x86: convert mm_context_t semaphore to a mutex

convert mm_context_t semaphore to a mutex.

Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index d84314c..6555c3d 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -105,7 +105,7 @@
 	   LDT and other horrors are only used in user space. */
 	if (seg & (1<<2)) {
 		/* Must lock the LDT while reading it. */
-		down(&current->mm->context.sem);
+		mutex_lock(&current->mm->context.lock);
 		desc = current->mm->context.ldt;
 		desc = (void *)desc + (seg & ~7);
 	} else {
@@ -118,7 +118,7 @@
 	base = get_desc_base((unsigned long *)desc);
 
 	if (seg & (1<<2)) { 
-		up(&current->mm->context.sem);
+		mutex_unlock(&current->mm->context.lock);
 	} else
 		put_cpu();