1 files changed, 5 insertions, 81 deletions

diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index 0374a596cffa..9aa0fccd5d43 100644
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -103,38 +103,14 @@ static inline void debug_spin_unlock(raw_spinlock_t *lock)
         lock->owner_cpu = -1;
 }
 
-static void __spin_lock_debug(raw_spinlock_t *lock)
-{
-        u64 i;
-        u64 loops = loops_per_jiffy * HZ;
-
-        for (i = 0; i < loops; i++) {
-                if (arch_spin_trylock(&lock->raw_lock))
-                        return;
-                __delay(1);
-        }
-        /* lockup suspected: */
-        spin_dump(lock, "lockup suspected");
-#ifdef CONFIG_SMP
-        trigger_all_cpu_backtrace();
-#endif
-
-        /*
-         * The trylock above was causing a livelock.  Give the lower level arch
-         * specific lock code a chance to acquire the lock. We have already
-         * printed a warning/backtrace at this point. The non-debug arch
-         * specific code might actually succeed in acquiring the lock.  If it is
-         * not successful, the end-result is the same - there is no forward
-         * progress.
-         */
-        arch_spin_lock(&lock->raw_lock);
-}
-
+/*
+ * We are now relying on the NMI watchdog to detect lockup instead of doing
+ * the detection here with an unfair lock which can cause problem of its own.
+ */
 void do_raw_spin_lock(raw_spinlock_t *lock)
 {
         debug_spin_lock_before(lock);
-        if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
-                __spin_lock_debug(lock);
+        arch_spin_lock(&lock->raw_lock);
         debug_spin_lock_after(lock);
 }
 
@@ -172,32 +148,6 @@ static void rwlock_bug(rwlock_t *lock, const char *msg)
 
 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
 
-#if 0           /* __write_lock_debug() can lock up - maybe this can too? */
-static void __read_lock_debug(rwlock_t *lock)
-{
-        u64 i;
-        u64 loops = loops_per_jiffy * HZ;
-        int print_once = 1;
-
-        for (;;) {
-                for (i = 0; i < loops; i++) {
-                        if (arch_read_trylock(&lock->raw_lock))
-                                return;
-                        __delay(1);
-                }
-                /* lockup suspected: */
-                if (print_once) {
-                        print_once = 0;
-                        printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
-                                        "%s/%d, %p\n",
-                                raw_smp_processor_id(), current->comm,
-                                current->pid, lock);
-                        dump_stack();
-                }
-        }
-}
-#endif
-
 void do_raw_read_lock(rwlock_t *lock)
 {
         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
@@ -247,32 +197,6 @@ static inline void debug_write_unlock(rwlock_t *lock)
         lock->owner_cpu = -1;
 }
 
-#if 0           /* This can cause lockups */
-static void __write_lock_debug(rwlock_t *lock)
-{
-        u64 i;
-        u64 loops = loops_per_jiffy * HZ;
-        int print_once = 1;
-
-        for (;;) {
-                for (i = 0; i < loops; i++) {
-                        if (arch_write_trylock(&lock->raw_lock))
-                                return;
-                        __delay(1);
-                }
-                /* lockup suspected: */
-                if (print_once) {
-                        print_once = 0;
-                        printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
-                                        "%s/%d, %p\n",
-                                raw_smp_processor_id(), current->comm,
-                                current->pid, lock);
-                        dump_stack();
-                }
-        }
-}
-#endif
-
 void do_raw_write_lock(rwlock_t *lock)
 {
         debug_write_lock_before(lock);