[media] media: vb2: fix handling MAPPED buffer flag

MAPPED flag was set for the buffer only if all it's planes were mapped and
relied on a simple mapping counter. This assumption is really bogus,
especially because the buffers may be mapped multiple times. Also the
meaning of this flag for muliplane buffers was not really useful. This
patch fixes this issue by setting the MAPPED flag for the buffer if any of
it's planes is in use (what means that has been mapped at least once), so
MAPPED flag can be used as 'in_use' indicator.

Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf2-core.c

@@ -276,6 +276,41 @@ static int __verify_planes_array(struct vb2_buffer *vb, struct v4l2_buffer *b)
 	return 0;
 }
 
+/**
+ * __buffer_in_use() - return true if the buffer is in use and
+ * the queue cannot be freed (by the means of REQBUFS(0)) call
+ */
+static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
+{
+	unsigned int plane;
+	for (plane = 0; plane < vb->num_planes; ++plane) {
+		/*
+		 * If num_users() has not been provided, call_memop
+		 * will return 0, apparently nobody cares about this
+		 * case anyway. If num_users() returns more than 1,
+		 * we are not the only user of the plane's memory.
+		 */
+		if (call_memop(q, plane, num_users,
+				vb->planes[plane].mem_priv) > 1)
+			return true;
+	}
+	return false;
+}
+
+/**
+ * __buffers_in_use() - return true if any buffers on the queue are in use and
+ * the queue cannot be freed (by the means of REQBUFS(0)) call
+ */
+static bool __buffers_in_use(struct vb2_queue *q)
+{
+	unsigned int buffer;
+	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+		if (__buffer_in_use(q, q->bufs[buffer]))
+			return true;
+	}
+	return false;
+}
+
 /**
  * __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
  * returned to userspace
@@ -335,7 +370,7 @@ static int __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
 		break;
 	}
 
-	if (vb->num_planes_mapped == vb->num_planes)
+	if (__buffer_in_use(q, vb))
 		b->flags |= V4L2_BUF_FLAG_MAPPED;
 
 	return ret;
@@ -399,33 +434,6 @@ static int __verify_mmap_ops(struct vb2_queue *q)
 	return 0;
 }
 
-/**
- * __buffers_in_use() - return true if any buffers on the queue are in use and
- * the queue cannot be freed (by the means of REQBUFS(0)) call
- */
-static bool __buffers_in_use(struct vb2_queue *q)
-{
-	unsigned int buffer, plane;
-	struct vb2_buffer *vb;
-
-	for (buffer = 0; buffer < q->num_buffers; ++buffer) {
-		vb = q->bufs[buffer];
-		for (plane = 0; plane < vb->num_planes; ++plane) {
-			/*
-			 * If num_users() has not been provided, call_memop
-			 * will return 0, apparently nobody cares about this
-			 * case anyway. If num_users() returns more than 1,
-			 * we are not the only user of the plane's memory.
-			 */
-			if (call_memop(q, plane, num_users,
-					vb->planes[plane].mem_priv) > 1)
-				return true;
-		}
-	}
-
-	return false;
-}
-
 /**
  * vb2_reqbufs() - Initiate streaming
  * @q:		videobuf2 queue
@@ -1343,9 +1351,6 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 	if (ret)
 		return ret;
 
-	vb_plane->mapped = 1;
-	vb->num_planes_mapped++;
-
 	dprintk(3, "Buffer %d, plane %d successfully mapped\n", buffer, plane);
 	return 0;
 }

include/media/videobuf2-core.h

@@ -75,7 +75,6 @@ struct vb2_mem_ops {
 
 struct vb2_plane {
 	void			*mem_priv;
-	int			mapped:1;
 };
 
 /**
@@ -147,7 +146,6 @@ struct vb2_queue;
  * @done_entry:		entry on the list that stores all buffers ready to
  *			be dequeued to userspace
  * @planes:		private per-plane information; do not change
- * @num_planes_mapped:	number of mapped planes; do not change
  */
 struct vb2_buffer {
 	struct v4l2_buffer	v4l2_buf;
@@ -164,7 +162,6 @@ struct vb2_buffer {
 	struct list_head	done_entry;
 
 	struct vb2_plane	planes[VIDEO_MAX_PLANES];
-	unsigned int		num_planes_mapped;
 };
 
 /**