Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core locking updates from Ingo Molnar:
 "The main changes in this cycle are:

   - Another attempt at enabling cross-release lockdep dependency
     tracking (automatically part of CONFIG_PROVE_LOCKING=y), this time
     with better performance and fewer false positives. (Byungchul Park)

   - Introduce lockdep_assert_irqs_enabled()/disabled() and convert
     open-coded equivalents to lockdep variants. (Frederic Weisbecker)

   - Add down_read_killable() and use it in the VFS's iterate_dir()
     method. (Kirill Tkhai)

   - Convert remaining uses of ACCESS_ONCE() to
     READ_ONCE()/WRITE_ONCE(). Most of the conversion was Coccinelle
     driven. (Mark Rutland, Paul E. McKenney)

   - Get rid of lockless_dereference(), by strengthening Alpha atomics,
     strengthening READ_ONCE() with smp_read_barrier_depends() and thus
     being able to convert users of lockless_dereference() to
     READ_ONCE(). (Will Deacon)

   - Various micro-optimizations:

        - better PV qspinlocks (Waiman Long),
        - better x86 barriers (Michael S. Tsirkin)
        - better x86 refcounts (Kees Cook)

   - ... plus other fixes and enhancements. (Borislav Petkov, Juergen
     Gross, Miguel Bernal Marin)"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  locking/x86: Use LOCK ADD for smp_mb() instead of MFENCE
  rcu: Use lockdep to assert IRQs are disabled/enabled
  netpoll: Use lockdep to assert IRQs are disabled/enabled
  timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled
  sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled
  irq_work: Use lockdep to assert IRQs are disabled/enabled
  irq/timings: Use lockdep to assert IRQs are disabled/enabled
  perf/core: Use lockdep to assert IRQs are disabled/enabled
  x86: Use lockdep to assert IRQs are disabled/enabled
  smp/core: Use lockdep to assert IRQs are disabled/enabled
  timers/hrtimer: Use lockdep to assert IRQs are disabled/enabled
  timers/nohz: Use lockdep to assert IRQs are disabled/enabled
  workqueue: Use lockdep to assert IRQs are disabled/enabled
  irq/softirqs: Use lockdep to assert IRQs are disabled/enabled
  locking/lockdep: Add IRQs disabled/enabled assertion APIs: lockdep_assert_irqs_enabled()/disabled()
  locking/pvqspinlock: Implement hybrid PV queued/unfair locks
  locking/rwlocks: Fix comments
  x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized
  block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion()
  workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes
  ...

5 files changed, 21 insertions, 8 deletions

diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c
index 9c4e7ba6870c..7d7715dde901 100644
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -155,14 +155,14 @@ void init_espfix_ap(int cpu)
 	page = cpu/ESPFIX_STACKS_PER_PAGE;
 
 	/* Did another CPU already set this up? */
-	stack_page = ACCESS_ONCE(espfix_pages[page]);
+	stack_page = READ_ONCE(espfix_pages[page]);
 	if (likely(stack_page))
 		goto done;
 
 	mutex_lock(&espfix_init_mutex);
 
 	/* Did we race on the lock? */
-	stack_page = ACCESS_ONCE(espfix_pages[page]);
+	stack_page = READ_ONCE(espfix_pages[page]);
 	if (stack_page)
 		goto unlock_done;
 
@@ -200,7 +200,7 @@ void init_espfix_ap(int cpu)
 		set_pte(&pte_p[n*PTE_STRIDE], pte);
 
 	/* Job is done for this CPU and any CPU which shares this page */
-	ACCESS_ONCE(espfix_pages[page]) = stack_page;
+	WRITE_ONCE(espfix_pages[page], stack_page);
 
 unlock_done:
 	mutex_unlock(&espfix_init_mutex);
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 4d17bacf4030..a2fcf037bd80 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -102,7 +102,7 @@ static void finalize_ldt_struct(struct ldt_struct *ldt)
 static void install_ldt(struct mm_struct *current_mm,
 			struct ldt_struct *ldt)
 {
-	/* Synchronizes with lockless_dereference in load_mm_ldt. */
+	/* Synchronizes with READ_ONCE in load_mm_ldt. */
 	smp_store_release(&current_mm->context.ldt, ldt);
 
 	/* Activate the LDT for all CPUs using current_mm. */
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 35aafc95e4b8..18bc9b51ac9b 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -105,7 +105,7 @@ static void nmi_max_handler(struct irq_work *w)
 {
 	struct nmiaction *a = container_of(w, struct nmiaction, irq_work);
 	int remainder_ns, decimal_msecs;
-	u64 whole_msecs = ACCESS_ONCE(a->max_duration);
+	u64 whole_msecs = READ_ONCE(a->max_duration);
 
 	remainder_ns = do_div(whole_msecs, (1000 * 1000));
 	decimal_msecs = remainder_ns / 1000;
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 19a3e8f961c7..041096bdef86 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -115,8 +115,18 @@ unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
 	return 5;
 }
 
-/* Neat trick to map patch type back to the call within the
- * corresponding structure. */
+DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
+
+void __init native_pv_lock_init(void)
+{
+	if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
+		static_branch_disable(&virt_spin_lock_key);
+}
+
+/*
+ * Neat trick to map patch type back to the call within the
+ * corresponding structure.
+ */
 static void *get_call_destination(u8 type)
 {
 	struct paravirt_patch_template tmpl = {
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 65a0ccdc3050..7ab6db86b573 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -77,6 +77,7 @@
 #include <asm/i8259.h>
 #include <asm/realmode.h>
 #include <asm/misc.h>
+#include <asm/qspinlock.h>
 
 /* Number of siblings per CPU package */
 int smp_num_siblings = 1;
@@ -1095,7 +1096,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
 	unsigned long flags;
 	int err, ret = 0;
 
-	WARN_ON(irqs_disabled());
+	lockdep_assert_irqs_enabled();
 
 	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
 
@@ -1358,6 +1359,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
 	pr_info("CPU0: ");
 	print_cpu_info(&cpu_data(0));
 
+	native_pv_lock_init();
+
 	uv_system_init();
 
 	set_mtrr_aps_delayed_init();