[media] IR: plug races in IR raw thread
Unfortunelly (my fault) the kernel thread that now handles IR processing
has classical races in regard to wakeup and stop.
This patch hopefully closes them all.
Tested with module reload running in a loop, while receiver is blasted
with IR data for 10 minutes.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/IR/ir-core-priv.h b/drivers/media/IR/ir-core-priv.h
index 0ad8ea3..90eb391 100644
--- a/drivers/media/IR/ir-core-priv.h
+++ b/drivers/media/IR/ir-core-priv.h
@@ -17,6 +17,7 @@
#define _IR_RAW_EVENT
#include <linux/slab.h>
+#include <linux/spinlock.h>
#include <media/ir-core.h>
struct ir_raw_handler {
@@ -33,6 +34,7 @@
struct ir_raw_event_ctrl {
struct list_head list; /* to keep track of raw clients */
struct task_struct *thread;
+ spinlock_t lock;
struct kfifo kfifo; /* fifo for the pulse/space durations */
ktime_t last_event; /* when last event occurred */
enum raw_event_type last_type; /* last event type */
diff --git a/drivers/media/IR/ir-raw-event.c b/drivers/media/IR/ir-raw-event.c
index 8e0e1b1..119b567 100644
--- a/drivers/media/IR/ir-raw-event.c
+++ b/drivers/media/IR/ir-raw-event.c
@@ -39,22 +39,34 @@
struct ir_raw_event ev;
struct ir_raw_handler *handler;
struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
+ int retval;
while (!kthread_should_stop()) {
- try_to_freeze();
- mutex_lock(&ir_raw_handler_lock);
+ spin_lock_irq(&raw->lock);
+ retval = kfifo_out(&raw->kfifo, &ev, sizeof(ev));
- while (kfifo_out(&raw->kfifo, &ev, sizeof(ev)) == sizeof(ev)) {
- list_for_each_entry(handler, &ir_raw_handler_list, list)
- handler->decode(raw->input_dev, ev);
- raw->prev_ev = ev;
+ if (!retval) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (kthread_should_stop())
+ set_current_state(TASK_RUNNING);
+
+ spin_unlock_irq(&raw->lock);
+ schedule();
+ continue;
}
- mutex_unlock(&ir_raw_handler_lock);
+ spin_unlock_irq(&raw->lock);
- set_current_state(TASK_INTERRUPTIBLE);
- schedule();
+
+ BUG_ON(retval != sizeof(ev));
+
+ mutex_lock(&ir_raw_handler_lock);
+ list_for_each_entry(handler, &ir_raw_handler_list, list)
+ handler->decode(raw->input_dev, ev);
+ raw->prev_ev = ev;
+ mutex_unlock(&ir_raw_handler_lock);
}
return 0;
@@ -232,11 +244,14 @@
void ir_raw_event_handle(struct input_dev *input_dev)
{
struct ir_input_dev *ir = input_get_drvdata(input_dev);
+ unsigned long flags;
if (!ir->raw)
return;
+ spin_lock_irqsave(&ir->raw->lock, flags);
wake_up_process(ir->raw->thread);
+ spin_unlock_irqrestore(&ir->raw->lock, flags);
}
EXPORT_SYMBOL_GPL(ir_raw_event_handle);
@@ -275,6 +290,7 @@
return rc;
}
+ spin_lock_init(&ir->raw->lock);
ir->raw->thread = kthread_run(ir_raw_event_thread, ir->raw,
"rc%u", (unsigned int)ir->devno);