I made the condition of the wait_event_timeout call in
gm12u320_fb_update_work a helper which takes a mutex to make sure
that any writes to fb_update.run or fb_update.fb from other CPU cores
are seen before the check is done.
This is not necessary as the wait_event helpers contain the necessary
barriers for this themselves.
More over it is harmfull since by the time the check is done the task
is no longer in the TASK_RUNNING state and calling mutex_lock while not
in task-running is not allowed, leading to this warning when the kernel
is build with some extra locking checks enabled:
[11947.450011] do not call blocking ops when !TASK_RUNNING; state=2 set at
[<00000000e4306de6>] prepare_to_wait_event+0x61/0x190
This commit fixes this by dropping the helper and simply directly
checking the condition (without unnecessary locking) in the
wait_event_timeout call.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/gpu/drm/tiny/gm12u320.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/tiny/gm12u320.c b/drivers/gpu/drm/tiny/gm12u320.c
index 4c47aa4de09b..4d66765b1125 100644
--- a/drivers/gpu/drm/tiny/gm12u320.c
+++ b/drivers/gpu/drm/tiny/gm12u320.c
@@ -342,17 +342,6 @@ static void gm12u320_copy_fb_to_blocks(struct gm12u320_device *gm12u320)
mutex_unlock(&gm12u320->fb_update.lock);
}
-static int gm12u320_fb_update_ready(struct gm12u320_device *gm12u320)
-{
- int ret;
-
- mutex_lock(&gm12u320->fb_update.lock);
- ret = !gm12u320->fb_update.run || gm12u320->fb_update.fb != NULL;
- mutex_unlock(&gm12u320->fb_update.lock);
-
- return ret;
-}
-
static void gm12u320_fb_update_work(struct work_struct *work)
{
struct gm12u320_device *gm12u320 =
@@ -426,7 +415,8 @@ static void gm12u320_fb_update_work(struct work_struct *work)
* switches back to showing its logo.
*/
wait_event_timeout(gm12u320->fb_update.waitq,
- gm12u320_fb_update_ready(gm12u320),
+ !gm12u320->fb_update.run ||
+ gm12u320->fb_update.fb != NULL,
IDLE_TIMEOUT);
}
return;
--
2.22.0
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
