xen/console: debugtrace: Compute the buffer length is O(1) rather O(n)

This was meant to be part of commit e0bf98394e "xen/console: Fix build
when CONFIG_DEBUG_TRACE" but not addressed before been committed.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 75e493466ea4dc8c189d277fe24098b02637278d..d67e1993f20a5ba4ff96b56c1d6ed836a548abc3 100644 (file)
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -1187,7 +1187,7 @@ static void debugtrace_dump_worker(void)
     ASSERT(debugtrace_buf[debugtrace_bytes - 1] == 0);
     if ( debugtrace_buf[debugtrace_prd] != '\0' )
         sercon_puts(&debugtrace_buf[debugtrace_prd],
-                    strlen(&debugtrace_buf[debugtrace_prd]));
+                    debugtrace_bytes - debugtrace_prd - 1);
 
     /* Print youngest portion of the ring. */
     debugtrace_buf[debugtrace_prd] = '\0';