1 files changed, 102 insertions, 29 deletions

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 348b3a9170fa..6f09d13be6b6 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -8,6 +8,7 @@
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/uaccess.h>
+#include <linux/panic.h>
 #include <linux/slab.h>
 #include <linux/sync_file.h>
 
@@ -52,12 +53,33 @@ struct sw_sync_create_fence_data {
 	__s32	fence; /* fd of new fence */
 };
 
+/**
+ * struct sw_sync_get_deadline - get the deadline hint of a sw_sync fence
+ * @deadline_ns: absolute time of the deadline
+ * @pad:	must be zero
+ * @fence_fd:	the sw_sync fence fd (in)
+ *
+ * Return the earliest deadline set on the fence.  The timebase for the
+ * deadline is CLOCK_MONOTONIC (same as vblank).  If there is no deadline
+ * set on the fence, this ioctl will return -ENOENT.
+ */
+struct sw_sync_get_deadline {
+	__u64	deadline_ns;
+	__u32	pad;
+	__s32	fence_fd;
+};
+
 #define SW_SYNC_IOC_MAGIC	'W'
 
 #define SW_SYNC_IOC_CREATE_FENCE	_IOWR(SW_SYNC_IOC_MAGIC, 0,\
 		struct sw_sync_create_fence_data)
 
 #define SW_SYNC_IOC_INC			_IOW(SW_SYNC_IOC_MAGIC, 1, __u32)
+#define SW_SYNC_GET_DEADLINE		_IOWR(SW_SYNC_IOC_MAGIC, 2, \
+		struct sw_sync_get_deadline)
+
+
+#define SW_SYNC_HAS_DEADLINE_BIT	DMA_FENCE_FLAG_USER_BITS
 
 static const struct dma_fence_ops timeline_fence_ops;
 
@@ -85,7 +107,7 @@ static struct sync_timeline *sync_timeline_create(const char *name)
 
 	kref_init(&obj->kref);
 	obj->context = dma_fence_context_alloc(1);
-	strlcpy(obj->name, name, sizeof(obj->name));
+	strscpy(obj->name, name, sizeof(obj->name));
 
 	obj->pt_tree = RB_ROOT;
 	INIT_LIST_HEAD(&obj->pt_list);
@@ -149,36 +171,31 @@ static bool timeline_fence_signaled(struct dma_fence *fence)
 {
 	struct sync_timeline *parent = dma_fence_parent(fence);
 
-	return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops);
-}
-
-static bool timeline_fence_enable_signaling(struct dma_fence *fence)
-{
-	return true;
-}
-
-static void timeline_fence_value_str(struct dma_fence *fence,
-				    char *str, int size)
-{
-	snprintf(str, size, "%lld", fence->seqno);
+	return !__dma_fence_is_later(fence, fence->seqno, parent->value);
 }
 
-static void timeline_fence_timeline_value_str(struct dma_fence *fence,
-					     char *str, int size)
+static void timeline_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
 {
-	struct sync_timeline *parent = dma_fence_parent(fence);
+	struct sync_pt *pt = dma_fence_to_sync_pt(fence);
+	unsigned long flags;
 
-	snprintf(str, size, "%d", parent->value);
+	spin_lock_irqsave(fence->lock, flags);
+	if (test_bit(SW_SYNC_HAS_DEADLINE_BIT, &fence->flags)) {
+		if (ktime_before(deadline, pt->deadline))
+			pt->deadline = deadline;
+	} else {
+		pt->deadline = deadline;
+		__set_bit(SW_SYNC_HAS_DEADLINE_BIT, &fence->flags);
+	}
+	spin_unlock_irqrestore(fence->lock, flags);
 }
 
 static const struct dma_fence_ops timeline_fence_ops = {
 	.get_driver_name = timeline_fence_get_driver_name,
 	.get_timeline_name = timeline_fence_get_timeline_name,
-	.enable_signaling = timeline_fence_enable_signaling,
 	.signaled = timeline_fence_signaled,
 	.release = timeline_fence_release,
-	.fence_value_str = timeline_fence_value_str,
-	.timeline_value_str = timeline_fence_timeline_value_str,
+	.set_deadline = timeline_fence_set_deadline,
 };
 
 /**
@@ -191,6 +208,7 @@ static const struct dma_fence_ops timeline_fence_ops = {
  */
 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 {
+	LIST_HEAD(signalled);
 	struct sync_pt *pt, *next;
 
 	trace_sync_timeline(obj);
@@ -203,21 +221,20 @@ static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 		if (!timeline_fence_signaled(&pt->base))
 			break;
 
-		list_del_init(&pt->link);
+		dma_fence_get(&pt->base);
+
+		list_move_tail(&pt->link, &signalled);
 		rb_erase(&pt->node, &obj->pt_tree);
 
-		/*
-		 * A signal callback may release the last reference to this
-		 * fence, causing it to be freed. That operation has to be
-		 * last to avoid a use after free inside this loop, and must
-		 * be after we remove the fence from the timeline in order to
-		 * prevent deadlocking on timeline->lock inside
-		 * timeline_fence_release().
-		 */
 		dma_fence_signal_locked(&pt->base);
 	}
 
 	spin_unlock_irq(&obj->lock);
+
+	list_for_each_entry_safe(pt, next, &signalled, link) {
+		list_del_init(&pt->link);
+		dma_fence_put(&pt->base);
+	}
 }
 
 /**
@@ -333,6 +350,9 @@ static long sw_sync_ioctl_create_fence(struct sync_timeline *obj,
 	struct sync_file *sync_file;
 	struct sw_sync_create_fence_data data;
 
+	/* SW sync fence are inherently unsafe and can deadlock the kernel */
+	add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
+
 	if (fd < 0)
 		return fd;
 
@@ -387,6 +407,56 @@ static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg)
 	return 0;
 }
 
+static int sw_sync_ioctl_get_deadline(struct sync_timeline *obj, unsigned long arg)
+{
+	struct sw_sync_get_deadline data;
+	struct dma_fence *fence;
+	unsigned long flags;
+	struct sync_pt *pt;
+	int ret = 0;
+
+	if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
+		return -EFAULT;
+
+	if (data.deadline_ns || data.pad)
+		return -EINVAL;
+
+	fence = sync_file_get_fence(data.fence_fd);
+	if (!fence)
+		return -EINVAL;
+
+	pt = dma_fence_to_sync_pt(fence);
+	if (!pt) {
+		ret = -EINVAL;
+		goto put_fence;
+	}
+
+	spin_lock_irqsave(fence->lock, flags);
+	if (!test_bit(SW_SYNC_HAS_DEADLINE_BIT, &fence->flags)) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+	data.deadline_ns = ktime_to_ns(pt->deadline);
+	spin_unlock_irqrestore(fence->lock, flags);
+
+	dma_fence_put(fence);
+
+	if (ret)
+		return ret;
+
+	if (copy_to_user((void __user *)arg, &data, sizeof(data)))
+		return -EFAULT;
+
+	return 0;
+
+unlock:
+	spin_unlock_irqrestore(fence->lock, flags);
+put_fence:
+	dma_fence_put(fence);
+
+	return ret;
+}
+
 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
 			  unsigned long arg)
 {
@@ -399,6 +469,9 @@ static long sw_sync_ioctl(struct file *file, unsigned int cmd,
 	case SW_SYNC_IOC_INC:
 		return sw_sync_ioctl_inc(obj, arg);
 
+	case SW_SYNC_GET_DEADLINE:
+		return sw_sync_ioctl_get_deadline(obj, arg);
+
 	default:
 		return -ENOTTY;
 	}