[PATCH v5 0/5] lib: rework bitmap_parselist and tests

[PATCH v5 0/5] lib: rework bitmap_parselist and tests

[Yury Norov]

bitmap_parselist has been evolved from a pretty simple idea for long and
now lacks for refactoring. It is not structured, has nested loops and a
set of opaque-named variables.

Things are more complicated because bitmap_parselist() is a part of user
interface, and its behavior should not change.

In this patchset
 - bitmap_parselist_user() made a wrapper on bitmap_parselist();
 - bitmap_parselist() reworked (patch 2);
 - time measurement in test_bitmap_parselist switched to ktime_get
   (patch 3);
 - new tests introduced (patch 4), and
 - bitmap_parselist_user() testing enabled with the same testset as
   bitmap_parselist() (patch 5).


v1: https://lkml.org/lkml/2018/12/23/50
v2: https://www.spinics.net/lists/kernel/msg3048976.html
v3: https://lkml.org/lkml/2019/4/3/68
v4: https://lkml.org/lkml/2019/4/5/640
v5: - fix sadly missed '* step' in patch 4, as spotted by Guenter Roeck;
    - use _parse_integer() in bitmap_getnum() to avoid opencoding
      mentioned by Andy Shevchenko.

Yury Norov (5):
  lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()
  lib: rework bitmap_parselist
  lib/test_bitmap: switch test_bitmap_parselist to ktime_get()
  lib/test_bitmap: add testcases for bitmap_parselist
  lib/test_bitmap: add tests for bitmap_parselist_user

 lib/bitmap.c      | 274 ++++++++++++++++++++++++++--------------------
 lib/test_bitmap.c |  67 +++++++++---
 2 files changed, 207 insertions(+), 134 deletions(-)

-- 
2.17.1

[PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Yury Norov]

From: Yury Norov <ynorov@marvell.com>

Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm. The only user of
bitmap_parselist_user() is not performance-critical, and so we
can duplicate user data to kernel buffer and simply call
bitmap_parselist(). This rework lets us unify and simplify
bitmap_parselist() and bitmap_parselist_user(), which is done
in the following patch.

Signed-off-by: Yury Norov <ynorov@marvell.com>
---
 lib/bitmap.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 3f3b8051f342..c63ddd06a5da 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist);
  * @nmaskbits: size of bitmap, in bits.
  *
  * Wrapper for bitmap_parselist(), providing it with user buffer.
- *
- * We cannot have this as an inline function in bitmap.h because it needs
- * linux/uaccess.h to get the access_ok() declaration and this causes
- * cyclic dependencies.
  */
 int bitmap_parselist_user(const char __user *ubuf,
 			unsigned int ulen, unsigned long *maskp,
 			int nmaskbits)
 {
-	if (!access_ok(ubuf, ulen))
-		return -EFAULT;
-	return __bitmap_parselist((const char __force *)ubuf,
-					ulen, 1, maskp, nmaskbits);
+	char *buf;
+	int ret;
+
+	buf = memdup_user_nul(ubuf, ulen);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	ret = bitmap_parselist(buf, maskp, nmaskbits);
+
+	kfree(buf);
+	return ret;
 }
 EXPORT_SYMBOL(bitmap_parselist_user);
 
-- 
2.17.1

[PATCH 2/5] lib: rework bitmap_parselist

[Yury Norov]

From: Yury Norov <ynorov@marvell.com>

Remove __bitmap_parselist helper and split the function to logical
parts.

Signed-off-by: Yury Norov <ynorov@marvell.com>
---
 lib/bitmap.c | 255 ++++++++++++++++++++++++++++-----------------------
 1 file changed, 142 insertions(+), 113 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index c63ddd06a5da..f235434df87b 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -20,6 +20,8 @@
 
 #include <asm/page.h>
 
+#include "kstrtox.h"
+
 /**
  * DOC: bitmap introduction
  *
@@ -477,12 +479,128 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
 }
 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
 
+/*
+ * Region 9-38:4/10 describes the following bitmap structure:
+ * 0	   9  12    18			38
+ * .........****......****......****......
+ *	    ^  ^     ^			 ^
+ *      start  off   group_len	       end
+ */
+struct region {
+	unsigned int start;
+	unsigned int off;
+	unsigned int group_len;
+	unsigned int end;
+};
+
+static int bitmap_set_region(const struct region *r,
+				unsigned long *bitmap, int nbits)
+{
+	unsigned int start;
+
+	if (r->end >= nbits)
+		return -ERANGE;
+
+	for (start = r->start; start <= r->end; start += r->group_len)
+		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
+
+	return 0;
+}
+
+static int bitmap_check_region(const struct region *r)
+{
+	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const char *bitmap_getnum(const char *str, unsigned int *num)
+{
+	unsigned long long n;
+	unsigned int len;
+
+	len = _parse_integer(str, 10, &n);
+	if (!len)
+		return ERR_PTR(-EINVAL);
+	if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
+		return ERR_PTR(-EOVERFLOW);
+
+	*num = n;
+	return str + len;
+}
+
+static inline bool end_of_str(char c)
+{
+	return c == '\0' || c == '\n';
+}
+
+static inline bool __end_of_region(char c)
+{
+	return isspace(c) || c == ',';
+}
+
+static inline bool end_of_region(char c)
+{
+	return __end_of_region(c) || end_of_str(c);
+}
+
+/*
+ * The format allows commas and whitespases at the beginning
+ * of the region.
+ */
+static const char *bitmap_find_region(const char *str)
+{
+	while (__end_of_region(*str))
+		str++;
+
+	return end_of_str(*str) ? NULL : str;
+}
+
+static const char *bitmap_parse_region(const char *str, struct region *r)
+{
+	str = bitmap_getnum(str, &r->start);
+	if (IS_ERR(str))
+		return str;
+
+	if (end_of_region(*str))
+		goto no_end;
+
+	if (*str != '-')
+		return ERR_PTR(-EINVAL);
+
+	str = bitmap_getnum(str + 1, &r->end);
+	if (IS_ERR(str))
+		return str;
+
+	if (end_of_region(*str))
+		goto no_pattern;
+
+	if (*str != ':')
+		return ERR_PTR(-EINVAL);
+
+	str = bitmap_getnum(str + 1, &r->off);
+	if (IS_ERR(str))
+		return str;
+
+	if (*str != '/')
+		return ERR_PTR(-EINVAL);
+
+	return bitmap_getnum(str + 1, &r->group_len);
+
+no_end:
+	r->end = r->start;
+no_pattern:
+	r->off = r->end + 1;
+	r->group_len = r->end + 1;
+
+	return end_of_str(*str) ? NULL : str;
+}
+
 /**
- * __bitmap_parselist - convert list format ASCII string to bitmap
- * @buf: read nul-terminated user string from this buffer
- * @buflen: buffer size in bytes.  If string is smaller than this
- *    then it must be terminated with a \0.
- * @is_user: location of buffer, 0 indicates kernel space
+ * bitmap_parselist - convert list format ASCII string to bitmap
+ * @buf: read user string from this buffer; must be terminated
+ *    with a \0 or \n.
  * @maskp: write resulting mask here
  * @nmaskbits: number of bits in mask to be written
  *
@@ -498,127 +616,38 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
  *
  * Returns: 0 on success, -errno on invalid input strings. Error values:
  *
- *   - ``-EINVAL``: second number in range smaller than first
+ *   - ``-EINVAL``: wrong region format
  *   - ``-EINVAL``: invalid character in string
  *   - ``-ERANGE``: bit number specified too large for mask
+ *   - ``-EOVERFLOW``: integer overflow in the input parameters
  */
-static int __bitmap_parselist(const char *buf, unsigned int buflen,
-		int is_user, unsigned long *maskp,
-		int nmaskbits)
+int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 {
-	unsigned int a, b, old_a, old_b;
-	unsigned int group_size, used_size, off;
-	int c, old_c, totaldigits, ndigits;
-	const char __user __force *ubuf = (const char __user __force *)buf;
-	int at_start, in_range, in_partial_range;
+	struct region r;
+	long ret;
 
-	totaldigits = c = 0;
-	old_a = old_b = 0;
-	group_size = used_size = 0;
 	bitmap_zero(maskp, nmaskbits);
-	do {
-		at_start = 1;
-		in_range = 0;
-		in_partial_range = 0;
-		a = b = 0;
-		ndigits = totaldigits;
-
-		/* Get the next cpu# or a range of cpu#'s */
-		while (buflen) {
-			old_c = c;
-			if (is_user) {
-				if (__get_user(c, ubuf++))
-					return -EFAULT;
-			} else
-				c = *buf++;
-			buflen--;
-			if (isspace(c))
-				continue;
 
-			/* A '\0' or a ',' signal the end of a cpu# or range */
-			if (c == '\0' || c == ',')
-				break;
-			/*
-			* whitespaces between digits are not allowed,
-			* but it's ok if whitespaces are on head or tail.
-			* when old_c is whilespace,
-			* if totaldigits == ndigits, whitespace is on head.
-			* if whitespace is on tail, it should not run here.
-			* as c was ',' or '\0',
-			* the last code line has broken the current loop.
-			*/
-			if ((totaldigits != ndigits) && isspace(old_c))
-				return -EINVAL;
-
-			if (c == '/') {
-				used_size = a;
-				at_start = 1;
-				in_range = 0;
-				a = b = 0;
-				continue;
-			}
+	while (buf) {
+		buf = bitmap_find_region(buf);
+		if (buf == NULL)
+			return 0;
 
-			if (c == ':') {
-				old_a = a;
-				old_b = b;
-				at_start = 1;
-				in_range = 0;
-				in_partial_range = 1;
-				a = b = 0;
-				continue;
-			}
+		buf = bitmap_parse_region(buf, &r);
+		if (IS_ERR(buf))
+			return PTR_ERR(buf);
 
-			if (c == '-') {
-				if (at_start || in_range)
-					return -EINVAL;
-				b = 0;
-				in_range = 1;
-				at_start = 1;
-				continue;
-			}
+		ret = bitmap_check_region(&r);
+		if (ret)
+			return ret;
 
-			if (!isdigit(c))
-				return -EINVAL;
+		ret = bitmap_set_region(&r, maskp, nmaskbits);
+		if (ret)
+			return ret;
+	}
 
-			b = b * 10 + (c - '0');
-			if (!in_range)
-				a = b;
-			at_start = 0;
-			totaldigits++;
-		}
-		if (ndigits == totaldigits)
-			continue;
-		if (in_partial_range) {
-			group_size = a;
-			a = old_a;
-			b = old_b;
-			old_a = old_b = 0;
-		} else {
-			used_size = group_size = b - a + 1;
-		}
-		/* if no digit is after '-', it's wrong*/
-		if (at_start && in_range)
-			return -EINVAL;
-		if (!(a <= b) || group_size == 0 || !(used_size <= group_size))
-			return -EINVAL;
-		if (b >= nmaskbits)
-			return -ERANGE;
-		while (a <= b) {
-			off = min(b - a + 1, used_size);
-			bitmap_set(maskp, a, off);
-			a += group_size;
-		}
-	} while (buflen && c == ',');
 	return 0;
 }
-
-int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
-{
-	char *nl  = strchrnul(bp, '\n');
-	int len = nl - bp;
-
-	return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
-}
 EXPORT_SYMBOL(bitmap_parselist);
 
 
-- 
2.17.1

[PATCH 3/5] lib/test_bitmap: switch test_bitmap_parselist to ktime_get()

[Yury Norov]

From: Yury Norov <ynorov@marvell.com>

test_bitmap_parselist currently uses get_cycles which is not
implemented on some platforms, so use ktime_get() instead.

Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/test_bitmap.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 792d90608052..63d4a21955f0 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -268,15 +268,15 @@ static void __init test_bitmap_parselist(void)
 {
 	int i;
 	int err;
-	cycles_t cycles;
+	ktime_t time;
 	DECLARE_BITMAP(bmap, 2048);
 
 	for (i = 0; i < ARRAY_SIZE(parselist_tests); i++) {
 #define ptest parselist_tests[i]
 
-		cycles = get_cycles();
+		time = ktime_get();
 		err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
-		cycles = get_cycles() - cycles;
+		time = ktime_get() - time;
 
 		if (err != ptest.errno) {
 			pr_err("test %d: input is %s, errno is %d, expected %d\n",
@@ -293,8 +293,7 @@ static void __init test_bitmap_parselist(void)
 
 		if (ptest.flags & PARSE_TIME)
 			pr_err("test %d: input is '%s' OK, Time: %llu\n",
-					i, ptest.in,
-					(unsigned long long)cycles);
+					i, ptest.in, time);
 	}
 }
 
-- 
2.17.1

[PATCH 4/5] lib/test_bitmap: add testcases for bitmap_parselist

[Yury Norov]

From: Yury Norov <ynorov@marvell.com>

Add tests for non-number character, empty regions, integer overflow.

Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/test_bitmap.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 63d4a21955f0..6640a82ad44b 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -226,7 +226,8 @@ static const unsigned long exp[] __initconst = {
 	BITMAP_FROM_U64(0xffffffff),
 	BITMAP_FROM_U64(0xfffffffe),
 	BITMAP_FROM_U64(0x3333333311111111ULL),
-	BITMAP_FROM_U64(0xffffffff77777777ULL)
+	BITMAP_FROM_U64(0xffffffff77777777ULL),
+	BITMAP_FROM_U64(0),
 };
 
 static const unsigned long exp2[] __initconst = {
@@ -249,19 +250,34 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
 	{0, "1-31:4/4",			&exp[9 * step], 32, 0},
 	{0, "0-31:1/4,32-63:2/4",	&exp[10 * step], 64, 0},
 	{0, "0-31:3/4,32-63:4/4",	&exp[11 * step], 64, 0},
+	{0, "  ,,  0-31:3/4  ,, 32-63:4/4  ,,  ",	&exp[11 * step], 64, 0},
 
 	{0, "0-31:1/4,32-63:2/4,64-95:3/4,96-127:4/4",	exp2, 128, 0},
 
 	{0, "0-2047:128/256", NULL, 2048, PARSE_TIME},
 
+	{0, "",				&exp[12 * step], 8, 0},
+	{0, "\n",			&exp[12 * step], 8, 0},
+	{0, ",,  ,,  , ,  ,",		&exp[12 * step], 8, 0},
+	{0, " ,  ,,  , ,   ",		&exp[12 * step], 8, 0},
+	{0, " ,  ,,  , ,   \n",		&exp[12 * step], 8, 0},
+
 	{-EINVAL, "-1",	NULL, 8, 0},
 	{-EINVAL, "-0",	NULL, 8, 0},
 	{-EINVAL, "10-1", NULL, 8, 0},
 	{-EINVAL, "0-31:", NULL, 8, 0},
 	{-EINVAL, "0-31:0", NULL, 8, 0},
+	{-EINVAL, "0-31:0/", NULL, 8, 0},
 	{-EINVAL, "0-31:0/0", NULL, 8, 0},
 	{-EINVAL, "0-31:1/0", NULL, 8, 0},
 	{-EINVAL, "0-31:10/1", NULL, 8, 0},
+	{-EOVERFLOW, "0-98765432123456789:10/1", NULL, 8, 0},
+
+	{-EINVAL, "a-31", NULL, 8, 0},
+	{-EINVAL, "0-a1", NULL, 8, 0},
+	{-EINVAL, "a-31:10/1", NULL, 8, 0},
+	{-EINVAL, "0-31:a/1", NULL, 8, 0},
+	{-EINVAL, "0-\n", NULL, 8, 0},
 };
 
 static void __init test_bitmap_parselist(void)
-- 
2.17.1

[PATCH 5/5] lib/test_bitmap: add tests for bitmap_parselist_user

[Yury Norov]

From: Yury Norov <ynorov@marvell.com>

Propagate existing bitmap_parselist() tests to bitmap_parselist_user().

Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/test_bitmap.c | 46 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6640a82ad44b..d3a501f2a81a 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -11,6 +11,7 @@
 #include <linux/printk.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/uaccess.h>
 
 #include "../tools/testing/selftests/kselftest_module.h"
 
@@ -280,39 +281,63 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
 	{-EINVAL, "0-\n", NULL, 8, 0},
 };
 
-static void __init test_bitmap_parselist(void)
+static void __init __test_bitmap_parselist(int is_user)
 {
 	int i;
 	int err;
 	ktime_t time;
 	DECLARE_BITMAP(bmap, 2048);
+	char *mode = is_user ? "_user"  : "";
 
 	for (i = 0; i < ARRAY_SIZE(parselist_tests); i++) {
 #define ptest parselist_tests[i]
 
-		time = ktime_get();
-		err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
-		time = ktime_get() - time;
+		if (is_user) {
+			mm_segment_t orig_fs = get_fs();
+			size_t len = strlen(ptest.in);
+
+			set_fs(KERNEL_DS);
+			time = ktime_get();
+			err = bitmap_parselist_user(ptest.in, len,
+						    bmap, ptest.nbits);
+			time = ktime_get() - time;
+			set_fs(orig_fs);
+		} else {
+			time = ktime_get();
+			err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
+			time = ktime_get() - time;
+		}
 
 		if (err != ptest.errno) {
-			pr_err("test %d: input is %s, errno is %d, expected %d\n",
-					i, ptest.in, err, ptest.errno);
+			pr_err("parselist%s: %d: input is %s, errno is %d, expected %d\n",
+					mode, i, ptest.in, err, ptest.errno);
 			continue;
 		}
 
 		if (!err && ptest.expected
 			 && !__bitmap_equal(bmap, ptest.expected, ptest.nbits)) {
-			pr_err("test %d: input is %s, result is 0x%lx, expected 0x%lx\n",
-					i, ptest.in, bmap[0], *ptest.expected);
+			pr_err("parselist%s: %d: input is %s, result is 0x%lx, expected 0x%lx\n",
+					mode, i, ptest.in, bmap[0],
+					*ptest.expected);
 			continue;
 		}
 
 		if (ptest.flags & PARSE_TIME)
-			pr_err("test %d: input is '%s' OK, Time: %llu\n",
-					i, ptest.in, time);
+			pr_err("parselist%s: %d: input is '%s' OK, Time: %llu\n",
+					mode, i, ptest.in, time);
 	}
 }
 
+static void __init test_bitmap_parselist(void)
+{
+	__test_bitmap_parselist(0);
+}
+
+static void __init test_bitmap_parselist_user(void)
+{
+	__test_bitmap_parselist(1);
+}
+
 #define EXP_BYTES	(sizeof(exp) * 8)
 
 static void __init test_bitmap_arr32(void)
@@ -385,6 +410,7 @@ static void __init selftest(void)
 	test_copy();
 	test_bitmap_arr32();
 	test_bitmap_parselist();
+	test_bitmap_parselist_user();
 	test_mem_optimisations();
 }
 
-- 
2.17.1

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Andy Shevchenko]

On Mon, Apr 15, 2019 at 11:37:57PM -0700, Yury Norov wrote:
> From: Yury Norov <ynorov@marvell.com>
> 
> Currently we parse user data byte after byte which leads to
> overcomplification of parsing algorithm. The only user of
> bitmap_parselist_user() is not performance-critical, and so we
> can duplicate user data to kernel buffer and simply call
> bitmap_parselist(). This rework lets us unify and simplify
> bitmap_parselist() and bitmap_parselist_user(), which is done
> in the following patch.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> 
> Signed-off-by: Yury Norov <ynorov@marvell.com>
> ---
>  lib/bitmap.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 3f3b8051f342..c63ddd06a5da 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist);
>   * @nmaskbits: size of bitmap, in bits.
>   *
>   * Wrapper for bitmap_parselist(), providing it with user buffer.
> - *
> - * We cannot have this as an inline function in bitmap.h because it needs
> - * linux/uaccess.h to get the access_ok() declaration and this causes
> - * cyclic dependencies.
>   */
>  int bitmap_parselist_user(const char __user *ubuf,
>  			unsigned int ulen, unsigned long *maskp,
>  			int nmaskbits)
>  {
> -	if (!access_ok(ubuf, ulen))
> -		return -EFAULT;
> -	return __bitmap_parselist((const char __force *)ubuf,
> -					ulen, 1, maskp, nmaskbits);
> +	char *buf;
> +	int ret;
> +
> +	buf = memdup_user_nul(ubuf, ulen);
> +	if (IS_ERR(buf))
> +		return PTR_ERR(buf);
> +
> +	ret = bitmap_parselist(buf, maskp, nmaskbits);
> +
> +	kfree(buf);
> +	return ret;
>  }
>  EXPORT_SYMBOL(bitmap_parselist_user);
>  
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 2/5] lib: rework bitmap_parselist

[Andy Shevchenko]

On Mon, Apr 15, 2019 at 11:37:58PM -0700, Yury Norov wrote:
> From: Yury Norov <ynorov@marvell.com>
> 
> Remove __bitmap_parselist helper and split the function to logical
> parts.
> 

One comment below.

Overall looks good to me, thanks!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Yury Norov <ynorov@marvell.com>
> ---
>  lib/bitmap.c | 255 ++++++++++++++++++++++++++++-----------------------
>  1 file changed, 142 insertions(+), 113 deletions(-)
> 
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index c63ddd06a5da..f235434df87b 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -20,6 +20,8 @@
>  
>  #include <asm/page.h>
>  
> +#include "kstrtox.h"
> +
>  /**
>   * DOC: bitmap introduction
>   *
> @@ -477,12 +479,128 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
>  }
>  EXPORT_SYMBOL(bitmap_print_to_pagebuf);
>  
> +/*
> + * Region 9-38:4/10 describes the following bitmap structure:
> + * 0	   9  12    18			38
> + * .........****......****......****......
> + *	    ^  ^     ^			 ^
> + *      start  off   group_len	       end
> + */
> +struct region {
> +	unsigned int start;
> +	unsigned int off;
> +	unsigned int group_len;
> +	unsigned int end;
> +};
> +
> +static int bitmap_set_region(const struct region *r,
> +				unsigned long *bitmap, int nbits)
> +{
> +	unsigned int start;
> +
> +	if (r->end >= nbits)
> +		return -ERANGE;
> +
> +	for (start = r->start; start <= r->end; start += r->group_len)
> +		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
> +
> +	return 0;
> +}
> +
> +static int bitmap_check_region(const struct region *r)
> +{
> +	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static const char *bitmap_getnum(const char *str, unsigned int *num)
> +{
> +	unsigned long long n;
> +	unsigned int len;
> +

> +	len = _parse_integer(str, 10, &n);

I think we are good here, since it's only for use inside lib itself.

> +	if (!len)
> +		return ERR_PTR(-EINVAL);

> +	if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)

Second part is simple to compare to UINT_MAX: "n > UINT_MAX", or
"upper_32_bits(n)" would work as well.

Among all I would rather go to comparison with limits, i.e. UINT_MAX.

> +		return ERR_PTR(-EOVERFLOW);
> +
> +	*num = n;
> +	return str + len;
> +}
> +
> +static inline bool end_of_str(char c)
> +{
> +	return c == '\0' || c == '\n';
> +}
> +
> +static inline bool __end_of_region(char c)
> +{
> +	return isspace(c) || c == ',';
> +}
> +
> +static inline bool end_of_region(char c)
> +{
> +	return __end_of_region(c) || end_of_str(c);
> +}
> +
> +/*
> + * The format allows commas and whitespases at the beginning
> + * of the region.
> + */
> +static const char *bitmap_find_region(const char *str)
> +{
> +	while (__end_of_region(*str))
> +		str++;
> +
> +	return end_of_str(*str) ? NULL : str;
> +}
> +
> +static const char *bitmap_parse_region(const char *str, struct region *r)
> +{
> +	str = bitmap_getnum(str, &r->start);
> +	if (IS_ERR(str))
> +		return str;
> +
> +	if (end_of_region(*str))
> +		goto no_end;
> +
> +	if (*str != '-')
> +		return ERR_PTR(-EINVAL);
> +
> +	str = bitmap_getnum(str + 1, &r->end);
> +	if (IS_ERR(str))
> +		return str;
> +
> +	if (end_of_region(*str))
> +		goto no_pattern;
> +
> +	if (*str != ':')
> +		return ERR_PTR(-EINVAL);
> +
> +	str = bitmap_getnum(str + 1, &r->off);
> +	if (IS_ERR(str))
> +		return str;
> +
> +	if (*str != '/')
> +		return ERR_PTR(-EINVAL);
> +
> +	return bitmap_getnum(str + 1, &r->group_len);
> +
> +no_end:
> +	r->end = r->start;
> +no_pattern:
> +	r->off = r->end + 1;
> +	r->group_len = r->end + 1;
> +
> +	return end_of_str(*str) ? NULL : str;
> +}
> +
>  /**
> - * __bitmap_parselist - convert list format ASCII string to bitmap
> - * @buf: read nul-terminated user string from this buffer
> - * @buflen: buffer size in bytes.  If string is smaller than this
> - *    then it must be terminated with a \0.
> - * @is_user: location of buffer, 0 indicates kernel space
> + * bitmap_parselist - convert list format ASCII string to bitmap
> + * @buf: read user string from this buffer; must be terminated
> + *    with a \0 or \n.
>   * @maskp: write resulting mask here
>   * @nmaskbits: number of bits in mask to be written
>   *
> @@ -498,127 +616,38 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
>   *
>   * Returns: 0 on success, -errno on invalid input strings. Error values:
>   *
> - *   - ``-EINVAL``: second number in range smaller than first
> + *   - ``-EINVAL``: wrong region format
>   *   - ``-EINVAL``: invalid character in string
>   *   - ``-ERANGE``: bit number specified too large for mask
> + *   - ``-EOVERFLOW``: integer overflow in the input parameters
>   */
> -static int __bitmap_parselist(const char *buf, unsigned int buflen,
> -		int is_user, unsigned long *maskp,
> -		int nmaskbits)
> +int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
>  {
> -	unsigned int a, b, old_a, old_b;
> -	unsigned int group_size, used_size, off;
> -	int c, old_c, totaldigits, ndigits;
> -	const char __user __force *ubuf = (const char __user __force *)buf;
> -	int at_start, in_range, in_partial_range;
> +	struct region r;
> +	long ret;
>  
> -	totaldigits = c = 0;
> -	old_a = old_b = 0;
> -	group_size = used_size = 0;
>  	bitmap_zero(maskp, nmaskbits);
> -	do {
> -		at_start = 1;
> -		in_range = 0;
> -		in_partial_range = 0;
> -		a = b = 0;
> -		ndigits = totaldigits;
> -
> -		/* Get the next cpu# or a range of cpu#'s */
> -		while (buflen) {
> -			old_c = c;
> -			if (is_user) {
> -				if (__get_user(c, ubuf++))
> -					return -EFAULT;
> -			} else
> -				c = *buf++;
> -			buflen--;
> -			if (isspace(c))
> -				continue;
>  
> -			/* A '\0' or a ',' signal the end of a cpu# or range */
> -			if (c == '\0' || c == ',')
> -				break;
> -			/*
> -			* whitespaces between digits are not allowed,
> -			* but it's ok if whitespaces are on head or tail.
> -			* when old_c is whilespace,
> -			* if totaldigits == ndigits, whitespace is on head.
> -			* if whitespace is on tail, it should not run here.
> -			* as c was ',' or '\0',
> -			* the last code line has broken the current loop.
> -			*/
> -			if ((totaldigits != ndigits) && isspace(old_c))
> -				return -EINVAL;
> -
> -			if (c == '/') {
> -				used_size = a;
> -				at_start = 1;
> -				in_range = 0;
> -				a = b = 0;
> -				continue;
> -			}
> +	while (buf) {
> +		buf = bitmap_find_region(buf);
> +		if (buf == NULL)
> +			return 0;
>  
> -			if (c == ':') {
> -				old_a = a;
> -				old_b = b;
> -				at_start = 1;
> -				in_range = 0;
> -				in_partial_range = 1;
> -				a = b = 0;
> -				continue;
> -			}
> +		buf = bitmap_parse_region(buf, &r);
> +		if (IS_ERR(buf))
> +			return PTR_ERR(buf);
>  
> -			if (c == '-') {
> -				if (at_start || in_range)
> -					return -EINVAL;
> -				b = 0;
> -				in_range = 1;
> -				at_start = 1;
> -				continue;
> -			}
> +		ret = bitmap_check_region(&r);
> +		if (ret)
> +			return ret;
>  
> -			if (!isdigit(c))
> -				return -EINVAL;
> +		ret = bitmap_set_region(&r, maskp, nmaskbits);
> +		if (ret)
> +			return ret;
> +	}
>  
> -			b = b * 10 + (c - '0');
> -			if (!in_range)
> -				a = b;
> -			at_start = 0;
> -			totaldigits++;
> -		}
> -		if (ndigits == totaldigits)
> -			continue;
> -		if (in_partial_range) {
> -			group_size = a;
> -			a = old_a;
> -			b = old_b;
> -			old_a = old_b = 0;
> -		} else {
> -			used_size = group_size = b - a + 1;
> -		}
> -		/* if no digit is after '-', it's wrong*/
> -		if (at_start && in_range)
> -			return -EINVAL;
> -		if (!(a <= b) || group_size == 0 || !(used_size <= group_size))
> -			return -EINVAL;
> -		if (b >= nmaskbits)
> -			return -ERANGE;
> -		while (a <= b) {
> -			off = min(b - a + 1, used_size);
> -			bitmap_set(maskp, a, off);
> -			a += group_size;
> -		}
> -	} while (buflen && c == ',');
>  	return 0;
>  }
> -
> -int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
> -{
> -	char *nl  = strchrnul(bp, '\n');
> -	int len = nl - bp;
> -
> -	return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
> -}
>  EXPORT_SYMBOL(bitmap_parselist);
>  
>  
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Andy Shevchenko]

On Fri, Apr 05, 2019 at 08:32:07PM +0300, Yury Norov wrote:
> Currently we parse user data byte after byte which leads to
> overcomplification of parsing algorithm. The only user of
> bitmap_parselist_user() is not performance-critical, and so we
> can duplicate user data to kernel buffer and simply call
> bitmap_parselist(). This rework lets us unify and simplify
> bitmap_parselist() and bitmap_parselist_user(), which is done
> in the following patch.
> 

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Yury Norov <ynorov@marvell.com>
> ---
>  lib/bitmap.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 98872e9025da..79ed5538617b 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist);
>   * @nmaskbits: size of bitmap, in bits.
>   *
>   * Wrapper for bitmap_parselist(), providing it with user buffer.
> - *
> - * We cannot have this as an inline function in bitmap.h because it needs
> - * linux/uaccess.h to get the access_ok() declaration and this causes
> - * cyclic dependencies.
>   */
>  int bitmap_parselist_user(const char __user *ubuf,
>  			unsigned int ulen, unsigned long *maskp,
>  			int nmaskbits)
>  {
> -	if (!access_ok(ubuf, ulen))
> -		return -EFAULT;
> -	return __bitmap_parselist((const char __force *)ubuf,
> -					ulen, 1, maskp, nmaskbits);
> +	char *buf;
> +	int ret;
> +
> +	buf = memdup_user_nul(ubuf, ulen);
> +	if (IS_ERR(buf))
> +		return PTR_ERR(buf);
> +
> +	ret = bitmap_parselist(buf, maskp, nmaskbits);
> +
> +	kfree(buf);
> +	return ret;
>  }
>  EXPORT_SYMBOL(bitmap_parselist_user);
>  
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko

[PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Yury Norov]

Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm. The only user of
bitmap_parselist_user() is not performance-critical, and so we
can duplicate user data to kernel buffer and simply call
bitmap_parselist(). This rework lets us unify and simplify
bitmap_parselist() and bitmap_parselist_user(), which is done
in the following patch.

Signed-off-by: Yury Norov <ynorov@marvell.com>
---
 lib/bitmap.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 98872e9025da..79ed5538617b 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist);
  * @nmaskbits: size of bitmap, in bits.
  *
  * Wrapper for bitmap_parselist(), providing it with user buffer.
- *
- * We cannot have this as an inline function in bitmap.h because it needs
- * linux/uaccess.h to get the access_ok() declaration and this causes
- * cyclic dependencies.
  */
 int bitmap_parselist_user(const char __user *ubuf,
 			unsigned int ulen, unsigned long *maskp,
 			int nmaskbits)
 {
-	if (!access_ok(ubuf, ulen))
-		return -EFAULT;
-	return __bitmap_parselist((const char __force *)ubuf,
-					ulen, 1, maskp, nmaskbits);
+	char *buf;
+	int ret;
+
+	buf = memdup_user_nul(ubuf, ulen);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	ret = bitmap_parselist(buf, maskp, nmaskbits);
+
+	kfree(buf);
+	return ret;
 }
 EXPORT_SYMBOL(bitmap_parselist_user);
 
-- 
2.17.1

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Andy Shevchenko]

On Wed, Apr 03, 2019 at 02:17:39PM +0200, Rasmus Villemoes wrote:
> On 03/04/2019 13.17, Andy Shevchenko wrote:
> > On Wed, Apr 03, 2019 at 02:15:22PM +0300, Andy Shevchenko wrote:
> >> On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote:
> >>> Currently we parse user data byte after byte which leads to
> >>> overcomplification of parsing algorithm. The only user of
> >>> bitmap_parselist_user() is not performance-critical, and so we
> >>> can copy user data to kernel buffer and simply call
> >>> bitmap_parselist(). This rework lets us unify and simplify
> >>> bitmap_parselist() and bitmap_parselist_user(), which is done
> >>> in the following patch.
> >>
> >>> +	buf = kmalloc(ulen + 1, GFP_KERNEL);
> >>> +	if (!buf)
> >>> +		return -ENOMEM;
> >>> +
> >>> +	buf[ulen] = 0;
> >>> +
> >>> +	ret = copy_from_user(buf, ubuf, ulen);
> >>> +	if (ret)
> >>> +		goto out;
> >>
> >> Why not memdup_user() ?
> > 
> > Even more precisely (for strings) strndup_user().
> > 
> 
> But the user buffer is not nul-terminated, i.e. it's not a string. 

Missed that. I stand corrected.

> What
> you want is memdup_user_nul() - take a length-delimited user buffer and
> turn it into a nul-terminated string in kernel memory.

Good, we have a helper.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Rasmus Villemoes]

On 03/04/2019 13.17, Andy Shevchenko wrote:
> On Wed, Apr 03, 2019 at 02:15:22PM +0300, Andy Shevchenko wrote:
>> On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote:
>>> Currently we parse user data byte after byte which leads to
>>> overcomplification of parsing algorithm. The only user of
>>> bitmap_parselist_user() is not performance-critical, and so we
>>> can copy user data to kernel buffer and simply call
>>> bitmap_parselist(). This rework lets us unify and simplify
>>> bitmap_parselist() and bitmap_parselist_user(), which is done
>>> in the following patch.
>>
>>> +	buf = kmalloc(ulen + 1, GFP_KERNEL);
>>> +	if (!buf)
>>> +		return -ENOMEM;
>>> +
>>> +	buf[ulen] = 0;
>>> +
>>> +	ret = copy_from_user(buf, ubuf, ulen);
>>> +	if (ret)
>>> +		goto out;
>>
>> Why not memdup_user() ?
> 
> Even more precisely (for strings) strndup_user().
> 

But the user buffer is not nul-terminated, i.e. it's not a string. What
you want is memdup_user_nul() - take a length-delimited user buffer and
turn it into a nul-terminated string in kernel memory. And yes, please
use that.

Rasmus

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Andy Shevchenko]

On Wed, Apr 03, 2019 at 02:15:22PM +0300, Andy Shevchenko wrote:
> On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote:
> > Currently we parse user data byte after byte which leads to
> > overcomplification of parsing algorithm. The only user of
> > bitmap_parselist_user() is not performance-critical, and so we
> > can copy user data to kernel buffer and simply call
> > bitmap_parselist(). This rework lets us unify and simplify
> > bitmap_parselist() and bitmap_parselist_user(), which is done
> > in the following patch.
> 
> > +	buf = kmalloc(ulen + 1, GFP_KERNEL);
> > +	if (!buf)
> > +		return -ENOMEM;
> > +
> > +	buf[ulen] = 0;
> > +
> > +	ret = copy_from_user(buf, ubuf, ulen);
> > +	if (ret)
> > +		goto out;
> 
> Why not memdup_user() ?

Even more precisely (for strings) strndup_user().

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Andy Shevchenko]

On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote:
> Currently we parse user data byte after byte which leads to
> overcomplification of parsing algorithm. The only user of
> bitmap_parselist_user() is not performance-critical, and so we
> can copy user data to kernel buffer and simply call
> bitmap_parselist(). This rework lets us unify and simplify
> bitmap_parselist() and bitmap_parselist_user(), which is done
> in the following patch.

> +	buf = kmalloc(ulen + 1, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	buf[ulen] = 0;
> +
> +	ret = copy_from_user(buf, ubuf, ulen);
> +	if (ret)
> +		goto out;

Why not memdup_user() ?

-- 
With Best Regards,
Andy Shevchenko

[PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

[Yury Norov]

Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm. The only user of
bitmap_parselist_user() is not performance-critical, and so we
can copy user data to kernel buffer and simply call
bitmap_parselist(). This rework lets us unify and simplify
bitmap_parselist() and bitmap_parselist_user(), which is done
in the following patch.

Signed-off-by: Yury Norov <ynorov@marvell.com>
---
 lib/bitmap.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 98872e9025da..ce9ea804d06d 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -632,19 +632,30 @@ EXPORT_SYMBOL(bitmap_parselist);
  * @nmaskbits: size of bitmap, in bits.
  *
  * Wrapper for bitmap_parselist(), providing it with user buffer.
- *
- * We cannot have this as an inline function in bitmap.h because it needs
- * linux/uaccess.h to get the access_ok() declaration and this causes
- * cyclic dependencies.
  */
 int bitmap_parselist_user(const char __user *ubuf,
 			unsigned int ulen, unsigned long *maskp,
 			int nmaskbits)
 {
-	if (!access_ok(ubuf, ulen))
-		return -EFAULT;
-	return __bitmap_parselist((const char __force *)ubuf,
-					ulen, 1, maskp, nmaskbits);
+	char *buf;
+	int ret;
+
+	buf = kmalloc(ulen + 1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf[ulen] = 0;
+
+	ret = copy_from_user(buf, ubuf, ulen);
+	if (ret)
+		goto out;
+
+	ret = bitmap_parselist(buf, maskp, nmaskbits);
+
+out:
+	kfree(buf);
+
+	return ret;
 }
 EXPORT_SYMBOL(bitmap_parselist_user);
 
-- 
2.17.1