target/linux/brcm2708/patches-4.19/950-0696-Revert-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-bu.patch

   1 From 41079f8602ae082b78e33e7d326ff5f57b7d76e8 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.org>
   3 Date: Fri, 28 Jun 2019 11:30:49 +0100
   4 Subject: [PATCH 696/703] Revert "media: vb2: Allow reqbufs(0) with "in use"
   5  MMAP buffers"
   6
   7 This reverts commit a2c73e18c1f657de6d654f51effa0a94863abbd8.
   8 An alternative version was accepted upstream. Revert this patch to
   9 apply that one.
  10
  11 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
  12 ---
  13  .../media/common/videobuf2/videobuf2-core.c   | 23 +++++++++++++++++++
  14  1 file changed, 23 insertions(+)
  15
  16 --- a/drivers/media/common/videobuf2/videobuf2-core.c
  17 +++ b/drivers/media/common/videobuf2/videobuf2-core.c
  18 @@ -554,6 +554,20 @@ bool vb2_buffer_in_use(struct vb2_queue
  19  }
  20  EXPORT_SYMBOL(vb2_buffer_in_use);
  21
  22 +/*
  23 + * __buffers_in_use() - return true if any buffers on the queue are in use and
  24 + * the queue cannot be freed (by the means of REQBUFS(0)) call
  25 + */
  26 +static bool __buffers_in_use(struct vb2_queue *q)
  27 +{
  28 +       unsigned int buffer;
  29 +       for (buffer = 0; buffer < q->num_buffers; ++buffer) {
  30 +               if (vb2_buffer_in_use(q, q->bufs[buffer]))
  31 +                       return true;
  32 +       }
  33 +       return false;
  34 +}
  35 +
  36  void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
  37  {
  38         call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
  39 @@ -665,7 +679,16 @@ int vb2_core_reqbufs(struct vb2_queue *q
  40
  41         if (*count == 0 || q->num_buffers != 0 ||
  42             (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory)) {
  43 +               /*
  44 +                * We already have buffers allocated, so first check if they
  45 +                * are not in use and can be freed.
  46 +                */
  47                 mutex_lock(&q->mmap_lock);
  48 +               if (q->memory == VB2_MEMORY_MMAP && __buffers_in_use(q)) {
  49 +                       mutex_unlock(&q->mmap_lock);
  50 +                       dprintk(1, "memory in use, cannot free\n");
  51 +                       return -EBUSY;
  52 +               }
  53
  54                 /*
  55                  * Call queue_cancel to clean up any buffers in the PREPARED or