1 files changed, 46 insertions, 20 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 25fc3841a2b1..5c45e9e598de 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1772,13 +1772,18 @@ static int i915_pipe_crc_open(struct inode *inode, struct file *filep)
 	struct drm_i915_private *dev_priv = info->dev->dev_private;
 	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
 
-	if (!atomic_dec_and_test(&pipe_crc->available)) {
-		atomic_inc(&pipe_crc->available);
+	spin_lock_irq(&pipe_crc->lock);
+
+	if (pipe_crc->opened) {
+		spin_unlock_irq(&pipe_crc->lock);
 		return -EBUSY; /* already open */
 	}
 
+	pipe_crc->opened = true;
 	filep->private_data = inode->i_private;
 
+	spin_unlock_irq(&pipe_crc->lock);
+
 	return 0;
 }
 
@@ -1788,7 +1793,9 @@ static int i915_pipe_crc_release(struct inode *inode, struct file *filep)
 	struct drm_i915_private *dev_priv = info->dev->dev_private;
 	struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[info->pipe];
 
-	atomic_inc(&pipe_crc->available); /* release the device */
+	spin_lock_irq(&pipe_crc->lock);
+	pipe_crc->opened = false;
+	spin_unlock_irq(&pipe_crc->lock);
 
 	return 0;
 }
@@ -1800,12 +1807,9 @@ static int i915_pipe_crc_release(struct inode *inode, struct file *filep)
 
 static int pipe_crc_data_count(struct intel_pipe_crc *pipe_crc)
 {
-	int head, tail;
-
-	head = atomic_read(&pipe_crc->head);
-	tail = atomic_read(&pipe_crc->tail);
-
-	return CIRC_CNT(head, tail, INTEL_PIPE_CRC_ENTRIES_NR);
+	assert_spin_locked(&pipe_crc->lock);
+	return CIRC_CNT(pipe_crc->head, pipe_crc->tail,
+			INTEL_PIPE_CRC_ENTRIES_NR);
 }
 
 static ssize_t
@@ -1831,20 +1835,30 @@ i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
 		return 0;
 
 	/* nothing to read */
+	spin_lock_irq(&pipe_crc->lock);
 	while (pipe_crc_data_count(pipe_crc) == 0) {
-		if (filep->f_flags & O_NONBLOCK)
+		int ret;
+
+		if (filep->f_flags & O_NONBLOCK) {
+			spin_unlock_irq(&pipe_crc->lock);
 			return -EAGAIN;
+		}
 
-		if (wait_event_interruptible(pipe_crc->wq,
-					     pipe_crc_data_count(pipe_crc)))
-			 return -ERESTARTSYS;
+		ret = wait_event_interruptible_lock_irq(pipe_crc->wq,
+				pipe_crc_data_count(pipe_crc), pipe_crc->lock);
+		if (ret) {
+			spin_unlock_irq(&pipe_crc->lock);
+			return ret;
+		}
 	}
 
 	/* We now have one or more entries to read */
-	head = atomic_read(&pipe_crc->head);
-	tail = atomic_read(&pipe_crc->tail);
+	head = pipe_crc->head;
+	tail = pipe_crc->tail;
 	n_entries = min((size_t)CIRC_CNT(head, tail, INTEL_PIPE_CRC_ENTRIES_NR),
 			count / PIPE_CRC_LINE_LEN);
+	spin_unlock_irq(&pipe_crc->lock);
+
 	bytes_read = 0;
 	n = 0;
 	do {
@@ -1864,10 +1878,13 @@ i915_pipe_crc_read(struct file *filep, char __user *user_buf, size_t count,
 
 		BUILD_BUG_ON_NOT_POWER_OF_2(INTEL_PIPE_CRC_ENTRIES_NR);
 		tail = (tail + 1) & (INTEL_PIPE_CRC_ENTRIES_NR - 1);
-		atomic_set(&pipe_crc->tail, tail);
 		n++;
 	} while (--n_entries);
 
+	spin_lock_irq(&pipe_crc->lock);
+	pipe_crc->tail = tail;
+	spin_unlock_irq(&pipe_crc->lock);
+
 	return bytes_read;
 }
 
@@ -2111,8 +2128,10 @@ static int pipe_crc_set_source(struct drm_device *dev, enum pipe pipe,
 		if (!pipe_crc->entries)
 			return -ENOMEM;
 
-		atomic_set(&pipe_crc->head, 0);
-		atomic_set(&pipe_crc->tail, 0);
+		spin_lock_irq(&pipe_crc->lock);
+		pipe_crc->head = 0;
+		pipe_crc->tail = 0;
+		spin_unlock_irq(&pipe_crc->lock);
 	}
 
 	pipe_crc->source = source;
@@ -2122,13 +2141,19 @@ static int pipe_crc_set_source(struct drm_device *dev, enum pipe pipe,
 
 	/* real source -> none transition */
 	if (source == INTEL_PIPE_CRC_SOURCE_NONE) {
+		struct intel_pipe_crc_entry *entries;
+
 		DRM_DEBUG_DRIVER("stopping CRCs for pipe %c\n",
 				 pipe_name(pipe));
 
 		intel_wait_for_vblank(dev, pipe);
 
-		kfree(pipe_crc->entries);
+		spin_lock_irq(&pipe_crc->lock);
+		entries = pipe_crc->entries;
 		pipe_crc->entries = NULL;
+		spin_unlock_irq(&pipe_crc->lock);
+
+		kfree(entries);
 	}
 
 	return 0;
@@ -2823,7 +2848,8 @@ void intel_display_crc_init(struct drm_device *dev)
 	for (i = 0; i < INTEL_INFO(dev)->num_pipes; i++) {
 		struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[i];
 
-		atomic_set(&pipe_crc->available, 1);
+		pipe_crc->opened = false;
+		spin_lock_init(&pipe_crc->lock);
 		init_waitqueue_head(&pipe_crc->wq);
 	}
 }