Merge branch 'linus' into perf/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 45 insertions, 5 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 8153fdab287f..90dc5520b784 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -23,7 +23,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
          sha1.o chacha20.o irq_regs.o argv_split.o \
          flex_proportions.o ratelimit.o show_mem.o \
          is_single_threaded.o plist.o decompress.o kobject_uevent.o \
-         earlycpio.o seq_buf.o siphash.o \
+         earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
          nmi_backtrace.o nodemask.o win_minmax.o
 
 lib-$(CONFIG_PRINTK) += dump_stack.o
@@ -95,10 +95,6 @@ obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
 obj-$(CONFIG_DEBUG_LIST) += list_debug.o
 obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
 
-ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
-  lib-y += dec_and_lock.o
-endif
-
 obj-$(CONFIG_BITREVERSE) += bitrev.o
 obj-$(CONFIG_RATIONAL)  += rational.o
 obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o
diff --git a/lib/dec_and_lock.c b/lib/dec_and_lock.c
index 347fa7ac2e8a..9555b68bb774 100644
--- a/lib/dec_and_lock.c
+++ b/lib/dec_and_lock.c
@@ -33,3 +33,19 @@ int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
 }
 
 EXPORT_SYMBOL(_atomic_dec_and_lock);
+
+int _atomic_dec_and_lock_irqsave(atomic_t *atomic, spinlock_t *lock,
+                                 unsigned long *flags)
+{
+        /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
+        if (atomic_add_unless(atomic, -1, 1))
+                return 0;
+
+        /* Otherwise do it the slow way */
+        spin_lock_irqsave(lock, *flags);
+        if (atomic_dec_and_test(atomic))
+                return 1;
+        spin_unlock_irqrestore(lock, *flags);
+        return 0;
+}
+EXPORT_SYMBOL(_atomic_dec_and_lock_irqsave);
diff --git a/lib/refcount.c b/lib/refcount.c
index 0eb48353abe3..d3b81cefce91 100644
--- a/lib/refcount.c
+++ b/lib/refcount.c
@@ -350,3 +350,31 @@ bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock)
 }
 EXPORT_SYMBOL(refcount_dec_and_lock);
 
+/**
+ * refcount_dec_and_lock_irqsave - return holding spinlock with disabled
+ *                                 interrupts if able to decrement refcount to 0
+ * @r: the refcount
+ * @lock: the spinlock to be locked
+ * @flags: saved IRQ-flags if the is acquired
+ *
+ * Same as refcount_dec_and_lock() above except that the spinlock is acquired
+ * with disabled interupts.
+ *
+ * Return: true and hold spinlock if able to decrement refcount to 0, false
+ *         otherwise
+ */
+bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock,
+                                   unsigned long *flags)
+{
+        if (refcount_dec_not_one(r))
+                return false;
+
+        spin_lock_irqsave(lock, *flags);
+        if (!refcount_dec_and_test(r)) {
+                spin_unlock_irqrestore(lock, *flags);
+                return false;
+        }
+
+        return true;
+}
+EXPORT_SYMBOL(refcount_dec_and_lock_irqsave);