Merge "locking/spinlock/debug: Remove spinlock lockup detection code" (c021a2ce) · Commits · e / devices / android_kernel_fairphone_FP3

kernel/locking/spinlock_debug.c

+5 −81

Original line number	Diff line number	Diff line
		@@ -110,38 +110,14 @@ 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_bug(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.
		* 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.
		*/
		arch_spin_lock(&lock->raw_lock);
		}

		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);
		}

		@@ -184,32 +160,6 @@ 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");
		@@ -259,32 +209,6 @@ 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);