[PATCH] oneliner race fix for ldt updates

Problem: if another CPU is using lazy-TLB, the LDT flushing won't flush
the other CPU's LDT entry.

Fix: use active_mm instead of mm for the flush IPI.

arch/i386/kernel/ldt.c

@@ -20,10 +20,10 @@
 #include <asm/desc.h>
 
 #ifdef CONFIG_SMP /* avoids "defined but not used" warnig */
-static void flush_ldt(void *mm)
+static void flush_ldt(void *null)
 {
-	if (current->mm)
-		load_LDT(&current->mm->context);
+	if (current->active_mm)
+		load_LDT(&current->active_mm->context);
 }
 #endif