提交 774dd5d9 编写于 作者: D Dyks, Axel (XL) 提交者: Mauro Carvalho Chehab

V4L/DVB (4090): Fix cinergyt2_poll() to allow non-blocking IO on frontend

cinergyt2_poll()" shouldn't return (POLLIN | POLLRDNORM | POLLPRI) when
there are no pending events. User space programs that do non-bocking IO
using "select()" and/or "poll()" would otherwise produce high system load.
Acked-by: NAndreas Oberritter <obi@linuxtv.org>
Signed-off-by: NAxel Dyks <xl@xlsigned.net>
Acked-by: NAndreas Oberritter <obi@linuxtv.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@infradead.org>
上级 be4f4519
......@@ -544,15 +544,19 @@ static unsigned int cinergyt2_poll (struct file *file, struct poll_table_struct
{
struct dvb_device *dvbdev = file->private_data;
struct cinergyt2 *cinergyt2 = dvbdev->priv;
unsigned int mask = 0;
if (cinergyt2->disconnect_pending || mutex_lock_interruptible(&cinergyt2->sem))
return -ERESTARTSYS;
poll_wait(file, &cinergyt2->poll_wq, wait);
if (cinergyt2->pending_fe_events != 0)
mask |= (POLLIN | POLLRDNORM | POLLPRI);
mutex_unlock(&cinergyt2->sem);
return (POLLIN | POLLRDNORM | POLLPRI);
return mask;
}
......
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