On 24/10/2023 09:12, Ming Qian wrote:
>> From: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
>> Sent: 2023年10月24日 13:27
>> To: Ming Qian <ming.qian@xxxxxxx>; Eagle Zhou <eagle.zhou@xxxxxxx>;
>> hverkuil-cisco@xxxxxxxxx; mchehab@xxxxxxxxxx
>> Cc: linux-media@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>> Subject: [EXT] [PATCH] media: amphion: Move the blocking
>> check_is_responsed() out of wait event loop
>>
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>>
>>
>> The blocking ops can't be used as a condition parameter of
>> wait_event_timeout(), otherwise we would get a warning like below:
>>
>> do not call blocking ops when !TASK_RUNNING; state=2
>> WARNING: CPU: 5 PID: 741 at kernel/sched/core.c:9859
>> __might_sleep+0x80/0xa4
>> CPU: 5 PID: 741 Comm: mxc_v4l2_vpu_te Tainted: G C 6.1.55-yocto-
>> standard #1
>> Hardware name: Freescale i.MX8QM MEK (DT)
>> pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc :
>> __might_sleep+0x80/0xa4 lr : __might_sleep+0x80/0xa4 sp : ffffffc0123738a0
>> x29: ffffffc0123738a0 x28: ffffffc009194c48 x27: ffffffc00bbc1050
>> x26: ffffff8814b282f0 x25: ffffff8814b280d0 x24: ffffff8814b28080
>> x23: 0000000000000001 x22: 0000000000000032 x21: ffffffc00bbc1000
>> x20: 000000000000011b x19: ffffffc009324670 x18: 00000000fffffffd
>> x17: 30303c5b20746120 x16: 74657320323d6574 x15: 617473203b474e49
>> x14: 00058b5b8b9aa1f1 x13: ffffffc00903cda0 x12: 00000000d744fcc9
>> x11: 000000000000001c x10: 00000000000009a0 x9 : ffffffc0090201f4
>> x8 : ffffff8828245000 x7 : 0000000000000001 x6 : 0000000000000001
>> x5 : 00000000410fd080 x4 : 0000000000000002 x3 : ffffff8815aab4c8
>> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff8828244600
>> Call trace:
>> __might_sleep+0x80/0xa4
>> mutex_lock+0x2c/0x80
>> sync_session_response+0x110/0x310
>> vpu_session_send_cmd+0x18c/0x244
>> vpu_session_start+0x38/0x70
>> vdec_start_session+0x1b4/0x3e0
>> vpu_vb2_start_streaming+0xa0/0x1c4
>> vb2_start_streaming+0x74/0x160
>> vb2_core_qbuf+0x488/0x650
>> vb2_qbuf+0x9c/0x100
>> v4l2_m2m_qbuf+0x7c/0x224
>> v4l2_m2m_ioctl_qbuf+0x20/0x2c
>> v4l_qbuf+0x50/0x6c
>> __video_do_ioctl+0x174/0x3f0
>> video_usercopy+0x210/0x7cc
>> video_ioctl2+0x20/0x30
>> v4l2_ioctl+0x48/0x6c
>>
>> It is not easy to convert the check_is_responsed() to a non-block function. In
>> order to fix this issue, use a unwinding implementation of
>> wait_event_timeout().
>
> Hi Xiaolei,
>
> Thanks for your patch, this issue is caused by calling mutex_lock() in condition parameter of
> wait_event_timeout(), I think we can fix this issue, then we can still use wait_event_timeout()
> instead of rewrite it.
Based on this reply I am marking this in patchwork as "Changes Requested".
Let me know if I misinterpreted this.
Regards,
Hans
>
> Ming
>
>>
>> Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
>>
>> squash! media: amphion: Move the blocking check_is_responsed() out of wait
>> event loop
>> ---
>> drivers/media/platform/amphion/vpu_cmds.c | 15 ++++++++++++++-
>> 1 file changed, 14 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/platform/amphion/vpu_cmds.c
>> b/drivers/media/platform/amphion/vpu_cmds.c
>> index c2337812573e..1abec8d9dad5 100644
>> --- a/drivers/media/platform/amphion/vpu_cmds.c
>> +++ b/drivers/media/platform/amphion/vpu_cmds.c
>> @@ -271,6 +271,7 @@ static bool check_is_responsed(struct vpu_inst *inst,
>> unsigned long key) static int sync_session_response(struct vpu_inst *inst,
>> unsigned long key, long timeout, int try) {
>> struct vpu_core *core;
>> + struct wait_queue_entry wq_entry;
>>
>> if (!inst || !inst->core)
>> return -EINVAL;
>> @@ -278,7 +279,19 @@ static int sync_session_response(struct vpu_inst *inst,
>> unsigned long key, long
>> core = inst->core;
>>
>> call_void_vop(inst, wait_prepare);
>> - wait_event_timeout(core->ack_wq, check_is_responsed(inst, key),
>> timeout);
>> + init_wait_entry(&wq_entry, 0);
>> + for (;;) {
>> + if (check_is_responsed(inst, key))
>> + break;
>> +
>> + prepare_to_wait_event(&core->ack_wq, &wq_entry,
>> + TASK_UNINTERRUPTIBLE);
>> +
>> + timeout = schedule_timeout(timeout);
>> + if (!timeout)
>> + break;
>> + }
>> +
>> + finish_wait(&core->ack_wq, &wq_entry);
>> call_void_vop(inst, wait_finish);
>>
>> if (!check_is_responsed(inst, key)) {
>> --
>> 2.25.1
>
