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-rw-r--r--lib/kstrtox.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index 7a94c8f14e29..b1dd3e7d88cb 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -44,12 +44,13 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
*
* Don't you dare use this function.
*/
-unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res)
+unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
{
+ unsigned long long res;
unsigned int rv;
int overflow;
- *res = 0;
+ res = 0;
rv = 0;
overflow = 0;
while (*s) {
@@ -64,12 +65,19 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
if (val >= base)
break;
- if (*res > div_u64(ULLONG_MAX - val, base))
- overflow = 1;
- *res = *res * base + val;
+ /*
+ * Check for overflow only if we are within range of
+ * it in the max base we support (16)
+ */
+ if (unlikely(res & (~0ull << 60))) {
+ if (res > div_u64(ULLONG_MAX - val, base))
+ overflow = 1;
+ }
+ res = res * base + val;
rv++;
s++;
}
+ *p = res;
if (overflow)
rv |= KSTRTOX_OVERFLOW;
return rv;

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