1 files changed, 27 insertions, 29 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5801a14f7524..66dd3fe99b82 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -357,34 +357,24 @@ void x86_release_hardware(void)
  */
 int x86_add_exclusive(unsigned int what)
 {
-	int ret = -EBUSY, i;
-
-	if (atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what]))
-		return 0;
+	int i;
 
-	mutex_lock(&pmc_reserve_mutex);
-	for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++) {
-		if (i != what && atomic_read(&x86_pmu.lbr_exclusive[i]))
-			goto out;
+	if (!atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what])) {
+		mutex_lock(&pmc_reserve_mutex);
+		for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++) {
+			if (i != what && atomic_read(&x86_pmu.lbr_exclusive[i]))
+				goto fail_unlock;
+		}
+		atomic_inc(&x86_pmu.lbr_exclusive[what]);
+		mutex_unlock(&pmc_reserve_mutex);
 	}
 
-	atomic_inc(&x86_pmu.lbr_exclusive[what]);
-	ret = 0;
+	atomic_inc(&active_events);
+	return 0;
 
-out:
+fail_unlock:
 	mutex_unlock(&pmc_reserve_mutex);
-
-	/*
-	 * Assuming that all exclusive events will share the PMI handler
-	 * (which checks active_events for whether there is work to do),
-	 * we can bump active_events counter right here, except for
-	 * x86_lbr_exclusive_lbr events that go through x86_pmu_event_init()
-	 * path, which already bumps active_events for them.
-	 */
-	if (!ret && what != x86_lbr_exclusive_lbr)
-		atomic_inc(&active_events);
-
-	return ret;
+	return -EBUSY;
 }
 
 void x86_del_exclusive(unsigned int what)
@@ -1561,7 +1551,7 @@ static void __init filter_events(struct attribute **attrs)
 }
 
 /* Merge two pointer arrays */
-static __init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
+__init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
 {
 	struct attribute **new;
 	int j, i;
@@ -2189,24 +2179,32 @@ static unsigned long get_segment_base(unsigned int segment)
 	int idx = segment >> 3;
 
 	if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) {
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+		struct ldt_struct *ldt;
+
 		if (idx > LDT_ENTRIES)
 			return 0;
 
-		if (idx > current->active_mm->context.size)
+		/* IRQs are off, so this synchronizes with smp_store_release */
+		ldt = lockless_dereference(current->active_mm->context.ldt);
+		if (!ldt || idx > ldt->size)
 			return 0;
 
-		desc = current->active_mm->context.ldt;
+		desc = &ldt->entries[idx];
+#else
+		return 0;
+#endif
 	} else {
 		if (idx > GDT_ENTRIES)
 			return 0;
 
-		desc = raw_cpu_ptr(gdt_page.gdt);
+		desc = raw_cpu_ptr(gdt_page.gdt) + idx;
 	}
 
-	return get_desc_base(desc + idx);
+	return get_desc_base(desc);
 }
 
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_IA32_EMULATION
 
 #include <asm/compat.h>