linux-kernel - [PATCH] media: amphion: Move the blocking check_is

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Message-Id: <20231024052709.2897714-1-xiaolei.wang@windriver.com>
Date:   Tue, 24 Oct 2023 13:27:09 +0800
From:   Xiaolei Wang <xiaolei.wang@...driver.com>
To:     ming.qian@....com, eagle.zhou@....com, hverkuil-cisco@...all.nl,
        mchehab@...nel.org
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] media: amphion: Move the blocking check_is_responsed() out of wait event loop

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@...driver.com>

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