/scst_tgt/device_groups/mgmt
+echo add aa >/sys/kernel/scst_tgt/device_groups/aa/devices/mgmt
+
+echo add tgt_a >/sys/kernel/scst_tgt/device_groups/aa/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/group_id
+echo active >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_a/state
+
+echo add tgt_n >/sys/kernel/scst_tgt/device_groups/aa/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt1 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/mgmt
+echo 2 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/iqn.2006-10.net.v:tgt1/rel_tgt_id
+echo 2 >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/group_id
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/aa/target_groups/tgt_n/state
+
+Active-Non-Optimized node:
+
+modprobe scst
+modprobe scst_disk
+modprobe scst_vdisk
+
+# Main device, DRBD secondary, not used here
+echo "add_device aa filename=/dev/drbd1" >/sys/kernel/scst_tgt/handlers/vdisk_blockio/mgmt
+
+# Redirect device. Coming from connecting via iSCSI to the
+# corresponding redirect target on the other side.
+DEVICE=10:0:0:0
+echo add_device $DEVICE >/sys/kernel/scst_tgt/handlers/dev_disk/mgmt
+
+service iscsi-scst start
+
+echo "add_target iqn.2006-10.net.v:tgt1" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/rel_tgt_id
+echo "add $DEVICE 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+
+# Redirect target, 192.168.9.x is the redirect network
+echo "add_target iqn.2006-10.net.v:tgtR" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo 2 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/rel_tgt_id
+echo "add_target_attribute iqn.2006-10.net.v:tgtR allowed_portal 192.168.9.2" >/sys/kernel/scst_tgt/targets/iscsi/mgmt
+echo "1" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/forwarding
+echo "add aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/luns/mgmt
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/enabled
+
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/enabled
+echo 1 >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgtR/enabled
+
+# ALUA config
+
+echo create $DEVICE >/sys/kernel/scst_tgt/device_groups/mgmt
+echo add $DEVICE >/sys/kernel/scst_tgt/device_groups/$DEVICE/devices/mgmt
+
+echo add tgt_a >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/iqn.2006-10.net.v:tgt/rel_tgt_id
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/group_id
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+
+echo add tgt_n >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/mgmt
+echo add iqn.2006-10.net.v:tgt1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/mgmt
+echo 1 >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/group_id
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
+ALUA state switch after DRBD primary-secondary transition:
+
+Ex-Optimized:
+
+echo "replace_no_ua $DEVICE 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
+Ex-Non-Optimized:
+
+echo "replace_no_ua aa 0" >/sys/kernel/scst_tgt/targets/iscsi/iqn.2006-10.net.v:tgt1/luns/mgmt
+echo nonoptimized >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_a/state
+echo active >/sys/kernel/scst_tgt/device_groups/$DEVICE/target_groups/tgt_n/state
+
 If you have any questions, please read this above text at least 3 times
-before asking. It might be tricky to understand.
+before asking. It might be tricky to understand :-)
+

 VAAI
 ----
@@ -60,6 +60,14 @@ static inline struct bio_set *bioset_create_backport(unsigned int pool_size,
 #define BIOSET_NEED_BVECS 0
 #endif

+/* See also commit 74d46992e0d9. */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 0)
+static inline void bio_set_dev(struct bio *bio, struct block_device *bdev)
+{
+	bio->bi_bdev = bdev;
+}
+#endif
+
 /* <linux/blkdev.h> */

 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31)
@@ -239,27 +247,6 @@ static inline struct inode *file_inode(const struct file *f)
 }
 #endif

-#if (!defined(CONFIG_SUSE_KERNEL) &&				\
-	LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)) ||	\
-	LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
-static inline ssize_t vfs_readv_backport(struct file *file,
-					 const struct iovec __user *vec,
-					 unsigned long vlen, loff_t *pos,
-					 int flags)
-{
-	return vfs_readv(file, vec, vlen, pos);
-}
-static inline ssize_t vfs_writev_backport(struct file *file,
-					  const struct iovec __user *vec,
-					  unsigned long vlen, loff_t *pos,
-					  int flags)
-{
-	return vfs_writev(file, vec, vlen, pos);
-}
-#define vfs_readv vfs_readv_backport
-#define vfs_writev vfs_writev_backport
-#endif
-
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 35)
 static inline int vfs_fsync_backport(struct file *file, int datasync)
 {
@@ -759,4 +746,32 @@ static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
 }
 #endif

+/* <scsi/scsi_request.h> */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 11, 0)
+static inline struct request *scsi_req(struct request *rq)
+{
+	return rq;
+}
+
+static inline void scsi_req_init(struct request *rq)
+{
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 16, 0)
+	rq->cmd_type = REQ_TYPE_BLOCK_PC;
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31)
+	rq->data_len = 0;
+	rq->sector = (sector_t) -1;
+#else
+	rq->__data_len = 0;
+	rq->__sector = (sector_t) -1;
+#endif
+	rq->bio = rq->biotail = NULL;
+	memset(rq->__cmd, 0, sizeof(rq->__cmd));
+	rq->cmd = rq->__cmd;
+#else
+	return blk_rq_set_block_pc(rq);
+#endif
+}
+#endif
+
 #endif /* _SCST_BACKPORT_H_ */
@@ -5536,7 +5536,7 @@ static inline void prepare_to_wait_exclusive_head(struct wait_queue_head *wq_hea
 *
 * Caller must hold lock of type @lock_type on @lock.
 */
-#define wait_event_locked(wq, condition, lock_type, lock)		\
+#define wait_event_locked(wq, condition, lock_type, lock) do {		\
 if (!(condition)) {							\
 	DEFINE_WAIT(__wait);						\
 									\
@@ -5550,7 +5550,8 @@ if (!(condition)) {							\
 		spin_ ## lock_type(&(lock));				\
 	} while (!(condition));						\
 	finish_wait(&(wq), &__wait);					\
-}
+}									\
+} while (0)

 /* Only use get_unaligned_be24() if reading p - 1 is allowed. */
 static inline uint32_t get_unaligned_be24(const uint8_t *const p)
@@ -5712,9 +5713,16 @@ struct scst_data_descriptor {
 	uint64_t sdd_blocks;
 };

+ssize_t scst_read(struct file *file, void *buf, size_t count, loff_t *pos);
+ssize_t scst_write(struct file *file, const void *buf, size_t count,
+		   loff_t *pos);
+ssize_t scst_readv(struct file *file, const struct iovec *vec,
+		   unsigned long vlen, loff_t *pos);
+ssize_t scst_writev(struct file *file, const struct iovec *vec,
+		    unsigned long vlen, loff_t *pos);
 void scst_write_same(struct scst_cmd *cmd, struct scst_data_descriptor *where);
 int scst_scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
-		      int data_direction, void *buffer, unsigned bufflen,
+		      int data_direction, void *buffer, unsigned int bufflen,
 		      unsigned char *sense, int timeout, int retries,
 		      u64 flags);

@@ -2112,8 +2112,7 @@ static int vdisk_format_dif(struct scst_cmd *cmd, uint64_t start_lba,
 			full_len, (long long)loff);

 		/* WRITE */
-		err = vfs_writev(fd, (struct iovec __force __user *)iv,
-				 iv_count, &loff, 0);
+		err = scst_writev(fd, iv, iv_count, &loff);
 		if (err < 0) {
 			PRINT_ERROR("Formatting DIF write() returned %lld from "
 				"%zd", err, full_len);
@@ -5962,8 +5961,7 @@ static int vdev_read_dif_tags(struct vdisk_cmd_params *p)
 			iv_count, full_len, (long long)loff);

 		/* READ */
-		err = vfs_readv(fd, (struct iovec __force __user *)iv, iv_count,
-				&loff, 0);
+		err = scst_readv(fd, iv, iv_count, &loff);
 		if ((err < 0) || (err < full_len)) {
 			unsigned long flags;

@@ -6091,8 +6089,7 @@ restart:
 		TRACE_DBG("Writing DIF: eiv_count %d, full_len %zd", eiv_count, full_len);

 		/* WRITE */
-		err = vfs_writev(fd, (struct iovec __force __user *)eiv,
-				 eiv_count, &loff, 0);
+		err = scst_writev(fd, eiv, eiv_count, &loff);
 		if (err < 0) {
 			unsigned long flags;

@@ -6233,8 +6230,7 @@ static enum compl_status_e fileio_exec_read(struct vdisk_cmd_params *p)
 		TRACE_DBG("Reading iv_count %d, full_len %zd", iv_count, full_len);

 		/* READ */
-		err = vfs_readv(fd, (struct iovec __force __user *)iv, iv_count,
-				&loff, 0);
+		err = scst_readv(fd, iv, iv_count, &loff);
 		if ((err < 0) || (err < full_len)) {
 			PRINT_ERROR("readv() returned %lld from %zd",
 				    (unsigned long long int)err,
@@ -6427,8 +6423,7 @@ restart:
 		TRACE_DBG("Writing: eiv_count %d, full_len %zd", eiv_count, full_len);

 		/* WRITE */
-		err = vfs_writev(fd, (struct iovec __force __user *)eiv,
-				 eiv_count, &loff, 0);
+		err = scst_writev(fd, eiv, eiv_count, &loff);
 		if (err < 0) {
 			PRINT_ERROR("write() returned %lld from %zd",
 				    (unsigned long long int)err,
@@ -6919,7 +6914,7 @@ static void blockio_exec_rw(struct vdisk_cmd_params *p, bool write, bool fua)
 #else
 				bio->bi_sector = lba_start0 << (block_shift - 9);
 #endif
-				bio->bi_bdev = bdev;
+				bio_set_dev(bio, bdev);
 				bio->bi_private = blockio_work;
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 30)) && (LINUX_VERSION_CODE <= KERNEL_VERSION(3, 6, 0))
 				bio->bi_destructor = blockio_bio_destructor;
@@ -7103,7 +7098,7 @@ static int vdisk_blockio_flush(struct block_device *bdev, gfp_t gfp_mask,
 		}
 		bio->bi_end_io = vdev_flush_end_io;
 		bio->bi_private = cmd;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 #if (!defined(CONFIG_SUSE_KERNEL) &&			\
 	LINUX_VERSION_CODE < KERNEL_VERSION(4, 8, 0)) || \
 	LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
@@ -7262,7 +7257,7 @@ static ssize_t blockio_read_sync(struct scst_vdisk_dev *virt_dev, void *buf,
 #else
 	bio_set_op_attrs(bio, REQ_OP_READ, REQ_SYNC);
 #endif
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	bio->bi_end_io = blockio_end_sync_io;
 	bio->bi_private = &s;
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 30)) && (LINUX_VERSION_CODE <= KERNEL_VERSION(3, 6, 0))
@@ -7325,7 +7320,7 @@ static ssize_t fileio_read_sync(struct file *fd, void *buf, size_t len,

 	old_fs = get_fs();
 	set_fs(get_ds());
-	ret = vfs_read(fd, (char __force __user *)buf, len, loff);
+	ret = scst_read(fd, buf, len, loff);
 	set_fs(old_fs);

 	return ret;
@@ -511,7 +511,7 @@ static int scst_read_file(const char *path, char *buf, int buf_len)
 		goto out;
 	}
 	pos = 0;
-	ret = vfs_read(f, (char __force __user *)buf, buf_len, &pos);
+	ret = scst_read(f, buf, buf_len, &pos);
 	if (ret >= 0)
 		buf[min(ret, buf_len - 1)] = '\0';
 	filp_close(f, NULL);
@@ -5861,6 +5861,101 @@ static void scst_complete_request_sense(struct scst_cmd *req_cmd)
 	return;
 }

+ssize_t scst_read(struct file *file, void *buf, size_t count, loff_t *pos)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
+	struct iovec iov = {
+		.iov_base = (void __force __user *)buf,
+		.iov_len = count
+	};
+
+	return scst_readv(file, &iov, 1, pos);
+#else
+	return vfs_read(file, (void __force __user *)buf, count, pos);
+#endif
+}
+EXPORT_SYMBOL(scst_read);
+
+ssize_t scst_write(struct file *file, const void *buf, size_t count,
+		   loff_t *pos)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
+	struct iovec iov = {
+		.iov_base = (void __force __user *)buf,
+		.iov_len = count
+	};
+
+	return scst_writev(file, &iov, 1, pos);
+#else
+	return vfs_write(file, (void __force __user *)buf, count, pos);
+#endif
+}
+EXPORT_SYMBOL(scst_write);
+
+ssize_t scst_readv(struct file *file, const struct iovec *vec,
+		   unsigned long vlen, loff_t *pos)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	ssize_t ret;
+
+	ret = import_iovec(READ, (const struct iovec __force __user *)vec, vlen,
+			   ARRAY_SIZE(iovstack), &iov, &iter);
+	if (ret < 0)
+		return ret;
+	ret = vfs_iter_read(file, &iter, pos, 0);
+	kfree(iov);
+	return ret;
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0) ||	\
+	(defined(CONFIG_SUSE_KERNEL) &&			\
+	LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0))
+	return vfs_readv(file, (const struct iovec __user *)vec, vlen, pos, 0);
+#else
+	return vfs_readv(file, (const struct iovec __user *)vec, vlen, pos);
+#endif
+}
+EXPORT_SYMBOL(scst_readv);
+
+/**
+ * scst_writev - write a buffer to a file
+ * @file: File to write to.
+ * @vec:  Pointer to first element of struct iovec array.
+ * @vlen: Number of elements of the iovec array.
+ * @pos:  Position in @file where to start writing.
+ *
+ * Note: although @vec->iov_base has type void __user*, it points at kernel
+ * data and not at data in user space.
+ */
+ssize_t scst_writev(struct file *file, const struct iovec *vec,
+		    unsigned long vlen, loff_t *pos)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 14, 0)
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	ssize_t ret;
+
+	ret = import_iovec(WRITE, (const struct iovec __force __user *)vec,
+			   vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	if (ret < 0)
+		return ret;
+	file_start_write(file);
+	ret = vfs_iter_write(file, &iter, pos, 0);
+	file_end_write(file);
+	kfree(iov);
+	return ret;
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0) ||	\
+	(defined(CONFIG_SUSE_KERNEL) &&			\
+	LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0))
+	return vfs_writev(file, (const struct iovec __user *)vec, vlen, pos, 0);
+#else
+	return vfs_writev(file, (const struct iovec __user *)vec, vlen, pos);
+#endif
+}
+EXPORT_SYMBOL(scst_writev);
+
 struct scst_ws_sg_tail {
 	struct scatterlist *sg;
 	int sg_cnt;
@@ -6780,7 +6875,7 @@ out:
 }

 int scst_scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
-		      int data_direction, void *buffer, unsigned bufflen,
+		      int data_direction, void *buffer, unsigned int bufflen,
 		      unsigned char *sense, int timeout, int retries, u64 flags)
 {
 	return scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense,
@@ -7862,11 +7957,7 @@ static struct request *blk_make_request(struct request_queue *q,
 	if (IS_ERR(rq))
 		return rq;

-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
 	scsi_req_init(scsi_req(rq));
-#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
-	scsi_req_init(rq);
-#endif
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
 	rq->cmd_flags = bio_data_dir(bio) == READ ? REQ_OP_SCSI_IN :
 		REQ_OP_SCSI_OUT;
@@ -8098,15 +8189,9 @@ static struct request *blk_map_kern_sg(struct request_queue *q,
 		if (unlikely(!rq))
 			return ERR_PTR(-ENOMEM);

-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 13, 0)
 		scsi_req_init(scsi_req(rq));
-#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
-		scsi_req_init(rq);
-#endif
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
 		rq->cmd_flags = reading ? REQ_OP_SCSI_IN : REQ_OP_SCSI_OUT;
-#else
-		blk_rq_set_block_pc(rq);
 #endif
 		goto out;
 	}
@@ -8401,12 +8486,7 @@ int scst_scsi_exec_async(struct scst_cmd *cmd, void *data,
 	sioc->data = data;
 	sioc->done = done;

-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0)
 	req = scsi_req(rq);
-#else
-	req = rq;
-#endif
-
 	req->cmd_len = cmd_len;
 	if (req->cmd_len <= BLK_MAX_CDB) {
 		memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
@@ -14872,14 +14952,14 @@ int scst_copy_file(const char *src, const char *dest)
 	}

 	pos = 0;
-	res = vfs_read(file_src, (void __force __user *)buf, file_size, &pos);
+	res = scst_read(file_src, buf, file_size, &pos);
 	if (res != file_size) {
 		PRINT_ERROR("Unable to read file '%s' - error %d", src, res);
 		goto out_skip;
 	}

 	pos = 0;
-	res = vfs_write(file_dest, (void __force __user *)buf, file_size, &pos);
+	res = scst_write(file_dest, buf, file_size, &pos);
 	if (res != file_size) {
 		PRINT_ERROR("Unable to write to '%s' - error %d", dest, res);
 		goto out_skip;
@@ -14973,7 +15053,7 @@ int scst_write_file_transactional(const char *name, const char *name1,

 	pos = signature_len+1;

-	res = vfs_write(file, (void const __force __user *)buf, size, &pos);
+	res = scst_write(file, buf, size, &pos);
 	if (res != size)
 		goto write_error;

@@ -14984,11 +15064,11 @@ int scst_write_file_transactional(const char *name, const char *name1,
 	}

 	pos = 0;
-	res = vfs_write(file, (void const __force __user *)signature, signature_len, &pos);
+	res = scst_write(file, signature, signature_len, &pos);
 	if (res != signature_len)
 		goto write_error;

-	res = vfs_write(file, (void __force __user *)&n, sizeof(n), &pos);
+	res = scst_write(file, &n, sizeof(n), &pos);
 	if (res != sizeof(n))
 		goto write_error;

@@ -15070,7 +15150,7 @@ static int __scst_read_file_transactional(const char *file_name,
 	}

 	pos = 0;
-	res = vfs_read(file, (void __force __user *)buf, file_size, &pos);
+	res = scst_read(file, buf, file_size, &pos);
 	if (res != file_size) {
 		PRINT_ERROR("Unable to read file '%s' - error %d", file_name, res);
 		if (res > 0)
@@ -720,7 +720,7 @@ static int scst_pr_do_load_device_file(struct scst_device *dev,
 	}

 	pos = 0;
-	rc = vfs_read(file, (void __force __user *)buf, file_size, &pos);
+	rc = scst_read(file, buf, file_size, &pos);
 	if (rc != file_size) {
 		PRINT_ERROR("Unable to read file '%s' - error %d", file_name,
 			rc);
@@ -925,7 +925,7 @@ void scst_pr_sync_device_file(struct scst_device *dev)
 	 */
 	sign = 0;
 	pos = 0;
-	res = vfs_write(file, (void __force __user *)&sign, sizeof(sign), &pos);
+	res = scst_write(file, &sign, sizeof(sign), &pos);
 	if (res != sizeof(sign))
 		goto write_error;

@@ -933,7 +933,7 @@ void scst_pr_sync_device_file(struct scst_device *dev)
 	 * version
 	 */
 	version = SCST_PR_FILE_VERSION;
-	res = vfs_write(file, (void __force __user *)&version, sizeof(version), &pos);
+	res = scst_write(file, &version, sizeof(version), &pos);
 	if (res != sizeof(version))
 		goto write_error;

@@ -941,7 +941,7 @@ void scst_pr_sync_device_file(struct scst_device *dev)
 	 * APTPL
 	 */
 	aptpl = dev->pr_aptpl;
-	res = vfs_write(file, (void __force __user *)&aptpl, sizeof(aptpl), &pos);
+	res = scst_write(file, &aptpl, sizeof(aptpl), &pos);
 	if (res != sizeof(aptpl))
 		goto write_error;

@@ -949,15 +949,15 @@ void scst_pr_sync_device_file(struct scst_device *dev)
 	 * reservation
 	 */
 	pr_is_set = dev->pr_is_set;
-	res = vfs_write(file, (void __force __user *)&pr_is_set, sizeof(pr_is_set), &pos);
+	res = scst_write(file, &pr_is_set, sizeof(pr_is_set), &pos);
 	if (res != sizeof(pr_is_set))
 		goto write_error;

-	res = vfs_write(file, (void __force __user *)&dev->pr_type, sizeof(dev->pr_type), &pos);
+	res = scst_write(file, &dev->pr_type, sizeof(dev->pr_type), &pos);
 	if (res != sizeof(dev->pr_type))
 		goto write_error;

-	res = vfs_write(file, (void __force __user *)&dev->pr_scope, sizeof(dev->pr_scope), &pos);
+	res = scst_write(file, &dev->pr_scope, sizeof(dev->pr_scope), &pos);
 	if (res != sizeof(dev->pr_scope))
 		goto write_error;

@@ -971,23 +971,23 @@ void scst_pr_sync_device_file(struct scst_device *dev)

 		is_holder = (dev->pr_holder == reg);

-		res = vfs_write(file, (void __force __user *)&is_holder,
+		res = scst_write(file, &is_holder,
 				sizeof(is_holder), &pos);
 		if (res != sizeof(is_holder))
 			goto write_error;

 		size = scst_tid_size(reg->transport_id);
-		res = vfs_write(file, (void __force __user *)reg->transport_id,
+		res = scst_write(file, reg->transport_id,
 				size, &pos);
 		if (res != size)
 			goto write_error;

-		res = vfs_write(file, (void __force __user *)&reg->key,
+		res = scst_write(file, &reg->key,
 				sizeof(reg->key), &pos);
 		if (res != sizeof(reg->key))
 			goto write_error;

-		res = vfs_write(file, (void __force __user *)&reg->rel_tgt_id,
+		res = scst_write(file, &reg->rel_tgt_id,
 				sizeof(reg->rel_tgt_id), &pos);
 		if (res != sizeof(reg->rel_tgt_id))
 			goto write_error;
@@ -1001,7 +1001,7 @@ void scst_pr_sync_device_file(struct scst_device *dev)

 	sign = SCST_PR_FILE_SIGN;
 	pos = 0;
-	res = vfs_write(file, (void __force __user *)&sign, sizeof(sign), &pos);
+	res = scst_write(file, &sign, sizeof(sign), &pos);
 	if (res != sizeof(sign))
 		goto write_error;

@@ -3836,8 +3836,8 @@ static int scst_exec_check_sn(struct scst_cmd **active_cmd)

 				/* dev->qerr can be changed behind our back */
 				q = cmd->dev->qerr;
-				/* ACCESS_ONCE doesn't work for bit fields */
-				qerr = ACCESS_ONCE(q);
+				/* READ_ONCE doesn't work for bit fields */
+				qerr = READ_ONCE(q);

 				switch (qerr) {
 				case SCST_QERR_2_RESERVED:
@@ -4477,12 +4477,7 @@ static void srpt_add_one(struct ib_device *device)

 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
 			      srpt_event_handler);
-	ret = ib_register_event_handler(&sdev->event_handler);
-	if (ret) {
-		pr_err("ib_register_event_handler() failed: %d\n", ret);
-		goto err_cm;
-	}
-
+	ib_register_event_handler(&sdev->event_handler);
 	atomic_inc(&srpt_device_count);
 out:
 	ib_set_client_data(device, &srpt_client, sdev);