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[media] IR: plug races in IR raw thread

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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>
This commit is contained in:
Maxim Levitsky 2010-09-06 18:26:06 -03:00 committed by Mauro Carvalho Chehab
parent c47d3e7f94
commit c6ef1e7fdc
2 changed files with 27 additions and 9 deletions
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2
drivers/media/IR/ir-core-priv.h
View file

@ -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_handler {
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 */

34
drivers/media/IR/ir-raw-event.c
View file

@ -39,22 +39,34 @@ static int ir_raw_event_thread(void *data)
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 @@ EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
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 @@ int ir_raw_event_register(struct input_dev *input_dev)
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);