drivers/staging/lustre/lnet/libcfs/libcfs_string.c - arm/linux - Git at Google

 /*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 only,
  * as published by the Free Software Foundation.
  *
  * 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 version 2 for more details (a copy is included
  * in the LICENSE file that accompanied this code).
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
  * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
  * Copyright (c) 2012, 2015 Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * String manipulation functions.
  *
  * libcfs/libcfs/libcfs_string.c
  *
  * Author: Nathan Rutman <nathan.rutman@sun.com>
  */

 #include <linux/libcfs/libcfs.h>

 /* Convert a text string to a bitmask */
 int cfs_str2mask(const char *str, const char *(*bit2str)(int bit),
 		 int *oldmask, int minmask, int allmask)
 {
 	const char *debugstr;
 	char op = '\0';
 	int newmask = minmask, i, len, found = 0;

 	/* <str> must be a list of tokens separated by whitespace
 	 * and optionally an operator ('+' or '-').  If an operator
 	 * appears first in <str>, '*oldmask' is used as the starting point
 	 * (relative), otherwise minmask is used (absolute).  An operator
 	 * applies to all following tokens up to the next operator.
 	 */
 	while (*str != '\0') {
 		while (isspace(*str))
 			str++;
 		if (*str == '\0')
 			break;
 		if (*str == '+' || *str == '-') {
 			op = *str++;
 			if (!found)
 				/* only if first token is relative */
 				newmask = *oldmask;
 			while (isspace(*str))
 				str++;
 			if (*str == '\0')  /* trailing op */
 				return -EINVAL;
 		}

 		/* find token length */
 		len = 0;
 		while (str[len] != '\0' && !isspace(str[len]) &&
 		       str[len] != '+' && str[len] != '-')
 			len++;

 		/* match token */
 		found = 0;
 		for (i = 0; i < 32; i++) {
 			debugstr = bit2str(i);
 			if (debugstr && strlen(debugstr) == len &&
 			    !strncasecmp(str, debugstr, len)) {
 				if (op == '-')
 					newmask &= ~(1 << i);
 				else
 					newmask |= (1 << i);
 				found = 1;
 				break;
 			}
 		}
 		if (!found && len == 3 &&
 		    !strncasecmp(str, "ALL", len)) {
 			if (op == '-')
 				newmask = minmask;
 			else
 				newmask = allmask;
 			found = 1;
 		}
 		if (!found) {
 			CWARN("unknown mask '%.*s'.\n"
 			      "mask usage: [+|-]<all|type> ...\n", len, str);
 			return -EINVAL;
 		}
 		str += len;
 	}

 	*oldmask = newmask;
 	return 0;
 }

 /* get the first string out of @str */
 char *cfs_firststr(char *str, size_t size)
 {
 	size_t i = 0;
 	char *end;

 	/* trim leading spaces */
 	while (i < size && *str && isspace(*str)) {
 		++i;
 		++str;
 	}

 	/* string with all spaces */
 	if (*str == '\0')
 		goto out;

 	end = str;
 	while (i < size && *end != '\0' && !isspace(*end)) {
 		++i;
 		++end;
 	}

 	*end = '\0';
 out:
 	return str;
 }
 EXPORT_SYMBOL(cfs_firststr);

 char *
 cfs_trimwhite(char *str)
 {
 	char *end;

 	while (isspace(*str))
 		str++;

 	end = str + strlen(str);
 	while (end > str) {
 		if (!isspace(end[-1]))
 			break;
 		end--;
 	}

 	*end = 0;
 	return str;
 }
 EXPORT_SYMBOL(cfs_trimwhite);

 /**
  * Extracts tokens from strings.
  *
  * Looks for \a delim in string \a next, sets \a res to point to
  * substring before the delimiter, sets \a next right after the found
  * delimiter.
  *
  * \retval 1 if \a res points to a string of non-whitespace characters
  * \retval 0 otherwise
  */
 int
 cfs_gettok(struct cfs_lstr *next, char delim, struct cfs_lstr *res)
 {
 	char *end;

 	if (!next->ls_str)
 		return 0;

 	/* skip leading white spaces */
 	while (next->ls_len) {
 		if (!isspace(*next->ls_str))
 			break;
 		next->ls_str++;
 		next->ls_len--;
 	}

 	if (!next->ls_len) /* whitespaces only */
 		return 0;

 	if (*next->ls_str == delim) {
 		/* first non-writespace is the delimiter */
 		return 0;
 	}

 	res->ls_str = next->ls_str;
 	end = memchr(next->ls_str, delim, next->ls_len);
 	if (!end) {
 		/* there is no the delimeter in the string */
 		end = next->ls_str + next->ls_len;
 		next->ls_str = NULL;
 	} else {
 		next->ls_str = end + 1;
 		next->ls_len -= (end - res->ls_str + 1);
 	}

 	/* skip ending whitespaces */
 	while (--end != res->ls_str) {
 		if (!isspace(*end))
 			break;
 	}

 	res->ls_len = end - res->ls_str + 1;
 	return 1;
 }
 EXPORT_SYMBOL(cfs_gettok);

 /**
  * Converts string to integer.
  *
  * Accepts decimal and hexadecimal number recordings.
  *
  * \retval 1 if first \a nob chars of \a str convert to decimal or
  * hexadecimal integer in the range [\a min, \a max]
  * \retval 0 otherwise
  */
 int
 cfs_str2num_check(char *str, int nob, unsigned int *num,
 		  unsigned int min, unsigned int max)
 {
 	bool all_numbers = true;
 	char *endp, cache;
 	int rc;

 	/**
 	 * kstrouint can only handle strings composed
 	 * of only numbers. We need to scan the string
 	 * passed in for the first non-digit character
 	 * and end the string at that location. If we
 	 * don't find any non-digit character we still
 	 * need to place a '\0' at position nob since
 	 * we are not interested in the rest of the
 	 * string which is longer than nob in size.
 	 * After we are done the character at the
 	 * position we placed '\0' must be restored.
 	 */
 	for (endp = str; endp < str + nob; endp++) {
 		if (!isdigit(*endp)) {
 			all_numbers = false;
 			break;
 		}
 	}
 	cache = *endp;
 	*endp = '\0';

 	rc = kstrtouint(str, 10, num);
 	*endp = cache;
 	if (rc || !all_numbers)
 		return 0;

 	return (*num >= min && *num <= max);
 }
 EXPORT_SYMBOL(cfs_str2num_check);

 /**
  * Parses \<range_expr\> token of the syntax. If \a bracketed is false,
  * \a src should only have a single token which can be \<number\> or  \*
  *
  * \retval pointer to allocated range_expr and initialized
  * range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
  `* src parses to
  * \<number\> |
  * \<number\> '-' \<number\> |
  * \<number\> '-' \<number\> '/' \<number\>
  * \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
  * -ENOMEM will be returned.
  */
 static int
 cfs_range_expr_parse(struct cfs_lstr *src, unsigned int min, unsigned int max,
 		     int bracketed, struct cfs_range_expr **expr)
 {
 	struct cfs_range_expr *re;
 	struct cfs_lstr tok;

 	LIBCFS_ALLOC(re, sizeof(*re));
 	if (!re)
 		return -ENOMEM;

 	if (src->ls_len == 1 && src->ls_str[0] == '*') {
 		re->re_lo = min;
 		re->re_hi = max;
 		re->re_stride = 1;
 		goto out;
 	}

 	if (cfs_str2num_check(src->ls_str, src->ls_len,
 			      &re->re_lo, min, max)) {
 		/* <number> is parsed */
 		re->re_hi = re->re_lo;
 		re->re_stride = 1;
 		goto out;
 	}

 	if (!bracketed || !cfs_gettok(src, '-', &tok))
 		goto failed;

 	if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 			       &re->re_lo, min, max))
 		goto failed;

 	/* <number> - */
 	if (cfs_str2num_check(src->ls_str, src->ls_len,
 			      &re->re_hi, min, max)) {
 		/* <number> - <number> is parsed */
 		re->re_stride = 1;
 		goto out;
 	}

 	/* go to check <number> '-' <number> '/' <number> */
 	if (cfs_gettok(src, '/', &tok)) {
 		if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
 				       &re->re_hi, min, max))
 			goto failed;

 		/* <number> - <number> / ... */
 		if (cfs_str2num_check(src->ls_str, src->ls_len,
 				      &re->re_stride, min, max)) {
 			/* <number> - <number> / <number> is parsed */
 			goto out;
 		}
 	}

  out:
 	*expr = re;
 	return 0;

  failed:
 	LIBCFS_FREE(re, sizeof(*re));
 	return -EINVAL;
 }

 /**
  * Print the range expression \a re into specified \a buffer.
  * If \a bracketed is true, expression does not need additional
  * brackets.
  *
  * \retval number of characters written
  */
 static int
 cfs_range_expr_print(char *buffer, int count, struct cfs_range_expr *expr,
 		     bool bracketed)
 {
 	int i;
 	char s[] = "[";
 	char e[] = "]";

 	if (bracketed) {
 		s[0] = '\0';
 		e[0] = '\0';
 	}

 	if (expr->re_lo == expr->re_hi)
 		i = scnprintf(buffer, count, "%u", expr->re_lo);
 	else if (expr->re_stride == 1)
 		i = scnprintf(buffer, count, "%s%u-%u%s",
 			      s, expr->re_lo, expr->re_hi, e);
 	else
 		i = scnprintf(buffer, count, "%s%u-%u/%u%s",
 			      s, expr->re_lo, expr->re_hi, expr->re_stride, e);
 	return i;
 }

 /**
  * Print a list of range expressions (\a expr_list) into specified \a buffer.
  * If the list contains several expressions, separate them with comma
  * and surround the list with brackets.
  *
  * \retval number of characters written
  */
 int
 cfs_expr_list_print(char *buffer, int count, struct cfs_expr_list *expr_list)
 {
 	struct cfs_range_expr *expr;
 	int i = 0, j = 0;
 	int numexprs = 0;

 	if (count <= 0)
 		return 0;

 	list_for_each_entry(expr, &expr_list->el_exprs, re_link)
 		numexprs++;

 	if (numexprs > 1)
 		i += scnprintf(buffer + i, count - i, "[");

 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 		if (j++)
 			i += scnprintf(buffer + i, count - i, ",");
 		i += cfs_range_expr_print(buffer + i, count - i, expr,
 					  numexprs > 1);
 	}

 	if (numexprs > 1)
 		i += scnprintf(buffer + i, count - i, "]");

 	return i;
 }
 EXPORT_SYMBOL(cfs_expr_list_print);

 /**
  * Matches value (\a value) against ranges expression list \a expr_list.
  *
  * \retval 1 if \a value matches
  * \retval 0 otherwise
  */
 int
 cfs_expr_list_match(u32 value, struct cfs_expr_list *expr_list)
 {
 	struct cfs_range_expr *expr;

 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 		if (value >= expr->re_lo && value <= expr->re_hi &&
 		    !((value - expr->re_lo) % expr->re_stride))
 			return 1;
 	}

 	return 0;
 }
 EXPORT_SYMBOL(cfs_expr_list_match);

 /**
  * Convert express list (\a expr_list) to an array of all matched values
  *
  * \retval N N is total number of all matched values
  * \retval 0 if expression list is empty
  * \retval < 0 for failure
  */
 int
 cfs_expr_list_values(struct cfs_expr_list *expr_list, int max, u32 **valpp)
 {
 	struct cfs_range_expr *expr;
 	u32 *val;
 	int count = 0;
 	int i;

 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 		for (i = expr->re_lo; i <= expr->re_hi; i++) {
 			if (!((i - expr->re_lo) % expr->re_stride))
 				count++;
 		}
 	}

 	if (!count) /* empty expression list */
 		return 0;

 	if (count > max) {
 		CERROR("Number of values %d exceeds max allowed %d\n",
 		       max, count);
 		return -EINVAL;
 	}

 	LIBCFS_ALLOC(val, sizeof(val[0]) * count);
 	if (!val)
 		return -ENOMEM;

 	count = 0;
 	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
 		for (i = expr->re_lo; i <= expr->re_hi; i++) {
 			if (!((i - expr->re_lo) % expr->re_stride))
 				val[count++] = i;
 		}
 	}

 	*valpp = val;
 	return count;
 }
 EXPORT_SYMBOL(cfs_expr_list_values);

 /**
  * Frees cfs_range_expr structures of \a expr_list.
  *
  * \retval none
  */
 void
 cfs_expr_list_free(struct cfs_expr_list *expr_list)
 {
 	while (!list_empty(&expr_list->el_exprs)) {
 		struct cfs_range_expr *expr;

 		expr = list_entry(expr_list->el_exprs.next,
 				  struct cfs_range_expr, re_link);
 		list_del(&expr->re_link);
 		LIBCFS_FREE(expr, sizeof(*expr));
 	}

 	LIBCFS_FREE(expr_list, sizeof(*expr_list));
 }
 EXPORT_SYMBOL(cfs_expr_list_free);

 /**
  * Parses \<cfs_expr_list\> token of the syntax.
  *
  * \retval 0 if \a str parses to \<number\> | \<expr_list\>
  * \retval -errno otherwise
  */
 int
 cfs_expr_list_parse(char *str, int len, unsigned int min, unsigned int max,
 		    struct cfs_expr_list **elpp)
 {
 	struct cfs_expr_list *expr_list;
 	struct cfs_range_expr *expr;
 	struct cfs_lstr	src;
 	int rc;

 	LIBCFS_ALLOC(expr_list, sizeof(*expr_list));
 	if (!expr_list)
 		return -ENOMEM;

 	src.ls_str = str;
 	src.ls_len = len;

 	INIT_LIST_HEAD(&expr_list->el_exprs);

 	if (src.ls_str[0] == '[' &&
 	    src.ls_str[src.ls_len - 1] == ']') {
 		src.ls_str++;
 		src.ls_len -= 2;

 		rc = -EINVAL;
 		while (src.ls_str) {
 			struct cfs_lstr tok;

 			if (!cfs_gettok(&src, ',', &tok)) {
 				rc = -EINVAL;
 				break;
 			}

 			rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
 			if (rc)
 				break;

 			list_add_tail(&expr->re_link, &expr_list->el_exprs);
 		}
 	} else {
 		rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
 		if (!rc)
 			list_add_tail(&expr->re_link, &expr_list->el_exprs);
 	}

 	if (rc)
 		cfs_expr_list_free(expr_list);
 	else
 		*elpp = expr_list;

 	return rc;
 }
 EXPORT_SYMBOL(cfs_expr_list_parse);

 /**
  * Frees cfs_expr_list structures of \a list.
  *
  * For each struct cfs_expr_list structure found on \a list it frees
  * range_expr list attached to it and frees the cfs_expr_list itself.
  *
  * \retval none
  */
 void
 cfs_expr_list_free_list(struct list_head *list)
 {
 	struct cfs_expr_list *el;

 	while (!list_empty(list)) {
 		el = list_entry(list->next, struct cfs_expr_list, el_link);
 		list_del(&el->el_link);
 		cfs_expr_list_free(el);
 	}
 }
 EXPORT_SYMBOL(cfs_expr_list_free_list);
	/*
	* GPL HEADER START
	*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 only,
	* as published by the Free Software Foundation.
	*
	* 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 version 2 for more details (a copy is included
	* in the LICENSE file that accompanied this code).
	*
	* You should have received a copy of the GNU General Public License
	* version 2 along with this program; If not, see
	* http://www.gnu.org/licenses/gpl-2.0.html
	*
	* GPL HEADER END
	*/
	/*
	* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
	* Use is subject to license terms.
	*
	* Copyright (c) 2012, 2015 Intel Corporation.
	*/
	/*
	* This file is part of Lustre, http://www.lustre.org/
	* Lustre is a trademark of Sun Microsystems, Inc.
	*
	* String manipulation functions.
	*
	* libcfs/libcfs/libcfs_string.c
	*
	* Author: Nathan Rutman <nathan.rutman@sun.com>
	*/

	#include <linux/libcfs/libcfs.h>

	/* Convert a text string to a bitmask */
	int cfs_str2mask(const char str, const char (*bit2str)(int bit),
	int *oldmask, int minmask, int allmask)
	{
	const char *debugstr;
	char op = '\0';
	int newmask = minmask, i, len, found = 0;

	/* <str> must be a list of tokens separated by whitespace
	* and optionally an operator ('+' or '-'). If an operator
	* appears first in <str>, '*oldmask' is used as the starting point
	* (relative), otherwise minmask is used (absolute). An operator
	* applies to all following tokens up to the next operator.
	*/
	while (*str != '\0') {
	while (isspace(*str))
	str++;
	if (*str == '\0')
	break;
	if (str == '+' \|\| str == '-') {
	op = *str++;
	if (!found)
	/* only if first token is relative */
	newmask = *oldmask;
	while (isspace(*str))
	str++;
	if (str == '\0') / trailing op */
	return -EINVAL;
	}

	/* find token length */
	len = 0;
	while (str[len] != '\0' && !isspace(str[len]) &&
	str[len] != '+' && str[len] != '-')
	len++;

	/* match token */
	found = 0;
	for (i = 0; i < 32; i++) {
	debugstr = bit2str(i);
	if (debugstr && strlen(debugstr) == len &&
	!strncasecmp(str, debugstr, len)) {
	if (op == '-')
	newmask &= ~(1 << i);
	else
	newmask \|= (1 << i);
	found = 1;
	break;
	}
	}
	if (!found && len == 3 &&
	!strncasecmp(str, "ALL", len)) {
	if (op == '-')
	newmask = minmask;
	else
	newmask = allmask;
	found = 1;
	}
	if (!found) {
	CWARN("unknown mask '%.*s'.\n"
	"mask usage: [+\|-]<all\|type> ...\n", len, str);
	return -EINVAL;
	}
	str += len;
	}

	*oldmask = newmask;
	return 0;
	}

	/* get the first string out of @str */
	char cfs_firststr(char str, size_t size)
	{
	size_t i = 0;
	char *end;

	/* trim leading spaces */
	while (i < size && str && isspace(str)) {
	++i;
	++str;
	}

	/* string with all spaces */
	if (*str == '\0')
	goto out;

	end = str;
	while (i < size && end != '\0' && !isspace(end)) {
	++i;
	++end;
	}

	*end = '\0';
	out:
	return str;
	}
	EXPORT_SYMBOL(cfs_firststr);

	char *
	cfs_trimwhite(char *str)
	{
	char *end;

	while (isspace(*str))
	str++;

	end = str + strlen(str);
	while (end > str) {
	if (!isspace(end[-1]))
	break;
	end--;
	}

	*end = 0;
	return str;
	}
	EXPORT_SYMBOL(cfs_trimwhite);

	/**
	* Extracts tokens from strings.
	*
	* Looks for \a delim in string \a next, sets \a res to point to
	* substring before the delimiter, sets \a next right after the found
	* delimiter.
	*
	* \retval 1 if \a res points to a string of non-whitespace characters
	* \retval 0 otherwise
	*/
	int
	cfs_gettok(struct cfs_lstr next, char delim, struct cfs_lstr res)
	{
	char *end;

	if (!next->ls_str)
	return 0;

	/* skip leading white spaces */
	while (next->ls_len) {
	if (!isspace(*next->ls_str))
	break;
	next->ls_str++;
	next->ls_len--;
	}

	if (!next->ls_len) /* whitespaces only */
	return 0;

	if (*next->ls_str == delim) {
	/* first non-writespace is the delimiter */
	return 0;
	}

	res->ls_str = next->ls_str;
	end = memchr(next->ls_str, delim, next->ls_len);
	if (!end) {
	/* there is no the delimeter in the string */
	end = next->ls_str + next->ls_len;
	next->ls_str = NULL;
	} else {
	next->ls_str = end + 1;
	next->ls_len -= (end - res->ls_str + 1);
	}

	/* skip ending whitespaces */
	while (--end != res->ls_str) {
	if (!isspace(*end))
	break;
	}

	res->ls_len = end - res->ls_str + 1;
	return 1;
	}
	EXPORT_SYMBOL(cfs_gettok);

	/**
	* Converts string to integer.
	*
	* Accepts decimal and hexadecimal number recordings.
	*
	* \retval 1 if first \a nob chars of \a str convert to decimal or
	* hexadecimal integer in the range [\a min, \a max]
	* \retval 0 otherwise
	*/
	int
	cfs_str2num_check(char str, int nob, unsigned int num,
	unsigned int min, unsigned int max)
	{
	bool all_numbers = true;
	char *endp, cache;
	int rc;

	/**
	* kstrouint can only handle strings composed
	* of only numbers. We need to scan the string
	* passed in for the first non-digit character
	* and end the string at that location. If we
	* don't find any non-digit character we still
	* need to place a '\0' at position nob since
	* we are not interested in the rest of the
	* string which is longer than nob in size.
	* After we are done the character at the
	* position we placed '\0' must be restored.
	*/
	for (endp = str; endp < str + nob; endp++) {
	if (!isdigit(*endp)) {
	all_numbers = false;
	break;
	}
	}
	cache = *endp;
	*endp = '\0';

	rc = kstrtouint(str, 10, num);
	*endp = cache;
	if (rc \|\| !all_numbers)
	return 0;

	return (num >= min && num <= max);
	}
	EXPORT_SYMBOL(cfs_str2num_check);

	/**
	* Parses \<range_expr\> token of the syntax. If \a bracketed is false,
	* \a src should only have a single token which can be \<number\> or \*
	*
	* \retval pointer to allocated range_expr and initialized
	* range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
	`* src parses to
	* \<number\> \|
	* \<number\> '-' \<number\> \|
	* \<number\> '-' \<number\> '/' \<number\>
	* \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
	* -ENOMEM will be returned.
	*/
	static int
	cfs_range_expr_parse(struct cfs_lstr *src, unsigned int min, unsigned int max,
	int bracketed, struct cfs_range_expr **expr)
	{
	struct cfs_range_expr *re;
	struct cfs_lstr tok;

	LIBCFS_ALLOC(re, sizeof(*re));
	if (!re)
	return -ENOMEM;

	if (src->ls_len == 1 && src->ls_str[0] == '*') {
	re->re_lo = min;
	re->re_hi = max;
	re->re_stride = 1;
	goto out;
	}

	if (cfs_str2num_check(src->ls_str, src->ls_len,
	&re->re_lo, min, max)) {
	/* <number> is parsed */
	re->re_hi = re->re_lo;
	re->re_stride = 1;
	goto out;
	}

	if (!bracketed \|\| !cfs_gettok(src, '-', &tok))
	goto failed;

	if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
	&re->re_lo, min, max))
	goto failed;

	/* <number> - */
	if (cfs_str2num_check(src->ls_str, src->ls_len,
	&re->re_hi, min, max)) {
	/* <number> - <number> is parsed */
	re->re_stride = 1;
	goto out;
	}

	/* go to check <number> '-' <number> '/' <number> */
	if (cfs_gettok(src, '/', &tok)) {
	if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
	&re->re_hi, min, max))
	goto failed;

	/* <number> - <number> / ... */
	if (cfs_str2num_check(src->ls_str, src->ls_len,
	&re->re_stride, min, max)) {
	/* <number> - <number> / <number> is parsed */
	goto out;
	}
	}

	out:
	*expr = re;
	return 0;

	failed:
	LIBCFS_FREE(re, sizeof(*re));
	return -EINVAL;
	}

	/**
	* Print the range expression \a re into specified \a buffer.
	* If \a bracketed is true, expression does not need additional
	* brackets.
	*
	* \retval number of characters written
	*/
	static int
	cfs_range_expr_print(char buffer, int count, struct cfs_range_expr expr,
	bool bracketed)
	{
	int i;
	char s[] = "[";
	char e[] = "]";

	if (bracketed) {
	s[0] = '\0';
	e[0] = '\0';
	}

	if (expr->re_lo == expr->re_hi)
	i = scnprintf(buffer, count, "%u", expr->re_lo);
	else if (expr->re_stride == 1)
	i = scnprintf(buffer, count, "%s%u-%u%s",
	s, expr->re_lo, expr->re_hi, e);
	else
	i = scnprintf(buffer, count, "%s%u-%u/%u%s",
	s, expr->re_lo, expr->re_hi, expr->re_stride, e);
	return i;
	}

	/**
	* Print a list of range expressions (\a expr_list) into specified \a buffer.
	* If the list contains several expressions, separate them with comma
	* and surround the list with brackets.
	*
	* \retval number of characters written
	*/
	int
	cfs_expr_list_print(char buffer, int count, struct cfs_expr_list expr_list)
	{
	struct cfs_range_expr *expr;
	int i = 0, j = 0;
	int numexprs = 0;

	if (count <= 0)
	return 0;

	list_for_each_entry(expr, &expr_list->el_exprs, re_link)
	numexprs++;

	if (numexprs > 1)
	i += scnprintf(buffer + i, count - i, "[");

	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
	if (j++)
	i += scnprintf(buffer + i, count - i, ",");
	i += cfs_range_expr_print(buffer + i, count - i, expr,
	numexprs > 1);
	}

	if (numexprs > 1)
	i += scnprintf(buffer + i, count - i, "]");

	return i;
	}
	EXPORT_SYMBOL(cfs_expr_list_print);

	/**
	* Matches value (\a value) against ranges expression list \a expr_list.
	*
	* \retval 1 if \a value matches
	* \retval 0 otherwise
	*/
	int
	cfs_expr_list_match(u32 value, struct cfs_expr_list *expr_list)
	{
	struct cfs_range_expr *expr;

	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
	if (value >= expr->re_lo && value <= expr->re_hi &&
	!((value - expr->re_lo) % expr->re_stride))
	return 1;
	}

	return 0;
	}
	EXPORT_SYMBOL(cfs_expr_list_match);

	/**
	* Convert express list (\a expr_list) to an array of all matched values
	*
	* \retval N N is total number of all matched values
	* \retval 0 if expression list is empty
	* \retval < 0 for failure
	*/
	int
	cfs_expr_list_values(struct cfs_expr_list expr_list, int max, u32 *valpp)
	{
	struct cfs_range_expr *expr;
	u32 *val;
	int count = 0;
	int i;

	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
	for (i = expr->re_lo; i <= expr->re_hi; i++) {
	if (!((i - expr->re_lo) % expr->re_stride))
	count++;
	}
	}

	if (!count) /* empty expression list */
	return 0;

	if (count > max) {
	CERROR("Number of values %d exceeds max allowed %d\n",
	max, count);
	return -EINVAL;
	}

	LIBCFS_ALLOC(val, sizeof(val[0]) * count);
	if (!val)
	return -ENOMEM;

	count = 0;
	list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
	for (i = expr->re_lo; i <= expr->re_hi; i++) {
	if (!((i - expr->re_lo) % expr->re_stride))
	val[count++] = i;
	}
	}

	*valpp = val;
	return count;
	}
	EXPORT_SYMBOL(cfs_expr_list_values);

	/**
	* Frees cfs_range_expr structures of \a expr_list.
	*
	* \retval none
	*/
	void
	cfs_expr_list_free(struct cfs_expr_list *expr_list)
	{
	while (!list_empty(&expr_list->el_exprs)) {
	struct cfs_range_expr *expr;

	expr = list_entry(expr_list->el_exprs.next,
	struct cfs_range_expr, re_link);
	list_del(&expr->re_link);
	LIBCFS_FREE(expr, sizeof(*expr));
	}

	LIBCFS_FREE(expr_list, sizeof(*expr_list));
	}
	EXPORT_SYMBOL(cfs_expr_list_free);

	/**
	* Parses \<cfs_expr_list\> token of the syntax.
	*
	* \retval 0 if \a str parses to \<number\> \| \<expr_list\>
	* \retval -errno otherwise
	*/
	int
	cfs_expr_list_parse(char *str, int len, unsigned int min, unsigned int max,
	struct cfs_expr_list **elpp)
	{
	struct cfs_expr_list *expr_list;
	struct cfs_range_expr *expr;
	struct cfs_lstr src;
	int rc;

	LIBCFS_ALLOC(expr_list, sizeof(*expr_list));
	if (!expr_list)
	return -ENOMEM;

	src.ls_str = str;
	src.ls_len = len;

	INIT_LIST_HEAD(&expr_list->el_exprs);

	if (src.ls_str[0] == '[' &&
	src.ls_str[src.ls_len - 1] == ']') {
	src.ls_str++;
	src.ls_len -= 2;

	rc = -EINVAL;
	while (src.ls_str) {
	struct cfs_lstr tok;

	if (!cfs_gettok(&src, ',', &tok)) {
	rc = -EINVAL;
	break;
	}

	rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
	if (rc)
	break;

	list_add_tail(&expr->re_link, &expr_list->el_exprs);
	}
	} else {
	rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
	if (!rc)
	list_add_tail(&expr->re_link, &expr_list->el_exprs);
	}

	if (rc)
	cfs_expr_list_free(expr_list);
	else
	*elpp = expr_list;

	return rc;
	}
	EXPORT_SYMBOL(cfs_expr_list_parse);

	/**
	* Frees cfs_expr_list structures of \a list.
	*
	* For each struct cfs_expr_list structure found on \a list it frees
	* range_expr list attached to it and frees the cfs_expr_list itself.
	*
	* \retval none
	*/
	void
	cfs_expr_list_free_list(struct list_head *list)
	{
	struct cfs_expr_list *el;

	while (!list_empty(list)) {
	el = list_entry(list->next, struct cfs_expr_list, el_link);
	list_del(&el->el_link);
	cfs_expr_list_free(el);
	}
	}
	EXPORT_SYMBOL(cfs_expr_list_free_list);