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-rw-r--r--drivers/md/md.c64
1 files changed, 42 insertions, 22 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c56c64d1307..93287f88f1f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2763,6 +2763,47 @@ static void analyze_sbs(mddev_t * mddev)
}
}
+/* Read a fixed-point number.
+ * Numbers in sysfs attributes should be in "standard" units where
+ * possible, so time should be in seconds.
+ * However we internally use a a much smaller unit such as
+ * milliseconds or jiffies.
+ * This function takes a decimal number with a possible fractional
+ * component, and produces an integer which is the result of
+ * multiplying that number by 10^'scale'.
+ * all without any floating-point arithmetic.
+ */
+int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
+{
+ unsigned long result = 0;
+ long decimals = -1;
+ while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
+ if (*cp == '.')
+ decimals = 0;
+ else if (decimals < scale) {
+ unsigned int value;
+ value = *cp - '0';
+ result = result * 10 + value;
+ if (decimals >= 0)
+ decimals++;
+ }
+ cp++;
+ }
+ if (*cp == '\n')
+ cp++;
+ if (*cp)
+ return -EINVAL;
+ if (decimals < 0)
+ decimals = 0;
+ while (decimals < scale) {
+ result *= 10;
+ decimals ++;
+ }
+ *res = result;
+ return 0;
+}
+
+
static void md_safemode_timeout(unsigned long data);
static ssize_t
@@ -2774,31 +2815,10 @@ safe_delay_show(mddev_t *mddev, char *page)
static ssize_t
safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
{
- int scale=1;
- int dot=0;
- int i;
unsigned long msec;
- char buf[30];
- /* remove a period, and count digits after it */
- if (len >= sizeof(buf))
- return -EINVAL;
- strlcpy(buf, cbuf, sizeof(buf));
- for (i=0; i<len; i++) {
- if (dot) {
- if (isdigit(buf[i])) {
- buf[i-1] = buf[i];
- scale *= 10;
- }
- buf[i] = 0;
- } else if (buf[i] == '.') {
- dot=1;
- buf[i] = 0;
- }
- }
- if (strict_strtoul(buf, 10, &msec) < 0)
+ if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
return -EINVAL;
- msec = (msec * 1000) / scale;
if (msec == 0)
mddev->safemode_delay = 0;
else {