[SCSI] lib: string_get_size(): don't hang on zero; no decimals on exact

We would hang forever when passing a zero to string_get_size().
Furthermore, string_get_size() would produce decimals on a value small
enough to be exact.  Finally, a few formatting issues are inconsistent
with standard SI style guidelines.

- If the value is less than the divisor, skip the entire rounding
  step.  This prints out all small values including zero as integers,
  without decimals.
- Add a space between the value and the symbol for the unit,
  consistent with standard SI practice.
- Lower case k in kB since we are talking about powers of 10.
- Finally, change "int" to "unsigned int" in one place to shut up a
  gcc warning when compiling the code out-of-kernel for testing.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 19 insertions, 15 deletions

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 8347925030ff..ab431d4cc970 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -23,7 +23,7 @@
 int string_get_size(u64 size, const enum string_size_units units,
                     char *buf, int len)
 {
-        const char *units_10[] = { "B", "KB", "MB", "GB", "TB", "PB",
+        const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
                                    "EB", "ZB", "YB", NULL};
         const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
                                  "EiB", "ZiB", "YiB", NULL };
@@ -31,7 +31,7 @@ int string_get_size(u64 size, const enum string_size_units units,
                 [STRING_UNITS_10] =  units_10,
                 [STRING_UNITS_2] = units_2,
         };
-        const int divisor[] = {
+        const unsigned int divisor[] = {
                 [STRING_UNITS_10] = 1000,
                 [STRING_UNITS_2] = 1024,
         };
@@ -40,23 +40,27 @@ int string_get_size(u64 size, const enum string_size_units units,
         char tmp[8];
 
         tmp[0] = '\0';
+        i = 0;
+        if (size >= divisor[units]) {
+                while (size >= divisor[units] && units_str[units][i]) {
+                        remainder = do_div(size, divisor[units]);
+                        i++;
+                }
 
-        for (i = 0; size > divisor[units] && units_str[units][i]; i++)
-                remainder = do_div(size, divisor[units]);
+                sf_cap = size;
+                for (j = 0; sf_cap*10 < 1000; j++)
+                        sf_cap *= 10;
 
-        sf_cap = size;
-        for (j = 0; sf_cap*10 < 1000; j++)
-                sf_cap *= 10;
-
-        if (j) {
-                remainder *= 1000;
-                do_div(remainder, divisor[units]);
-                snprintf(tmp, sizeof(tmp), ".%03lld",
-                         (unsigned long long)remainder);
-                tmp[j+1] = '\0';
+                if (j) {
+                        remainder *= 1000;
+                        do_div(remainder, divisor[units]);
+                        snprintf(tmp, sizeof(tmp), ".%03lld",
+                                 (unsigned long long)remainder);
+                        tmp[j+1] = '\0';
+                }
         }
 
-        snprintf(buf, len, "%lld%s%s", (unsigned long long)size,
+        snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
                  tmp, units_str[units][i]);
 
         return 0;