upstream: [media] vb2: don't init the list if there are still buffers

__vb2_queue_free() would init the queued_list at all times, even if
q->num_buffers > 0. This should only happen if num_buffers == 0.

This situation can happen if a CREATE_BUFFERS call couldn't allocate
enough buffers and had to free those it did manage to allocate before
returning an error.

While we're at it: __vb2_queue_alloc() returns the number of buffers
allocated, not an error code. So stick the result in allocated_buffers
instead of ret as that's very confusing.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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 98422f1..36fa510 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -456,9 +456,10 @@ static int __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
        }
 
        q->num_buffers -= buffers;
-       if (!q->num_buffers)
+       if (!q->num_buffers) {
                q->memory = 0;
-       INIT_LIST_HEAD(&q->queued_list);
+               INIT_LIST_HEAD(&q->queued_list);
+       }
        return 0;
 }
 
@@ -824,14 +825,12 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
        }
 
        /* Finally, allocate buffers and video memory */
-       ret = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes);
-       if (ret == 0) {
+       allocated_buffers = __vb2_queue_alloc(q, req->memory, num_buffers, num_planes);
+       if (allocated_buffers == 0) {
                dprintk(1, "Memory allocation failed\n");
                return -ENOMEM;
        }
 
-       allocated_buffers = ret;
-
        /*
         * Check if driver can handle the allocated number of buffers.
         */
@@ -855,6 +854,10 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
        q->num_buffers = allocated_buffers;
 
        if (ret < 0) {
+               /*
+                * Note: __vb2_queue_free() will subtract 'allocated_buffers'
+                * from q->num_buffers.
+                */
                __vb2_queue_free(q, allocated_buffers);
                return ret;
        }
@@ -930,20 +933,18 @@ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create
        }
 
        /* Finally, allocate buffers and video memory */
-       ret = __vb2_queue_alloc(q, create->memory, num_buffers,
+       allocated_buffers = __vb2_queue_alloc(q, create->memory, num_buffers,
                                num_planes);
-       if (ret == 0) {
+       if (allocated_buffers == 0) {
                dprintk(1, "Memory allocation failed\n");
                return -ENOMEM;
        }
 
-       allocated_buffers = ret;
-
        /*
         * Check if driver can handle the so far allocated number of buffers.
         */
-       if (ret < num_buffers) {
-               num_buffers = ret;
+       if (allocated_buffers < num_buffers) {
+               num_buffers = allocated_buffers;
 
                /*
                 * q->num_buffers contains the total number of buffers, that the
@@ -966,6 +967,10 @@ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create
        q->num_buffers += allocated_buffers;
 
        if (ret < 0) {
+               /*
+                * Note: __vb2_queue_free() will subtract 'allocated_buffers'
+                * from q->num_buffers.
+                */
                __vb2_queue_free(q, allocated_buffers);
                return -ENOMEM;
        }