Merge remote-tracking branch 'tip/auto-latest'

Conflicts:
	arch/arm64/include/asm/thread_info.h
	arch/arm64/mm/mmu.c
	drivers/block/mtip32xx/mtip32xx.c

3 files changed, 59 insertions, 8 deletions

diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 4f560cfedc8..51c4b24b632 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -54,9 +54,9 @@ enum {
  * table (if it's not there yet), and we check it for lock order
  * conflicts and deadlocks.
  */
-#define MAX_LOCKDEP_ENTRIES	16384UL
+#define MAX_LOCKDEP_ENTRIES	32768UL
 
-#define MAX_LOCKDEP_CHAINS_BITS	15
+#define MAX_LOCKDEP_CHAINS_BITS	16
 #define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
 
 #define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
@@ -65,7 +65,7 @@ enum {
  * Stack-trace: tightly packed array of stack backtrace
  * addresses. Protected by the hash_lock.
  */
-#define MAX_STACK_TRACE_ENTRIES	262144UL
+#define MAX_STACK_TRACE_ENTRIES	524288UL
 
 extern struct list_head all_lock_classes;
 extern struct lock_chain lock_chains[];
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a18e34..0955b885d0d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -82,14 +82,14 @@ struct lock_writer_stress_stats {
 };
 static struct lock_writer_stress_stats *lwsa;
 
-#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
+#if defined(MODULE)
 #define LOCKTORTURE_RUNNABLE_INIT 1
 #else
 #define LOCKTORTURE_RUNNABLE_INIT 0
 #endif
 int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
 module_param(locktorture_runnable, int, 0444);
-MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
+MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at module init");
 
 /* Forward reference. */
 static void lock_torture_cleanup(void);
@@ -216,10 +216,11 @@ static int lock_torture_writer(void *arg)
 	static DEFINE_TORTURE_RANDOM(rand);
 
 	VERBOSE_TOROUT_STRING("lock_torture_writer task started");
-	set_user_nice(current, 19);
+	set_user_nice(current, MAX_NICE);
 
 	do {
-		schedule_timeout_uninterruptible(1);
+		if ((torture_random(&rand) & 0xfffff) == 0)
+			schedule_timeout_uninterruptible(1);
 		cur_ops->writelock();
 		if (WARN_ON_ONCE(lock_is_write_held))
 			lwsp->n_write_lock_fail++;
@@ -354,7 +355,8 @@ static int __init lock_torture_init(void)
 		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
 	};
 
-	torture_init_begin(torture_type, verbose, &locktorture_runnable);
+	if (!torture_init_begin(torture_type, verbose, &locktorture_runnable))
+		return -EBUSY;
 
 	/* Process args and tell the world that the torturer is on the job. */
 	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 1d66e08e897..b4219ff87b8 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -12,6 +12,55 @@
 #include <linux/export.h>
 
 /*
+ * Guide to the rw_semaphore's count field for common values.
+ * (32-bit case illustrated, similar for 64-bit)
+ *
+ * 0x0000000X	(1) X readers active or attempting lock, no writer waiting
+ *		    X = #active_readers + #readers attempting to lock
+ *		    (X*ACTIVE_BIAS)
+ *
+ * 0x00000000	rwsem is unlocked, and no one is waiting for the lock or
+ *		attempting to read lock or write lock.
+ *
+ * 0xffff000X	(1) X readers active or attempting lock, with waiters for lock
+ *		    X = #active readers + # readers attempting lock
+ *		    (X*ACTIVE_BIAS + WAITING_BIAS)
+ *		(2) 1 writer attempting lock, no waiters for lock
+ *		    X-1 = #active readers + #readers attempting lock
+ *		    ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS)
+ *		(3) 1 writer active, no waiters for lock
+ *		    X-1 = #active readers + #readers attempting lock
+ *		    ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS)
+ *
+ * 0xffff0001	(1) 1 reader active or attempting lock, waiters for lock
+ *		    (WAITING_BIAS + ACTIVE_BIAS)
+ *		(2) 1 writer active or attempting lock, no waiters for lock
+ *		    (ACTIVE_WRITE_BIAS)
+ *
+ * 0xffff0000	(1) There are writers or readers queued but none active
+ *		    or in the process of attempting lock.
+ *		    (WAITING_BIAS)
+ *		Note: writer can attempt to steal lock for this count by adding
+ *		ACTIVE_WRITE_BIAS in cmpxchg and checking the old count
+ *
+ * 0xfffe0001	(1) 1 writer active, or attempting lock. Waiters on queue.
+ *		    (ACTIVE_WRITE_BIAS + WAITING_BIAS)
+ *
+ * Note: Readers attempt to lock by adding ACTIVE_BIAS in down_read and checking
+ *	 the count becomes more than 0 for successful lock acquisition,
+ *	 i.e. the case where there are only readers or nobody has lock.
+ *	 (1st and 2nd case above).
+ *
+ *	 Writers attempt to lock by adding ACTIVE_WRITE_BIAS in down_write and
+ *	 checking the count becomes ACTIVE_WRITE_BIAS for successful lock
+ *	 acquisition (i.e. nobody else has lock or attempts lock).  If
+ *	 unsuccessful, in rwsem_down_write_failed, we'll check to see if there
+ *	 are only waiters but none active (5th case above), and attempt to
+ *	 steal the lock.
+ *
+ */
+
+/*
  * Initialize an rwsem:
  */
 void __init_rwsem(struct rw_semaphore *sem, const char *name,