upstream: [media] vb2: Improve file I/O emulation to handle buffers in any order

videobuf2 file I/O emulation assumed that buffers dequeued from the
driver would return in the order they were enqueued in the driver.

Improve the file I/O emulator's book-keeping to remove this assumption.

Also set the buf->size properly if a write() dequeues a buffer and the
VB2_FILEIO_WRITE_IMMEDIATELY flag is set.

Based on an initial patch by Andy Walls.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index b79808a..60407de 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -2366,6 +2366,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
                                goto err_reqbufs;
                        fileio->bufs[i].queued = 1;
                }
+               fileio->index = q->num_buffers;
        }
 
        /*
@@ -2441,15 +2442,11 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
        }
        fileio = q->fileio;
 
-       index = fileio->index;
-       buf = &fileio->bufs[index];
-
        /*
         * Check if we need to dequeue the buffer.
         */
-       if (buf->queued) {
-               struct vb2_buffer *vb;
-
+       index = fileio->index;
+       if (index >= q->num_buffers) {
                /*
                 * Call vb2_dqbuf to get buffer back.
                 */
@@ -2462,12 +2459,18 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
                        return ret;
                fileio->dq_count += 1;
 
+               index = fileio->b.index;
+               buf = &fileio->bufs[index];
+
                /*
                 * Get number of bytes filled by the driver
                 */
-               vb = q->bufs[index];
-               buf->size = vb2_get_plane_payload(vb, 0);
+               buf->pos = 0;
                buf->queued = 0;
+               buf->size = read ? vb2_get_plane_payload(q->bufs[index], 0)
+                                : vb2_plane_size(q->bufs[index], 0);
+       } else {
+               buf = &fileio->bufs[index];
        }
 
        /*
@@ -2530,13 +2533,10 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
                 */
                buf->pos = 0;
                buf->queued = 1;
-               buf->size = q->bufs[0]->v4l2_planes[0].length;
+               buf->size = vb2_plane_size(q->bufs[index], 0);
                fileio->q_count += 1;
-
-               /*
-                * Switch to the next buffer
-                */
-               fileio->index = (index + 1) % q->num_buffers;
+               if (fileio->index < q->num_buffers)
+                       fileio->index++;
        }
 
        /*