Haven't fully understood the usage of wake_event_interruptible, now I have read
its description. Sorry for the lame patch.
Please find a fixed version below.
Patch allows for blocking or nonblocking io on the ngene sec0 device.
It also enforces one reader and one writer at a time.
Signed-off-by: Issa Gorissen <flo...@usa.net>
--
--- a/linux/drivers/media/dvb/ngene/ngene-dvb.c 2011-05-10 19:11:21.000000000
+0200
+++ b/linux/drivers/media/dvb/ngene/ngene-dvb.c 2011-06-21 23:46:09.000000000
+0200
@@ -53,15 +53,30 @@ static ssize_t ts_write(struct file *fil
struct dvb_device *dvbdev = file->private_data;
struct ngene_channel *chan = dvbdev->priv;
struct ngene *dev = chan->dev;
+ int avail = 0;
+ char nonblock = file->f_flags & O_NONBLOCK;
- if (wait_event_interruptible(dev->tsout_rbuf.queue,
- dvb_ringbuffer_free
- (&dev->tsout_rbuf) >= count) < 0)
+ if (!count)
return 0;
- dvb_ringbuffer_write(&dev->tsout_rbuf, buf, count);
+ if (nonblock) {
+ avail = dvb_ringbuffer_free(&dev->tsout_rbuf);
+ if (!avail)
+ return -EAGAIN;
+ if (count < avail)
+ avail = count;
+ } else {
+ if (wait_event_interruptible(dev->tsout_rbuf.queue,
+ dvb_ringbuffer_free
+ (&dev->tsout_rbuf) >= count) < 0)
+ return -EINTR;
+
+ avail = count;
+ }
+
+ dvb_ringbuffer_write(&dev->tsout_rbuf, buf, avail);
+ return avail;
- return count;
}
static ssize_t ts_read(struct file *file, char *buf,
@@ -70,22 +85,29 @@ static ssize_t ts_read(struct file *file
struct dvb_device *dvbdev = file->private_data;
struct ngene_channel *chan = dvbdev->priv;
struct ngene *dev = chan->dev;
- int left, avail;
+ int avail = 0;
+ char nonblock = file->f_flags & O_NONBLOCK;
- left = count;
- while (left) {
- if (wait_event_interruptible(
- dev->tsin_rbuf.queue,
- dvb_ringbuffer_avail(&dev->tsin_rbuf) > 0) < 0)
- return -EAGAIN;
+ if (!count)
+ return 0;
+
+ if (nonblock) {
avail = dvb_ringbuffer_avail(&dev->tsin_rbuf);
- if (avail > left)
- avail = left;
- dvb_ringbuffer_read_user(&dev->tsin_rbuf, buf, avail);
- left -= avail;
- buf += avail;
+ if (!avail)
+ return -EAGAIN;
+ if (avail > count)
+ avail = count;
+ } else {
+ if (wait_event_interruptible(dev->tsin_rbuf.queue,
+ dvb_ringbuffer_avail
+ (&dev->tsin_rbuf) >= count) < 0)
+ return -EINTR;
+
+ avail = count;
}
- return count;
+
+ dvb_ringbuffer_read_user(&dev->tsin_rbuf, buf, avail);
+ return avail;
}
static const struct file_operations ci_fops = {
@@ -98,9 +120,9 @@ static const struct file_operations ci_f
struct dvb_device ngene_dvbdev_ci = {
.priv = 0,
- .readers = -1,
- .writers = -1,
- .users = -1,
+ .readers = 1,
+ .writers = 1,
+ .users = 2,
.fops = &ci_fops,
};
--
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