From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
This patch removes BUG_ON in ir_raw_event_thread which IMO is a
over-kill, and this kills the ir_raw_event_thread too. With a bit of
additional logic in this patch, we nomore need to kill this thread.
Other disadvantage of having a BUG-ON is,
wake_up_process(dev->raw->thread) called on dead thread via
ir_raw_event_handle will result in total lockup in SMP system.
Advantage of this patch is ir-raw event thread is left in a usable state
even if the fifo does not have enough bytes.
This patch sets the thread into TASK_INTERRUPTIBLE if raw-fifo has less
then sizeof(struct ir_raw_event) bytes.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
---
Hi All,
BUG-ON in ir_raw_event_thread on an SMP system will put the system in an
un-usable state, because..
BUG-ON actually kill the ir-raw-event kernel thread and my driver is
calling wake_up_process on a dead thread via ir_raw_event_handle from
interrupt context, which is why the system is left unusable.
However, my patch simplifies code in ir_raw_event_thread and remove BUG_ON
forever.
BUG_ON in this thread is a bit of over kill in my opinion, as the thread is
not is not in a very bad state, that it has to be killed.
Thanks,
srini
drivers/media/rc/ir-raw.c | 8 +++-----
1 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/media/rc/ir-raw.c b/drivers/media/rc/ir-raw.c
index 95e6309..a820251 100644
--- a/drivers/media/rc/ir-raw.c
+++ b/drivers/media/rc/ir-raw.c
@@ -46,9 +46,9 @@ static int ir_raw_event_thread(void *data)
while (!kthread_should_stop()) {
spin_lock_irq(&raw->lock);
- retval = kfifo_out(&raw->kfifo, &ev, sizeof(ev));
+ retval = kfifo_len(&raw->kfifo);
- if (!retval) {
+ if (retval < sizeof(ev)) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop())
@@ -59,11 +59,9 @@ static int ir_raw_event_thread(void *data)
continue;
}
+ retval = kfifo_out(&raw->kfifo, &ev, sizeof(ev));
spin_unlock_irq(&raw->lock);
-
- BUG_ON(retval != sizeof(ev));
-
mutex_lock(&ir_raw_handler_lock);
list_for_each_entry(handler, &ir_raw_handler_list, list)
handler->decode(raw->dev, ev);
--
1.6.3.3
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