Skip to contentSkip to conversation

lib/bitmap.c: correct a code style and do some, optimization

PATCH RESEND New Pan Xinhui 1 participant 3 messages Jul 1, 2015

Subsystems (2)
Library code Bitmap API
lore
Share & tools
lore

Pan Xinhui

author
#0 lore raw

PATCH RESEND 1/3 lib/bitmap.c: correct a code style and do some, optimization

We can avoid in-loop incrementation of ndigits. Save current totaldigits to ndigits before loop, and check ndigits against totaldigits after the loop.

Signed-off-by Pan Xinhui <[email protected]>
Cc Yury Norov <[email protected]>
---
 lib/bitmap.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
lib/bitmap.c +4 -3
index a578a01..eb21456 100644
@@ -367,7 +367,8 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
 
 	nchunks = nbits = totaldigits = c = 0;
 	do {
-		chunk = ndigits = 0;
+		chunk = 0;
+		ndigits = totaldigits;
 
 		/* Get the next chunk of the bitmap */
 		while (buflen) {

@@ -406,9 +407,9 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
 				return -EOVERFLOW;
 
 			chunk = (chunk << 4) | hex_to_bin(c);
-			ndigits++; totaldigits++;
+			totaldigits++;
 		}
-		if (ndigits == 0)
+		if (ndigits == totaldigits)
 			return -EINVAL;
 		if (nchunks == 0 && chunk == 0)
 			continue;
Signature · 1 line
1.9.1
author
#1 lore raw

PATCH RESEND 2/3 lib/bitmap.c: fix a special string handling bug in __bitmap_parselist

If string end with '-', for exapmle, bitmap_parselist("1,0-",&mask, nmaskbits), It is not in a valid pattern, so add a check after loop.
Return -EINVAL on such condition.

Signed-off-by Pan Xinhui <[email protected]>
---
 lib/bitmap.c | 4 ++++
 1 file changed, 4 insertions(+)
lib/bitmap.c +4 -0
index eb21456..f549176 100644
@@ -546,6 +546,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 					return -EINVAL;
 				b = 0;
 				in_range = 1;
+				at_start = 1;
 				continue;
 			}
 

@@ -558,6 +559,9 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 			at_start = 0;
 			totaldigits++;
 		}
+		/* if no digit is after '-', it's wrong*/
+		if (at_start && in_range)
+			return -EINVAL;
 		if (!(a <= b))
 			return -EINVAL;
 		if (b >= nmaskbits)
Signature · 1 line
1.9.1
author
#2 lore raw

PATCH RESEND 3/3 lib/bitmap.c: bitmap_parselist can accept string with whitespaces on head or tail

In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure.
If input has valid ranges, there is no reason to reject the user.

For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After separating the string, we get " 1-3", " 5", and " ". It's possible and reasonable to accept such string as long as the parsing result is correct.

Signed-off-by Pan Xinhui <[email protected]>
Cc Yury Norov <[email protected]>
---
 lib/bitmap.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)
lib/bitmap.c +18 -14
index f549176..8148143 100644
@@ -506,7 +506,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 		int nmaskbits)
 {
 	unsigned a, b;
-	int c, old_c, totaldigits;
+	int c, old_c, totaldigits, ndigits;
 	const char __user __force *ubuf = (const char __user __force *)buf;
 	int at_start, in_range;
 

@@ -516,6 +516,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 		at_start = 1;
 		in_range = 0;
 		a = b = 0;
+		ndigits = totaldigits;
 
 		/* Get the next cpu# or a range of cpu#'s */
 		while (buflen) {

@@ -529,17 +530,20 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 			if (isspace(c))
 				continue;
 
-			/*
-			 * If the last character was a space and the current
-			 * character isn't '\0', we've got embedded whitespace.
-			 * This is a no-no, so throw an error.
-			 */
-			if (totaldigits && c && isspace(old_c))
-				return -EINVAL;
-
 			/* 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 == '-') {
 				if (at_start || in_range)

@@ -559,6 +563,8 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 			at_start = 0;
 			totaldigits++;
 		}
+		if (ndigits == totaldigits)
+			continue;
 		/* if no digit is after '-', it's wrong*/
 		if (at_start && in_range)
 			return -EINVAL;

@@ -566,11 +572,9 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 			return -EINVAL;
 		if (b >= nmaskbits)
 			return -ERANGE;
-		if (!at_start) {
-			while (a <= b) {
-				set_bit(a, maskp);
-				a++;
-			}
+		while (a <= b) {
+			set_bit(a, maskp);
+			a++;
 		}
 	} while (buflen && c == ',');
 	return 0;
Signature · 1 line
1.9.1