Merge tag 'ib-fbdev-drm-v4.19-deferred-console-takeover' of https://github.com/bzolnier/linux into drm-misc-next

Immutable branch between fbdev and drm for the v4.19 merge window
(contains the deferred console takeover feature)

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>

# gpg: Signature made Thu 28 Jun 2018 10:24:50 AM -03
# gpg:                using RSA key 7E33B63FA047C20B
# gpg: Can't check signature: public key not found

# Conflicts:
#	drivers/gpu/drm/i915/i915_gem.c
#	drivers/gpu/drm/i915/intel_crt.c
#	drivers/gpu/drm/i915/intel_display.c
#	drivers/gpu/drm/i915/intel_lrc.c
Link: https://patchwork.freedesktop.org/patch/msgid/2462549.rLSfW9kX99@amdc3058

1 files changed, 28 insertions, 0 deletions

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);