[PATCH] Add parse_integer() (replacement for simple_strto*())

[PATCH] Add parse_integer() (replacement for simple_strto*())

[Alexey Dobriyan]

kstrto*() and kstrto*_from_user() family of functions were added
help with parsing one integer written as string to proc/sysfs/debugfs
files and pass it elsewhere. But they have a limitation: string passed
must end with \0 or \n\0. There are enough places where kstrto*()
functions can't be used because of this limitation. Trivial example:
parse "%u.%u".

Currently the only way to parse everything is simple_strto*() family of
functions. But they are suboptimal:
* they do not detect overflow,
* there are only 2(4) of them -- long and "long long" version.
  This leads to silent truncation in the most simple case:

	val = strtoul(s, NULL, 0);

* half of the people think that "char **endp" argument is necessary and
  add unnecessary variable.

OpenBSD people, fed up with how complex correct integer parsing is, added
strtonum(3) to fixup for deficiencies of libc-style integer parsing:
http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man3/strtonum.3?query=strtonum&arch=i386

It'd be OK to copy that but it relies on "errno" and fixed strings as
error-reporting channel which I think is not OK for kernel.
strtonum() also doesn't report number of characted consumed.

What to do?

Enter parse_integer().

	int parse_integer(const char *s, unsigned int base, T *val);

Rationale:

* parse_integer() is exactly 1 (one) interface not 2 or many,
  one for each type.
* parse_integer() reports -E errors reliably in a canonical kernel way:

	rv = parse_integer(str, 10, &val);
	if (rv < 0)
		return rv;

* parse_integer() writes result only if there were no errors, at least
  one digit was consumed.
* parse_integer doesn't mix error reporting channel and value channel,
  it does mix error and number-of-character-consumed channel, though.

* parse_integer() reports number of characters consumed, makes parsing
  multiple values easy:

	rv = parse_integer(str, 0, &val1);
	if (rv < 0)
		return rv;
	s += rv;
	if (s != '.')
		return -EINVAL;
	rv = parse_integer(str, 0, &val2);
	if (rv < 0)
		return rv;
	if (str[rv] != '\0')
		return -EINVAL;

There are several deficiencies in parse_integer() compared to strto*():
* can't be used in initializers:

	const T x = strtoul();

* can't be used with bitfields,
* can't be used in experessions:

	x = strtol() * 1024;
	x = y = strtol() * 1024;
	x += strtol();

In defense of parse_integer() all I can say, is that using strtol() in
expression or initializer promotes no error checking and thus probably
should not be encouraged in C, language with no built-in error checking
anyway.

The amount of "x = y = strtol()" expressions in kernel is very small.
The amount of direct usage in expression is not small, but can be
counted as an acceptable loss.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 include/linux/kernel.h |   72 +++++++++++++++++++
 lib/Makefile           |    1 
 lib/kstrtox.c          |   27 +------
 lib/parse-integer.c    |  180 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 257 insertions(+), 23 deletions(-)

--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -251,6 +251,78 @@ void do_exit(long error_code)
 void complete_and_exit(struct completion *, long)
 	__noreturn;
 
+/*
+ * int parse_integer(const char *s, unsigned int base, T *val);
+ *
+ * Convert integer string representation to an integer.
+ * If an integer doesn't fit into specified type, -E is returned.
+ *
+ * Conversion to signed integer accepts sign "-".
+ * Conversion to an unsigned integer doesn't accept sign "-".
+ *
+ * Radix 0 means autodetection: leading "0x" implies radix 16,
+ * leading "0" implies radix 8, otherwise radix is 10.
+ * Autodetection hints work after optional sign, but not before.
+ *
+ * If -E is returned, result is not touched.
+ *
+ * "T = char" case is not supported because -f{un,}signed-char can silently
+ * change range of accepted values.
+ */
+#define parse_integer(s, base, val)	\
+({					\
+	const char *_s = (s);		\
+	unsigned int _base = (base);	\
+	typeof(val) _val = (val);	\
+					\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), signed char *),	\
+	_parse_integer_sc(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned char *),	\
+	_parse_integer_uc(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), short *),		\
+	_parse_integer_s(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned short *),	\
+	_parse_integer_us(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), int *),		\
+	_parse_integer_i(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned int *),	\
+	_parse_integer_u(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long *) && BITS_PER_LONG == 32,\
+	_parse_integer_i(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long *) && BITS_PER_LONG == 64,\
+	_parse_integer_ll(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long *) && BITS_PER_LONG == 32,\
+	_parse_integer_u(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long *) && BITS_PER_LONG == 64,\
+	_parse_integer_ull(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long long *),	\
+	_parse_integer_ll(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long long *),\
+	_parse_integer_ull(_s, _base, (void *)_val),			\
+	_parse_integer_link_time_error()))))))))))));	\
+})
+int _parse_integer_sc(const char *s, unsigned int base, signed char *val);
+int _parse_integer_uc(const char *s, unsigned int base, unsigned char *val);
+int _parse_integer_s(const char *s, unsigned int base, short *val);
+int _parse_integer_us(const char *s, unsigned int base, unsigned short *val);
+int _parse_integer_i(const char *s, unsigned int base, int *val);
+int _parse_integer_u(const char *s, unsigned int base, unsigned int *val);
+int _parse_integer_ll(const char *s, unsigned int base, long long *val);
+int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val);
+void _parse_integer_link_time_error(void);
+
 /* Internal, do not use. */
 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
 obj-y += hexdump.o
 obj-$(CONFIG_TEST_HEXDUMP) += test-hexdump.o
 obj-y += kstrtox.o
+obj-y += parse-integer.o
 obj-$(CONFIG_TEST_BPF) += test_bpf.o
 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
 obj-$(CONFIG_TEST_KASAN) += test_kasan.o
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -20,22 +20,6 @@
 #include <asm/uaccess.h>
 #include "kstrtox.h"
 
-const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
-{
-	if (*base == 0) {
-		if (s[0] == '0') {
-			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
-				*base = 16;
-			else
-				*base = 8;
-		} else
-			*base = 10;
-	}
-	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
-		s += 2;
-	return s;
-}
-
 /*
  * Convert non-negative integer string representation in explicitly given radix
  * to an integer.
@@ -86,14 +70,11 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
 static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 {
 	unsigned long long _res;
-	unsigned int rv;
+	int rv;
 
-	s = _parse_integer_fixup_radix(s, &base);
-	rv = _parse_integer(s, base, &_res);
-	if (rv & KSTRTOX_OVERFLOW)
-		return -ERANGE;
-	if (rv == 0)
-		return -EINVAL;
+	rv = parse_integer(s, base, &_res);
+	if (rv < 0)
+		return rv;
 	s += rv;
 	if (*s == '\n')
 		s++;
--- /dev/null
+++ b/lib/parse-integer.c
@@ -0,0 +1,180 @@
+/*
+ * See parse_integer().
+ *
+ * Individual dispatch functions in this file aren't supposed to be used
+ * directly and thus aren't advertised and documented despited being exported.
+ *
+ * Do not use any function in this file for any reason.
+ */
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <asm/bug.h>
+#include "kstrtox.h"
+
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
+{
+	if (*base == 0) {
+		if (s[0] == '0') {
+			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
+				*base = 16;
+			else
+				*base = 8;
+		} else
+			*base = 10;
+	}
+	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
+		s += 2;
+	BUG_ON(*base < 2 || *base > 16);
+	return s;
+}
+
+int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val)
+{
+	const char *s0 = s, *sd;
+	unsigned long long acc;
+
+	s = sd = _parse_integer_fixup_radix(s0, &base);
+	acc = 0;
+	while (*s != '\0') {
+		unsigned int d;
+
+		if ('0' <= *s && *s <= '9')
+			d = *s - '0';
+		else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
+			d = _tolower(*s) - 'a' + 10;
+		else
+			break;
+		if (d >= base)
+			break;
+		/* Overflow can't happen early enough. */
+		if ((acc >> 60) && acc > div_u64(ULLONG_MAX - d, base))
+			return -ERANGE;
+		acc = acc * base + d;
+		s++;
+	}
+	/* At least one digit has to be converted. */
+	if (s == sd)
+		return -EINVAL;
+	*val = acc;
+	/* Radix 1 is not supported otherwise returned length can overflow. */
+	return s - s0;
+}
+EXPORT_SYMBOL(_parse_integer_ull);
+
+int _parse_integer_ll(const char *s, unsigned int base, long long *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	if (*s == '-') {
+		rv = _parse_integer_ull(s + 1, base, &tmp);
+		if (rv < 0)
+			return rv;
+		if ((long long)-tmp >= 0)
+			return -ERANGE;
+		*val = -tmp;
+		return rv + 1;
+	} else {
+		rv = _parse_integer_ull(s, base, &tmp);
+		if (rv < 0)
+			return rv;
+		if ((long long)tmp < 0)
+			return -ERANGE;
+		*val = tmp;
+		return rv;
+	}
+}
+EXPORT_SYMBOL(_parse_integer_ll);
+
+int _parse_integer_u(const char *s, unsigned int base, unsigned int *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned int)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_u);
+
+int _parse_integer_i(const char *s, unsigned int base, int *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (int)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_i);
+
+int _parse_integer_us(const char *s, unsigned int base, unsigned short *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned short)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_us);
+
+int _parse_integer_s(const char *s, unsigned int base, short *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (short)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_s);
+
+int _parse_integer_uc(const char *s, unsigned int base, unsigned char *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned char)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_uc);
+
+int _parse_integer_sc(const char *s, unsigned int base, signed char *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (signed char)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_sc);

Re: [PATCH] Add parse_integer() (replacement for simple_strto*())

[Alexey Dobriyan]

On Thu, Apr 09, 2015 at 06:26:14PM +0300, Alexey Dobriyan wrote:
> 	int parse_integer(const char *s, unsigned int base, T *val);

This is an example how conversion looks like (for mm/ directory):


--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4187,20 +4187,23 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
 	struct fd efile;
 	struct fd cfile;
 	const char *name;
-	char *endp;
 	int ret;
 
 	buf = strstrip(buf);
 
-	efd = simple_strtoul(buf, &endp, 10);
-	if (*endp != ' ')
+	ret = parse_integer(buf, 10, &efd);
+	if (ret < 0)
+		return ret;
+	if (buf[ret] != ' ')
 		return -EINVAL;
-	buf = endp + 1;
+	buf += ret + 1;
 
-	cfd = simple_strtoul(buf, &endp, 10);
-	if ((*endp != ' ') && (*endp != '\0'))
+	ret = parse_integer(buf, 10, &cfd);
+	if (ret < 0)
+		return ret;
+	if (buf[ret] != ' ' && buf[ret] != '\0')
 		return -EINVAL;
-	buf = endp + 1;
+	buf += ret + 1;
 
 	event = kzalloc(sizeof(*event), GFP_KERNEL);
 	if (!event)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5977,7 +5977,7 @@ static int __init set_hashdist(char *str)
 {
 	if (!str)
 		return 0;
-	hashdist = simple_strtoul(str, &str, 0);
+	parse_integer(str, 0, &hashdist);
 	return 1;
 }
 __setup("hashdist=", set_hashdist);
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2742,6 +2742,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
 	struct mempolicy *mpol = NULL;
 	uid_t uid;
 	gid_t gid;
+	int rv;
 
 	while (options != NULL) {
 		this_char = options;
@@ -2795,14 +2796,15 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
 		} else if (!strcmp(this_char,"mode")) {
 			if (remount)
 				continue;
-			sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
-			if (*rest)
+			rv = parse_integer(value, 8, &sbinfo->mode);
+			if (rv < 0 || value[rv])
 				goto bad_val;
+			sbinfo->mode &= 07777;
 		} else if (!strcmp(this_char,"uid")) {
 			if (remount)
 				continue;
-			uid = simple_strtoul(value, &rest, 0);
-			if (*rest)
+			rv = parse_integer(value, 0, &uid);
+			if (rv < 0 || value[rv])
 				goto bad_val;
 			sbinfo->uid = make_kuid(current_user_ns(), uid);
 			if (!uid_valid(sbinfo->uid))
@@ -2810,8 +2812,8 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
 		} else if (!strcmp(this_char,"gid")) {
 			if (remount)
 				continue;
-			gid = simple_strtoul(value, &rest, 0);
-			if (*rest)
+			rv = parse_integer(value, 0, &gid);
+			if (rv < 0 || value[rv])
 				goto bad_val;
 			sbinfo->gid = make_kgid(current_user_ns(), gid);
 			if (!gid_valid(sbinfo->gid))

Re: [PATCH] Add parse_integer() (replacement for simple_strto*())

[Andrew Morton]

On Thu, 9 Apr 2015 18:26:14 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:

> kstrto*() and kstrto*_from_user() family of functions were added
> help with parsing one integer written as string to proc/sysfs/debugfs
> files and pass it elsewhere. But they have a limitation: string passed
> must end with \0 or \n\0. There are enough places where kstrto*()
> functions can't be used because of this limitation. Trivial example:
> parse "%u.%u".
> 
> ...
>
>  include/linux/kernel.h |   72 +++++++++++++++++++
>  lib/Makefile           |    1 
>  lib/kstrtox.c          |   27 +------
>  lib/parse-integer.c    |  180 +++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 257 insertions(+), 23 deletions(-)

That's a lot of code for something which is almost the same as
kstrtofoo().

Can we hack up _kstrtoull() to optionally provide the new behaviour?
We could use the top bit of `base' to select the behaviour.  Something
like

--- a/lib/kstrtox.c~a
+++ a/lib/kstrtox.c
@@ -87,19 +87,23 @@ static int _kstrtoull(const char *s, uns
 {
 	unsigned long long _res;
 	unsigned int rv;
+	const char *cursor;
+	const unsigned int __base = base & 0x7fffffff;
 
-	s = _parse_integer_fixup_radix(s, &base);
-	rv = _parse_integer(s, base, &_res);
+	cursor = _parse_integer_fixup_radix(s, &__base);
+	rv = _parse_integer(cursor, __base, &_res);
 	if (rv & KSTRTOX_OVERFLOW)
 		return -ERANGE;
 	if (rv == 0)
 		return -EINVAL;
-	s += rv;
-	if (*s == '\n')
-		s++;
-	if (*s)
-		return -EINVAL;
+	cursor += rv;
 	*res = _res;
+	if (base & 0x80000000)
+		return cursor - s;
+	if (*cursor == '\n')
+		cursor++;
+	if (*cursor)
+		return -EINVAL;
 	return 0;
 }
 
then add a bunch of wrappers?

Re: [PATCH] Add parse_integer() (replacement for simple_strto*())

[Alexey Dobriyan]

On Thu, Apr 09, 2015 at 01:02:47PM -0700, Andrew Morton wrote:
> On Thu, 9 Apr 2015 18:26:14 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> 
> > kstrto*() and kstrto*_from_user() family of functions were added
> > help with parsing one integer written as string to proc/sysfs/debugfs
> > files and pass it elsewhere. But they have a limitation: string passed
> > must end with \0 or \n\0. There are enough places where kstrto*()
> > functions can't be used because of this limitation. Trivial example:
> > parse "%u.%u".
> > 
> > ...
> >
> >  include/linux/kernel.h |   72 +++++++++++++++++++
> >  lib/Makefile           |    1 
> >  lib/kstrtox.c          |   27 +------
> >  lib/parse-integer.c    |  180 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 257 insertions(+), 23 deletions(-)
> 
> That's a lot of code for something which is almost the same as
> kstrtofoo().
> 
> Can we hack up _kstrtoull() to optionally provide the new behaviour?
> We could use the top bit of `base' to select the behaviour.

Hmm, OK. I did it the opposite way, though.
parse_integer() becomes core interface, kstrto*() become wrappers.

	Alexey

[PATCH 1/2] Add parse_integer() (replacement for simple_strto*())

[Alexey Dobriyan]

kstrto*() and kstrto*_from_user() family of functions were added
help with parsing one integer written as string to proc/sysfs/debugfs
files and pass it elsewhere. But they have a limitation: string passed
must end with \0 or \n\0. There are enough places where kstrto*()
functions can't be used because of this limitation. Trivial example:
parse "%u.%u".

Currently the only way to parse everything is simple_strto*() family of
functions. But they are suboptimal:
* they do not detect overflow,
* there are only 2(4) of them -- long and "long long" version.
  This leads to silent truncation in the most simple case:

	val = strtoul(s, NULL, 0);

* half of the people think that "char **endp" argument is necessary and
  add unnecessary variable.

OpenBSD people, fed up with how complex correct integer parsing is, added
strtonum(3) to fixup for deficiencies of libc-style integer parsing:
http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man3/strtonum.3?query=strtonum&arch=i386

It'd be OK to copy that but it relies on "errno" and fixed strings as
error-reporting channel which I think is not OK for kernel.
strtonum() also doesn't report number of characted consumed.

What to do?

Enter parse_integer().

	int parse_integer(const char *s, unsigned int base, T *val);

Rationale:

* parse_integer() is exactly 1 (one) interface not 2 or many,
  one for each type.
* parse_integer() reports -E errors reliably in a canonical kernel way:

	rv = parse_integer(str, 10, &val);
	if (rv < 0)
		return rv;

* parse_integer() writes result only if there were no errors, at least
  one digit was consumed.
* parse_integer doesn't mix error reporting channel and value channel,
  it does mix error and number-of-character-consumed channel, though.

* parse_integer() reports number of characters consumed, makes parsing
  multiple values easy:

	rv = parse_integer(str, 0, &val1);
	if (rv < 0)
		return rv;
	s += rv;
	if (s != '.')
		return -EINVAL;
	rv = parse_integer(str, 0, &val2);
	if (rv < 0)
		return rv;
	if (str[rv] != '\0')
		return -EINVAL;

There are several deficiencies in parse_integer() compared to strto*():
* can't be used in initializers:

	const T x = strtoul();

* can't be used with bitfields,
* can't be used in experessions:

	x = strtol() * 1024;
	x = y = strtol() * 1024;
	x += strtol();

In defense of parse_integer() all I can say, is that using strtol() in
expression or initializer promotes no error checking and thus probably
should not be encouraged in C, language with no built-in error checking
anyway.

The amount of "x = y = strtol()" expressions in kernel is very small.
The amount of direct usage in expression is not small, but can be
counted as an acceptable loss.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 include/linux/kernel.h        |    3 
 include/linux/parse-integer.h |   79 ++++++++++++++++
 lib/Makefile                  |    1 
 lib/kstrtox.c                 |   76 ++++-----------
 lib/kstrtox.h                 |    1 
 lib/parse-integer.c           |  203 ++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 307 insertions(+), 56 deletions(-)

--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -10,6 +10,7 @@
 #include <linux/bitops.h>
 #include <linux/log2.h>
 #include <linux/typecheck.h>
+#include <linux/parse-integer.h>
 #include <linux/printk.h>
 #include <linux/dynamic_debug.h>
 #include <asm/byteorder.h>
@@ -375,7 +376,7 @@ static inline int __must_check kstrtos32_from_user(const char __user *s, size_t
 	return kstrtoint_from_user(s, count, base, res);
 }
 
-/* Obsolete, do not use.  Use kstrto<foo> instead */
+/* Obsolete, do not use. Use parse_integer(), kstrto*() or kstrto*_from_user(). */
 
 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 extern long simple_strtol(const char *,char **,unsigned int);
--- /dev/null
+++ b/include/linux/parse-integer.h
@@ -0,0 +1,79 @@
+#ifndef _PARSE_INTEGER_H
+#define _PARSE_INTEGER_H
+#include <asm/bitsperlong.h>
+
+/*
+ * int parse_integer(const char *s, unsigned int base, T *val);
+ *
+ * Convert integer string representation to an integer.
+ * Range of accepted values equals to that of type T.
+ *
+ * Conversion to unsigned integer accepts sign "+".
+ * Conversion to signed integer accepts sign "+" and sign "-".
+ *
+ * Radix 0 means autodetection: leading "0x" implies radix 16,
+ * leading "0" implies radix 8, otherwise radix is 10.
+ * Autodetection hint works after optional sign, but not before.
+ *
+ * Return number of characters parsed or -E.
+ *
+ * "T = char" case is not supported because -f{un,}signed-char can silently
+ * change range of accepted values.
+ */
+#define parse_integer(s, base, val)	\
+({					\
+	const char *_s = (s);		\
+	unsigned int _base = (base);	\
+	typeof(val) _val = (val);	\
+					\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), signed char *),	\
+	_parse_integer_sc(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned char *),	\
+	_parse_integer_uc(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), short *),		\
+	_parse_integer_s(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned short *),	\
+	_parse_integer_us(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), int *),		\
+	_parse_integer_i(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned int *),	\
+	_parse_integer_u(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long *) && BITS_PER_LONG == 32,\
+	_parse_integer_i(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long *) && BITS_PER_LONG == 64,\
+	_parse_integer_ll(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long *) && BITS_PER_LONG == 32,\
+	_parse_integer_u(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long *) && BITS_PER_LONG == 64,\
+	_parse_integer_ull(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), long long *),	\
+	_parse_integer_ll(_s, _base, (void *)_val),			\
+	__builtin_choose_expr(						\
+	__builtin_types_compatible_p(typeof(_val), unsigned long long *),\
+	_parse_integer_ull(_s, _base, (void *)_val),			\
+	_parse_integer_link_time_error()))))))))))));	\
+})
+int _parse_integer_sc(const char *s, unsigned int base, signed char *val);
+int _parse_integer_uc(const char *s, unsigned int base, unsigned char *val);
+int _parse_integer_s(const char *s, unsigned int base, short *val);
+int _parse_integer_us(const char *s, unsigned int base, unsigned short *val);
+int _parse_integer_i(const char *s, unsigned int base, int *val);
+int _parse_integer_u(const char *s, unsigned int base, unsigned int *val);
+int _parse_integer_ll(const char *s, unsigned int base, long long *val);
+int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val);
+void _parse_integer_link_time_error(void);
+
+/* internal, do not use */
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
+#endif
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
 obj-y += hexdump.o
 obj-$(CONFIG_TEST_HEXDUMP) += test-hexdump.o
 obj-y += kstrtox.o
+obj-y += parse-integer.o
 obj-$(CONFIG_TEST_BPF) += test_bpf.o
 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
 obj-$(CONFIG_TEST_KASAN) += test_kasan.o
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -20,22 +20,6 @@
 #include <asm/uaccess.h>
 #include "kstrtox.h"
 
-const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
-{
-	if (*base == 0) {
-		if (s[0] == '0') {
-			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
-				*base = 16;
-			else
-				*base = 8;
-		} else
-			*base = 10;
-	}
-	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
-		s += 2;
-	return s;
-}
-
 /*
  * Convert non-negative integer string representation in explicitly given radix
  * to an integer.
@@ -83,26 +67,6 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
 	return rv;
 }
 
-static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
-{
-	unsigned long long _res;
-	unsigned int rv;
-
-	s = _parse_integer_fixup_radix(s, &base);
-	rv = _parse_integer(s, base, &_res);
-	if (rv & KSTRTOX_OVERFLOW)
-		return -ERANGE;
-	if (rv == 0)
-		return -EINVAL;
-	s += rv;
-	if (*s == '\n')
-		s++;
-	if (*s)
-		return -EINVAL;
-	*res = _res;
-	return 0;
-}
-
 /**
  * kstrtoull - convert a string to an unsigned long long
  * @s: The start of the string. The string must be null-terminated, and may also
@@ -121,9 +85,19 @@ static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
  */
 int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 {
-	if (s[0] == '+')
+	unsigned long long _res;
+	int rv;
+
+	rv = parse_integer(s, base, &_res);
+	if (rv < 0)
+		return rv;
+	s += rv;
+	if (*s == '\n')
 		s++;
-	return _kstrtoull(s, base, res);
+	if (*s)
+		return -EINVAL;
+	*res = _res;
+	return 0;
 }
 EXPORT_SYMBOL(kstrtoull);
 
@@ -145,24 +119,18 @@ EXPORT_SYMBOL(kstrtoull);
  */
 int kstrtoll(const char *s, unsigned int base, long long *res)
 {
-	unsigned long long tmp;
+	long long _res;
 	int rv;
 
-	if (s[0] == '-') {
-		rv = _kstrtoull(s + 1, base, &tmp);
-		if (rv < 0)
-			return rv;
-		if ((long long)(-tmp) >= 0)
-			return -ERANGE;
-		*res = -tmp;
-	} else {
-		rv = kstrtoull(s, base, &tmp);
-		if (rv < 0)
-			return rv;
-		if ((long long)tmp < 0)
-			return -ERANGE;
-		*res = tmp;
-	}
+	rv = parse_integer(s, base, &_res);
+	if (rv < 0)
+		return rv;
+	s += rv;
+	if (*s == '\n')
+		s++;
+	if (*s)
+		return -EINVAL;
+	*res = _res;
 	return 0;
 }
 EXPORT_SYMBOL(kstrtoll);
--- a/lib/kstrtox.h
+++ b/lib/kstrtox.h
@@ -2,7 +2,6 @@
 #define _LIB_KSTRTOX_H
 
 #define KSTRTOX_OVERFLOW	(1U << 31)
-const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
 unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res);
 
 #endif
--- /dev/null
+++ b/lib/parse-integer.c
@@ -0,0 +1,203 @@
+/*
+ * See parse_integer().
+ *
+ * Individual dispatch functions in this file aren't supposed to be used
+ * directly and thus aren't advertised and documented despited being exported.
+ *
+ * Do not use any function in this file for any reason.
+ */
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/parse-integer.h>
+#include <asm/bug.h>
+
+const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
+{
+	if (*base == 0) {
+		if (s[0] == '0') {
+			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))
+				*base = 16;
+			else
+				*base = 8;
+		} else
+			*base = 10;
+	}
+	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')
+		s += 2;
+	BUG_ON(*base < 2 || *base > 16);
+	return s;
+}
+
+static int __parse_integer(const char *s, unsigned int base, unsigned long long *val)
+{
+	const char *s0 = s, *sd;
+	unsigned long long acc;
+
+	s = sd = _parse_integer_fixup_radix(s0, &base);
+	acc = 0;
+	while (*s != '\0') {
+		unsigned int d;
+
+		if ('0' <= *s && *s <= '9')
+			d = *s - '0';
+		else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
+			d = _tolower(*s) - 'a' + 10;
+		else
+			break;
+		if (d >= base)
+			break;
+		/* Overflow can't happen early enough. */
+		if ((acc >> 60) && acc > div_u64(ULLONG_MAX - d, base))
+			return -ERANGE;
+		acc = acc * base + d;
+		s++;
+	}
+	/* At least one digit has to be converted. */
+	if (s == sd)
+		return -EINVAL;
+	*val = acc;
+	/* Radix 1 is not supported otherwise returned length can overflow. */
+	return s - s0;
+}
+
+int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val)
+{
+	int rv;
+
+	if (*s == '-') {
+		return -EINVAL;
+	} else if (*s == '+') {
+		rv = __parse_integer(s + 1, base, val);
+		if (rv < 0)
+			return rv;
+		return rv + 1;
+	} else
+		return __parse_integer(s, base, val);
+}
+EXPORT_SYMBOL(_parse_integer_ull);
+
+int _parse_integer_ll(const char *s, unsigned int base, long long *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	if (*s == '-') {
+		rv = __parse_integer(s + 1, base, &tmp);
+		if (rv < 0)
+			return rv;
+		if ((long long)-tmp >= 0)
+			return -ERANGE;
+		*val = -tmp;
+		return rv + 1;
+	} else if (*s == '+') {
+		rv = __parse_integer(s + 1, base, &tmp);
+		if (rv < 0)
+			return rv;
+		if ((long long)tmp < 0)
+			return -ERANGE;
+		*val = tmp;
+		return rv + 1;
+	} else {
+		rv = __parse_integer(s, base, &tmp);
+		if (rv < 0)
+			return rv;
+		if ((long long)tmp < 0)
+			return -ERANGE;
+		*val = tmp;
+		return rv;
+	}
+}
+EXPORT_SYMBOL(_parse_integer_ll);
+
+int _parse_integer_u(const char *s, unsigned int base, unsigned int *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned int)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_u);
+
+int _parse_integer_i(const char *s, unsigned int base, int *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (int)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_i);
+
+int _parse_integer_us(const char *s, unsigned int base, unsigned short *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned short)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_us);
+
+int _parse_integer_s(const char *s, unsigned int base, short *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (short)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_s);
+
+int _parse_integer_uc(const char *s, unsigned int base, unsigned char *val)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = _parse_integer_ull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned char)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_uc);
+
+int _parse_integer_sc(const char *s, unsigned int base, signed char *val)
+{
+	long long tmp;
+	int rv;
+
+	rv = _parse_integer_ll(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (signed char)tmp)
+		return -ERANGE;
+	*val = tmp;
+	return rv;
+}
+EXPORT_SYMBOL(_parse_integer_sc);
-- 
2.0.4

[PATCH 2/2] parse_integer: rewrite kstrto*()

[Alexey Dobriyan]

Rewrite kstrto*() functions through parse_integer().

_kstrtoul() and _kstrtol() are removed because parse_integer()
can dispatch based on BITS_PER_LONG saving function call.

Also move function definitions and comment one instance.
Remove redundant boilerplate comments from elsewhere.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 include/linux/kernel.h        |  124 -----------------------
 include/linux/parse-integer.h |  111 +++++++++++++++++++++
 lib/kstrtox.c                 |  222 ------------------------------------------
 lib/parse-integer.c           |   38 ++++++-
 4 files changed, 145 insertions(+), 350 deletions(-)

--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -252,130 +252,6 @@ void do_exit(long error_code)
 void complete_and_exit(struct completion *, long)
 	__noreturn;
 
-/* Internal, do not use. */
-int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
-int __must_check _kstrtol(const char *s, unsigned int base, long *res);
-
-int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
-int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
-
-/**
- * kstrtoul - convert a string to an unsigned long
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign, but not a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
-*/
-static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
-{
-	/*
-	 * We want to shortcut function call, but
-	 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
-	 */
-	if (sizeof(unsigned long) == sizeof(unsigned long long) &&
-	    __alignof__(unsigned long) == __alignof__(unsigned long long))
-		return kstrtoull(s, base, (unsigned long long *)res);
-	else
-		return _kstrtoul(s, base, res);
-}
-
-/**
- * kstrtol - convert a string to a long
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign or a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
- */
-static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
-{
-	/*
-	 * We want to shortcut function call, but
-	 * __builtin_types_compatible_p(long, long long) = 0.
-	 */
-	if (sizeof(long) == sizeof(long long) &&
-	    __alignof__(long) == __alignof__(long long))
-		return kstrtoll(s, base, (long long *)res);
-	else
-		return _kstrtol(s, base, res);
-}
-
-int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
-int __must_check kstrtoint(const char *s, unsigned int base, int *res);
-
-static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
-{
-	return kstrtoull(s, base, res);
-}
-
-static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
-{
-	return kstrtoll(s, base, res);
-}
-
-static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
-{
-	return kstrtouint(s, base, res);
-}
-
-static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
-{
-	return kstrtoint(s, base, res);
-}
-
-int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
-int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
-int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
-int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
-
-int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
-int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
-int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
-int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
-int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
-int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
-int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
-int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
-int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
-int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
-
-static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
-{
-	return kstrtoull_from_user(s, count, base, res);
-}
-
-static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
-{
-	return kstrtoll_from_user(s, count, base, res);
-}
-
-static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
-{
-	return kstrtouint_from_user(s, count, base, res);
-}
-
-static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
-{
-	return kstrtoint_from_user(s, count, base, res);
-}
-
 /* Obsolete, do not use. Use parse_integer(), kstrto*() or kstrto*_from_user(). */
 
 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
--- a/include/linux/parse-integer.h
+++ b/include/linux/parse-integer.h
@@ -75,5 +75,116 @@ int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val
 void _parse_integer_link_time_error(void);
 
 /* internal, do not use */
+#define PARSE_INTEGER_NEWLINE 0x80000000u
+
+/*
+ * Convert integer string representation terminated by \n\0 or \0 to an integer.
+ *
+ * Return 0 on success or -E.
+ *
+ * See parse_integer().
+ */
+static inline int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtoll(const char *s, unsigned int base, long long *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtoint(const char *s, unsigned int base, int *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
+{
+	return kstrtoull(s, base, res);
+}
+
+static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
+{
+	return kstrtoll(s, base, res);
+}
+
+static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
+{
+	return kstrtouint(s, base, res);
+}
+
+static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
+{
+	return kstrtoint(s, base, res);
+}
+
+static inline int __must_check kstrtou16(const char *s, unsigned int base, u16 *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtos16(const char *s, unsigned int base, s16 *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtou8(const char *s, unsigned int base, u8 *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+static inline int __must_check kstrtos8(const char *s, unsigned int base, s8 *res)
+{
+	return parse_integer(s, base | PARSE_INTEGER_NEWLINE, res);
+}
+
+int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
+int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
+int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
+int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
+int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
+int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
+int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
+int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
+int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
+int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
+
+static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
+{
+	return kstrtoull_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
+{
+	return kstrtoll_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
+{
+	return kstrtouint_from_user(s, count, base, res);
+}
+
+static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
+{
+	return kstrtoint_from_user(s, count, base, res);
+}
+
+/* internal, do not use */
 const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
 #endif
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -67,228 +67,6 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
 	return rv;
 }
 
-/**
- * kstrtoull - convert a string to an unsigned long long
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign, but not a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
- */
-int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
-{
-	unsigned long long _res;
-	int rv;
-
-	rv = parse_integer(s, base, &_res);
-	if (rv < 0)
-		return rv;
-	s += rv;
-	if (*s == '\n')
-		s++;
-	if (*s)
-		return -EINVAL;
-	*res = _res;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtoull);
-
-/**
- * kstrtoll - convert a string to a long long
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign or a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
- */
-int kstrtoll(const char *s, unsigned int base, long long *res)
-{
-	long long _res;
-	int rv;
-
-	rv = parse_integer(s, base, &_res);
-	if (rv < 0)
-		return rv;
-	s += rv;
-	if (*s == '\n')
-		s++;
-	if (*s)
-		return -EINVAL;
-	*res = _res;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtoll);
-
-/* Internal, do not use. */
-int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
-{
-	unsigned long long tmp;
-	int rv;
-
-	rv = kstrtoull(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (unsigned long long)(unsigned long)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(_kstrtoul);
-
-/* Internal, do not use. */
-int _kstrtol(const char *s, unsigned int base, long *res)
-{
-	long long tmp;
-	int rv;
-
-	rv = kstrtoll(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (long long)(long)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(_kstrtol);
-
-/**
- * kstrtouint - convert a string to an unsigned int
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign, but not a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
- */
-int kstrtouint(const char *s, unsigned int base, unsigned int *res)
-{
-	unsigned long long tmp;
-	int rv;
-
-	rv = kstrtoull(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (unsigned long long)(unsigned int)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtouint);
-
-/**
- * kstrtoint - convert a string to an int
- * @s: The start of the string. The string must be null-terminated, and may also
- *  include a single newline before its terminating null. The first character
- *  may also be a plus sign or a minus sign.
- * @base: The number base to use. The maximum supported base is 16. If base is
- *  given as 0, then the base of the string is automatically detected with the
- *  conventional semantics - If it begins with 0x the number will be parsed as a
- *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
- *  parsed as an octal number. Otherwise it will be parsed as a decimal.
- * @res: Where to write the result of the conversion on success.
- *
- * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
- * Used as a replacement for the obsolete simple_strtoull. Return code must
- * be checked.
- */
-int kstrtoint(const char *s, unsigned int base, int *res)
-{
-	long long tmp;
-	int rv;
-
-	rv = kstrtoll(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (long long)(int)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtoint);
-
-int kstrtou16(const char *s, unsigned int base, u16 *res)
-{
-	unsigned long long tmp;
-	int rv;
-
-	rv = kstrtoull(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (unsigned long long)(u16)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtou16);
-
-int kstrtos16(const char *s, unsigned int base, s16 *res)
-{
-	long long tmp;
-	int rv;
-
-	rv = kstrtoll(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (long long)(s16)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtos16);
-
-int kstrtou8(const char *s, unsigned int base, u8 *res)
-{
-	unsigned long long tmp;
-	int rv;
-
-	rv = kstrtoull(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (unsigned long long)(u8)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtou8);
-
-int kstrtos8(const char *s, unsigned int base, s8 *res)
-{
-	long long tmp;
-	int rv;
-
-	rv = kstrtoll(s, base, &tmp);
-	if (rv < 0)
-		return rv;
-	if (tmp != (long long)(s8)tmp)
-		return -ERANGE;
-	*res = tmp;
-	return 0;
-}
-EXPORT_SYMBOL(kstrtos8);
-
 #define kstrto_from_user(f, g, type)					\
 int f(const char __user *s, size_t count, unsigned int base, type *res)	\
 {									\
--- a/lib/parse-integer.c
+++ b/lib/parse-integer.c
@@ -31,7 +31,7 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
 	return s;
 }
 
-static int __parse_integer(const char *s, unsigned int base, unsigned long long *val)
+static int ___parse_integer(const char *s, unsigned int base, unsigned long long *val)
 {
 	const char *s0 = s, *sd;
 	unsigned long long acc;
@@ -63,6 +63,27 @@ static int __parse_integer(const char *s, unsigned int base, unsigned long long
 	return s - s0;
 }
 
+static int __parse_integer(const char *s, unsigned int base, unsigned long long *val)
+{
+	if (base & PARSE_INTEGER_NEWLINE) {
+		unsigned long long _val;
+		int rv;
+
+		/* Accept "integer\0" or "integer\n\0" */
+		rv = ___parse_integer(s, base & ~PARSE_INTEGER_NEWLINE, &_val);
+		if (rv < 0)
+			return rv;
+		s += rv;
+		if (*s == '\n')
+			s++;
+		if (*s)
+			return -EINVAL;
+		*val = _val;
+		return 0;
+	} else
+		return ___parse_integer(s, base, val);
+}
+
 int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val)
 {
 	int rv;
@@ -73,7 +94,10 @@ int _parse_integer_ull(const char *s, unsigned int base, unsigned long long *val
 		rv = __parse_integer(s + 1, base, val);
 		if (rv < 0)
 			return rv;
-		return rv + 1;
+		if (base & PARSE_INTEGER_NEWLINE)
+			return 0;
+		else
+			return rv + 1;
 	} else
 		return __parse_integer(s, base, val);
 }
@@ -91,7 +115,10 @@ int _parse_integer_ll(const char *s, unsigned int base, long long *val)
 		if ((long long)-tmp >= 0)
 			return -ERANGE;
 		*val = -tmp;
-		return rv + 1;
+		if (base & PARSE_INTEGER_NEWLINE)
+			return 0;
+		else
+			return rv + 1;
 	} else if (*s == '+') {
 		rv = __parse_integer(s + 1, base, &tmp);
 		if (rv < 0)
@@ -99,7 +126,10 @@ int _parse_integer_ll(const char *s, unsigned int base, long long *val)
 		if ((long long)tmp < 0)
 			return -ERANGE;
 		*val = tmp;
-		return rv + 1;
+		if (base & PARSE_INTEGER_NEWLINE)
+			return 0;
+		else
+			return rv + 1;
 	} else {
 		rv = __parse_integer(s, base, &tmp);
 		if (rv < 0)
-- 
2.0.4