Incorrect handling of stop_streaming(), warnings in dmesg

[antonsviridenko]

[ 2794.047988] ------------[ cut here ]------------
[ 2794.047992] WARNING: CPU: 2 PID: 20517 at drivers/media/v4l2-core/videobuf2-core.c:1651 __vb2_queue_cancel+0x14b/0x230
[ 2794.047993] Modules linked in: ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat solo6x10 x86_pkg_temp_thermal
[ 2794.047997] CPU: 2 PID: 20517 Comm: ffplay Tainted: G        W       4.10.0-gentoo #1
[ 2794.047998] Hardware name: ASUS All Series/B85M-E, BIOS 2301 03/30/2015
[ 2794.047999] Call Trace:
[ 2794.048002]  dump_stack+0x4f/0x72
[ 2794.048005]  __warn+0xc7/0xf0
[ 2794.048006]  warn_slowpath_null+0x18/0x20
[ 2794.048007]  __vb2_queue_cancel+0x14b/0x230
[ 2794.048008]  vb2_core_streamoff+0x23/0x90
[ 2794.048009]  vb2_streamoff+0x24/0x50
[ 2794.048010]  vb2_ioctl_streamoff+0x3d/0x50
[ 2794.048012]  v4l_streamoff+0x15/0x20
[ 2794.048013]  __video_do_ioctl+0x25e/0x2f0
[ 2794.048015]  video_usercopy+0x279/0x520
[ 2794.048016]  ? v4l_enum_fmt+0x1330/0x1330
[ 2794.048017]  video_ioctl2+0x10/0x20
[ 2794.048019]  v4l2_ioctl+0xce/0xe0
[ 2794.048021]  do_vfs_ioctl+0x8b/0x5b0
[ 2794.048023]  ? __fget+0x72/0xa0
[ 2794.048024]  SyS_ioctl+0x74/0x80
[ 2794.048026]  entry_SYSCALL_64_fastpath+0x13/0x94
[ 2794.048027] RIP: 0033:0x7fc15d511b27
[ 2794.048028] RSP: 002b:00007ffef6337a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 2794.048029] RAX: ffffffffffffffda RBX: 00007fc14c503000 RCX: 00007fc15d511b27
[ 2794.048030] RDX: 00007ffef6337a94 RSI: 0000000040045613 RDI: 0000000000000006
[ 2794.048030] RBP: 0000000000000040 R08: 00000000ffffffff R09: 00007fc150001140
[ 2794.048031] R10: 0000000000000243 R11: 0000000000000246 R12: 00000000000002c0
[ 2794.048031] R13: 00000000000002c0 R14: 0000000000016000 R15: fffffffffffffff0
[ 2794.048032] ---[ end trace c41530fe2842a40e ]---

        /*
         * If you see this warning, then the driver isn't cleaning up properly
         * in stop_streaming(). See the stop_streaming() documentation in
         * videobuf2-core.h for more information how buffers should be returned
         * to vb2 in stop_streaming().
         */
        if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
                for (i = 0; i < q->num_buffers; ++i)
                        if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE)
                                vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR);
                /* Must be zero now */
                WARN_ON(atomic_read(&q->owned_by_drv_count));
        }

 * @stop_streaming:     called when 'streaming' state must be disabled; driver
 *                      should stop any DMA transactions or wait until they
 *                      finish and give back all buffers it got from &buf_queue
 *                      callback by calling vb2_buffer_done() with either
 *                      %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
 *                      vb2_wait_for_all_buffers() function

this is not performed by stop_streaming() in solo6x10 module