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().
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
