1 files changed, 110 insertions, 23 deletions

diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c
index ed6d5449741..f14581bd707 100644
--- a/drivers/media/video/uvc/uvc_queue.c
+++ b/drivers/media/video/uvc/uvc_queue.c
@@ -90,6 +90,39 @@ void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
 }
 
 /*
+ * Free the video buffers.
+ *
+ * This function must be called with the queue lock held.
+ */
+static int __uvc_free_buffers(struct uvc_video_queue *queue)
+{
+	unsigned int i;
+
+	for (i = 0; i < queue->count; ++i) {
+		if (queue->buffer[i].vma_use_count != 0)
+			return -EBUSY;
+	}
+
+	if (queue->count) {
+		vfree(queue->mem);
+		queue->count = 0;
+	}
+
+	return 0;
+}
+
+int uvc_free_buffers(struct uvc_video_queue *queue)
+{
+	int ret;
+
+	mutex_lock(&queue->mutex);
+	ret = __uvc_free_buffers(queue);
+	mutex_unlock(&queue->mutex);
+
+	return ret;
+}
+
+/*
  * Allocate the video buffers.
  *
  * Pages are reserved to make sure they will not be swapped, as they will be
@@ -110,7 +143,7 @@ int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers,
 
 	mutex_lock(&queue->mutex);
 
-	if ((ret = uvc_free_buffers(queue)) < 0)
+	if ((ret = __uvc_free_buffers(queue)) < 0)
 		goto done;
 
 	/* Bail out if no buffers should be allocated. */
@@ -152,28 +185,6 @@ done:
 }
 
 /*
- * Free the video buffers.
- *
- * This function must be called with the queue lock held.
- */
-int uvc_free_buffers(struct uvc_video_queue *queue)
-{
-	unsigned int i;
-
-	for (i = 0; i < queue->count; ++i) {
-		if (queue->buffer[i].vma_use_count != 0)
-			return -EBUSY;
-	}
-
-	if (queue->count) {
-		vfree(queue->mem);
-		queue->count = 0;
-	}
-
-	return 0;
-}
-
-/*
  * Check if buffers have been allocated.
  */
 int uvc_queue_allocated(struct uvc_video_queue *queue)
@@ -369,6 +380,82 @@ done:
 }
 
 /*
+ * VMA operations.
+ */
+static void uvc_vm_open(struct vm_area_struct *vma)
+{
+	struct uvc_buffer *buffer = vma->vm_private_data;
+	buffer->vma_use_count++;
+}
+
+static void uvc_vm_close(struct vm_area_struct *vma)
+{
+	struct uvc_buffer *buffer = vma->vm_private_data;
+	buffer->vma_use_count--;
+}
+
+static const struct vm_operations_struct uvc_vm_ops = {
+	.open		= uvc_vm_open,
+	.close		= uvc_vm_close,
+};
+
+/*
+ * Memory-map a video buffer.
+ *
+ * This function implements video buffers memory mapping and is intended to be
+ * used by the device mmap handler.
+ */
+int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
+{
+	struct uvc_buffer *uninitialized_var(buffer);
+	struct page *page;
+	unsigned long addr, start, size;
+	unsigned int i;
+	int ret = 0;
+
+	start = vma->vm_start;
+	size = vma->vm_end - vma->vm_start;
+
+	mutex_lock(&queue->mutex);
+
+	for (i = 0; i < queue->count; ++i) {
+		buffer = &queue->buffer[i];
+		if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff)
+			break;
+	}
+
+	if (i == queue->count || size != queue->buf_size) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	/*
+	 * VM_IO marks the area as being an mmaped region for I/O to a
+	 * device. It also prevents the region from being core dumped.
+	 */
+	vma->vm_flags |= VM_IO;
+
+	addr = (unsigned long)queue->mem + buffer->buf.m.offset;
+	while (size > 0) {
+		page = vmalloc_to_page((void *)addr);
+		if ((ret = vm_insert_page(vma, start, page)) < 0)
+			goto done;
+
+		start += PAGE_SIZE;
+		addr += PAGE_SIZE;
+		size -= PAGE_SIZE;
+	}
+
+	vma->vm_ops = &uvc_vm_ops;
+	vma->vm_private_data = buffer;
+	uvc_vm_open(vma);
+
+done:
+	mutex_unlock(&queue->mutex);
+	return ret;
+}
+
+/*
  * Poll the video queue.
  *
  * This function implements video queue polling and is intended to be used by