diff --git a/sys/compat/linuxkpi/common/include/linux/sysfs.h b/sys/compat/linuxkpi/common/include/linux/sysfs.h
index b9689a367c90..9d19dd50dbbc 100644
--- a/sys/compat/linuxkpi/common/include/linux/sysfs.h
+++ b/sys/compat/linuxkpi/common/include/linux/sysfs.h
@@ -1,319 +1,337 @@
 /*-
  * Copyright (c) 2010 Isilon Systems, Inc.
  * Copyright (c) 2010 iX Systems, Inc.
  * Copyright (c) 2010 Panasas, Inc.
  * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice unmodified, this list of conditions, and the following
  *    disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD$
  */
 #ifndef	_LINUXKPI_LINUX_SYSFS_H_
 #define	_LINUXKPI_LINUX_SYSFS_H_
 
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #include <sys/errno.h>
 
 #include <linux/kobject.h>
 #include <linux/stringify.h>
 #include <linux/mm.h>
 
 struct sysfs_ops {
 	ssize_t (*show)(struct kobject *, struct attribute *, char *);
 	ssize_t (*store)(struct kobject *, struct attribute *, const char *,
 	    size_t);
 };
 
 struct attribute_group {
 	const char		*name;
 	mode_t			(*is_visible)(struct kobject *,
 				    struct attribute *, int);
 	struct attribute	**attrs;
 };
 
 #define	__ATTR(_name, _mode, _show, _store) {				\
 	.attr = { .name = __stringify(_name), .mode = _mode },		\
 	.show = _show, .store  = _store,				\
 }
 #define	__ATTR_RO(_name)	__ATTR(_name, 0444, _name##_show, NULL)
 #define	__ATTR_WO(_name)	__ATTR(_name, 0200, NULL, _name##_store)
 #define	__ATTR_RW(_name)	__ATTR(_name, 0644, _name##_show, _name##_store)
 #define	__ATTR_NULL	{ .attr = { .name = NULL } }
 
 #define	ATTRIBUTE_GROUPS(_name)						\
 	static struct attribute_group _name##_group = {			\
 		.name = __stringify(_name),				\
 		.attrs = _name##_attrs,					\
 	};								\
 	static const struct attribute_group *_name##_groups[] = {	\
 		&_name##_group,						\
 		NULL,							\
 	}
 
 /*
  * Handle our generic '\0' terminated 'C' string.
  * Two cases:
  *      a variable string:  point arg1 at it, arg2 is max length.
  *      a constant string:  point arg1 at it, arg2 is zero.
  */
 
 static inline int
 sysctl_handle_attr(SYSCTL_HANDLER_ARGS)
 {
 	struct kobject *kobj;
 	struct attribute *attr;
 	const struct sysfs_ops *ops;
 	char *buf;
 	int error;
 	ssize_t len;
 
 	kobj = arg1;
 	attr = (struct attribute *)(intptr_t)arg2;
 	if (kobj->ktype == NULL || kobj->ktype->sysfs_ops == NULL)
 		return (ENODEV);
 	buf = (char *)get_zeroed_page(GFP_KERNEL);
 	if (buf == NULL)
 		return (ENOMEM);
 	ops = kobj->ktype->sysfs_ops;
 	if (ops->show) {
 		len = ops->show(kobj, attr, buf);
 		/*
 		 * It's valid to not have a 'show' so just return an
 		 * empty string.
 		 */
 		if (len < 0) {
 			error = -len;
 			if (error != EIO)
 				goto out;
 			buf[0] = '\0';
 		} else if (len) {
 			len--;
 			if (len >= PAGE_SIZE)
 				len = PAGE_SIZE - 1;
 			/* Trim trailing newline. */
 			buf[len] = '\0';
 		}
 	}
 
 	/* Leave one trailing byte to append a newline. */
 	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
 	if (error != 0 || req->newptr == NULL || ops->store == NULL)
 		goto out;
 	len = strlcat(buf, "\n", PAGE_SIZE);
 	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
 	len = ops->store(kobj, attr, buf, len);
 	if (len < 0)
 		error = -len;
 out:
 	free_page((unsigned long)buf);
 
 	return (error);
 }
 
 static inline int
 sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
 {
 	struct sysctl_oid *oid;
 
 	oid = SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
 	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
 	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
 	if (!oid) {
 		return (-ENOMEM);
 	}
 
 	return (0);
 }
 
 static inline void
 sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
 {
 
 	if (kobj->oidp)
 		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
 }
 
 static inline int
 sysfs_create_files(struct kobject *kobj, const struct attribute * const *attrs)
 {
 	int error = 0;
 	int i;
 
 	for (i = 0; attrs[i] && !error; i++)
 		error = sysfs_create_file(kobj, attrs[i]);
 	while (error && --i >= 0)
 		sysfs_remove_file(kobj, attrs[i]);
 
 	return (error);
 }
 
 static inline void
 sysfs_remove_files(struct kobject *kobj, const struct attribute * const *attrs)
 {
 	int i;
 
 	for (i = 0; attrs[i]; i++)
 		sysfs_remove_file(kobj, attrs[i]);
 }
 
 static inline int
 sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
 {
 	struct attribute **attr;
 	struct sysctl_oid *oidp;
 
 	/* Don't create the group node if grp->name is undefined. */
 	if (grp->name)
 		oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
 		    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
 	else
 		oidp = kobj->oidp;
 	for (attr = grp->attrs; *attr != NULL; attr++) {
 		SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
 		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
 		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
 	}
 
 	return (0);
 }
 
 static inline void
 sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
 {
 
 	if (kobj->oidp)
 		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
 }
 
 static inline int
 sysfs_create_groups(struct kobject *kobj, const struct attribute_group **grps)
 {
 	int error = 0;
 	int i;
 
 	if (grps == NULL)
 		goto done;
 	for (i = 0; grps[i] && !error; i++)
 		error = sysfs_create_group(kobj, grps[i]);
 	while (error && --i >= 0)
 		sysfs_remove_group(kobj, grps[i]);
 done:
 	return (error);
 }
 
 static inline void
 sysfs_remove_groups(struct kobject *kobj, const struct attribute_group **grps)
 {
 	int i;
 
 	if (grps == NULL)
 		return;
 	for (i = 0; grps[i]; i++)
 		sysfs_remove_group(kobj, grps[i]);
 }
 
 static inline int
 sysfs_merge_group(struct kobject *kobj, const struct attribute_group *grp)
 {
 
 	/* Really expected behavior is to return failure if group exists. */
 	return (sysfs_create_group(kobj, grp));
 }
 
 static inline void
 sysfs_unmerge_group(struct kobject *kobj, const struct attribute_group *grp)
 {
 	struct attribute **attr;
 	struct sysctl_oid *oidp;
 
 	SYSCTL_FOREACH(oidp, SYSCTL_CHILDREN(kobj->oidp)) {
 		if (strcmp(oidp->oid_name, grp->name) != 0)
 			continue;
 		for (attr = grp->attrs; *attr != NULL; attr++) {
 			sysctl_remove_name(oidp, (*attr)->name, 1, 1);
 		}
 	}
 }
 
 static inline int
 sysfs_create_dir(struct kobject *kobj)
 {
 	struct sysctl_oid *oid;
 
 	oid = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
 	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
 	if (!oid) {
 		return (-ENOMEM);
 	}
 	kobj->oidp = oid;
 
 	return (0);
 }
 
 static inline void
 sysfs_remove_dir(struct kobject *kobj)
 {
 
 	if (kobj->oidp == NULL)
 		return;
 	sysctl_remove_oid(kobj->oidp, 1, 1);
 }
 
 static inline bool
 sysfs_streq(const char *s1, const char *s2)
 {
 	int l1, l2;
 
 	l1 = strlen(s1);
 	l2 = strlen(s2);
 
 	if (l1 != 0 && s1[l1-1] == '\n')
 		l1--;
 	if (l2 != 0 && s2[l2-1] == '\n')
 		l2--;
 
 	return (l1 == l2 && strncmp(s1, s2, l1) == 0);
 }
 
 static inline int
 sysfs_emit(char *buf, const char *fmt, ...)
 {
 	va_list args;
 	int i;
 
 	if (!buf || offset_in_page(buf)) {
 		pr_warn("invalid sysfs_emit: buf:%p\n", buf);
 		return (0);
 	}
 
 	va_start(args, fmt);
 	i = vscnprintf(buf, PAGE_SIZE, fmt, args);
 	va_end(args);
 
 	return (i);
 }
 
+static inline int
+sysfs_emit_at(char *buf, int at, const char *fmt, ...)
+{
+	va_list args;
+	int i;
+
+	if (!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE) {
+		pr_warn("invalid sysfs_emit: buf:%p at:%d\n", buf, at);
+		return (0);
+	}
+
+	va_start(args, fmt);
+	i = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
+	va_end(args);
+
+	return (i);
+}
+
 #define sysfs_attr_init(attr) do {} while(0)
 
 #endif	/* _LINUXKPI_LINUX_SYSFS_H_ */