1 files changed, 17 insertions, 15 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 64c0926f5dd8..a578a0189199 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -462,19 +462,20 @@ EXPORT_SYMBOL(bitmap_parse_user);
  * Output format is a comma-separated list of decimal numbers and
  * ranges if list is specified or hex digits grouped into comma-separated
  * sets of 8 digits/set. Returns the number of characters written to buf.
+ *
+ * It is assumed that @buf is a pointer into a PAGE_SIZE area and that
+ * sufficient storage remains at @buf to accommodate the
+ * bitmap_print_to_pagebuf() output.
  */
 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
                             int nmaskbits)
 {
-        ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf - 2;
+        ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf;
         int n = 0;
 
-        if (len > 1) {
-                n = list ? scnprintf(buf, len, "%*pbl", nmaskbits, maskp) :
-                           scnprintf(buf, len, "%*pb", nmaskbits, maskp);
-                buf[n++] = '\n';
-                buf[n] = '\0';
-        }
+        if (len > 1)
+                n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
+                           scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
         return n;
 }
 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
@@ -506,12 +507,12 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
         unsigned a, b;
         int c, old_c, totaldigits;
         const char __user __force *ubuf = (const char __user __force *)buf;
-        int exp_digit, in_range;
+        int at_start, in_range;
 
         totaldigits = c = 0;
         bitmap_zero(maskp, nmaskbits);
         do {
-                exp_digit = 1;
+                at_start = 1;
                 in_range = 0;
                 a = b = 0;
 
@@ -540,11 +541,10 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
                                 break;
 
                         if (c == '-') {
-                                if (exp_digit || in_range)
+                                if (at_start || in_range)
                                         return -EINVAL;
                                 b = 0;
                                 in_range = 1;
-                                exp_digit = 1;
                                 continue;
                         }
 
@@ -554,16 +554,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
                         b = b * 10 + (c - '0');
                         if (!in_range)
                                 a = b;
-                        exp_digit = 0;
+                        at_start = 0;
                         totaldigits++;
                 }
                 if (!(a <= b))
                         return -EINVAL;
                 if (b >= nmaskbits)
                         return -ERANGE;
-                while (a <= b) {
-                        set_bit(a, maskp);
-                        a++;
+                if (!at_start) {
+                        while (a <= b) {
+                                set_bit(a, maskp);
+                                a++;
+                        }
                 }
         } while (buflen && c == ',');
         return 0;