3 files changed, 82 insertions, 1 deletions

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
new file mode 100644
index 000000000000..a3eb2f65b656
--- /dev/null
+++ b/include/linux/string_helpers.h
@@ -0,0 +1,16 @@
+#ifndef _LINUX_STRING_HELPERS_H_
+#define _LINUX_STRING_HELPERS_H_
+
+#include <linux/types.h>
+
+/* Descriptions of the types of units to
+ * print in */
+enum string_size_units {
+        STRING_UNITS_10,        /* use powers of 10^3 (standard SI) */
+        STRING_UNITS_2,         /* use binary powers of 2^10 */
+};
+
+int string_get_size(u64 size, enum string_size_units units,
+                    char *buf, int len);
+
+#endif
diff --git a/lib/Makefile b/lib/Makefile
index 3b1f94bbe9de..44001af76a7d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -19,7 +19,8 @@ lib-$(CONFIG_SMP) += cpumask.o
 lib-y   += kobject.o kref.o klist.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
-         bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o
+         bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
+         string_helpers.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
new file mode 100644
index 000000000000..8347925030ff
--- /dev/null
+++ b/lib/string_helpers.c
@@ -0,0 +1,64 @@
+/*
+ * Helpers for formatting and printing strings
+ *
+ * Copyright 31 August 2008 James Bottomley
+ */
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/string_helpers.h>
+
+/**
+ * string_get_size - get the size in the specified units
+ * @size:       The size to be converted
+ * @units:      units to use (powers of 1000 or 1024)
+ * @buf:        buffer to format to
+ * @len:        length of buffer
+ *
+ * This function returns a string formatted to 3 significant figures
+ * giving the size in the required units.  Returns 0 on success or
+ * error on failure.  @buf is always zero terminated.
+ *
+ */
+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",
+                                   "EB", "ZB", "YB", NULL};
+        const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
+                                 "EiB", "ZiB", "YiB", NULL };
+        const char **units_str[] = {
+                [STRING_UNITS_10] =  units_10,
+                [STRING_UNITS_2] = units_2,
+        };
+        const int divisor[] = {
+                [STRING_UNITS_10] = 1000,
+                [STRING_UNITS_2] = 1024,
+        };
+        int i, j;
+        u64 remainder = 0, sf_cap;
+        char tmp[8];
+
+        tmp[0] = '\0';
+
+        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;
+
+        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,
+                 tmp, units_str[units][i]);
+
+        return 0;
+}
+EXPORT_SYMBOL(string_get_size);