[PATCH URGENT] common/vsprintf: Fix signed->unsigned error, causing glacial performance.

[Andrew Cooper <andrew.cooper3@citrix.com>]

The original patch for

  c/s 67a3542c5bc356e6452d8305991617c875f87de4
  "common/vsprintf: Refactor string() out of vsnprintf()"

specifically used signed integers, identical to the code copied out of vsprintf.

When committed, these had changed to unsigned integers, which causes a
functional change.  This causes glacial boot performance and an excessive
quantity of spaces printed to the serial console, as we loop to the upper
bound of a 32bit integer.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <JBeulich@suse.com>
---
 xen/common/vsprintf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/common/vsprintf.c b/xen/common/vsprintf.c
index e8f45eb..43dc392 100644
--- a/xen/common/vsprintf.c
+++ b/xen/common/vsprintf.c
@@ -239,7 +239,7 @@ static char *number(
 static char *string(char *str, char *end, const char *s,
                     int field_width, int precision, int flags)
 {
-    unsigned int i, len = strnlen(s, precision);
+    int i, len = strnlen(s, precision);
 
     if (!(flags & LEFT)) {
         while (len < field_width--) {
-- 
1.7.10.4