This patch is not so urgent, but should still be considered. Please
disregard the second comment below, which is not correct.
The original code, however, holds the spinlock for a long time. From
the structure of videobuf2, we could just hold qlock during buf_list and
sequence accesses.
On 2014-11-04 14:34, Dean Anderson wrote:
qlock spinlock controls access to buf_list and sequence.
qlock spinlock should not be locked during a copy to video buffers, an
operation that may sleep.
Signed-off-by: Dean Anderson <linux-dev@xxxxxxxxxxxx>
---
drivers/media/usb/s2255/s2255drv.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/drivers/media/usb/s2255/s2255drv.c
b/drivers/media/usb/s2255/s2255drv.c
index ccc0009..24c4413 100644
--- a/drivers/media/usb/s2255/s2255drv.c
+++ b/drivers/media/usb/s2255/s2255drv.c
@@ -558,27 +558,31 @@ static void s2255_fwchunk_complete(struct urb
*urb)
}
-static int s2255_got_frame(struct s2255_vc *vc, int jpgsize)
+static void s2255_got_frame(struct s2255_vc *vc, int jpgsize)
{
struct s2255_buffer *buf;
struct s2255_dev *dev = to_s2255_dev(vc->vdev.v4l2_dev);
unsigned long flags = 0;
- int rc = 0;
+
spin_lock_irqsave(&vc->qlock, flags);
if (list_empty(&vc->buf_list)) {
dprintk(dev, 1, "No active queue to serve\n");
- rc = -1;
- goto unlock;
+ spin_unlock_irqrestore(&vc->qlock, flags);
+ return;
}
buf = list_entry(vc->buf_list.next,
struct s2255_buffer, list);
list_del(&buf->list);
v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
+ buf->vb.v4l2_buf.field = vc->field;
+ buf->vb.v4l2_buf.sequence = vc->frame_count;
+ spin_unlock_irqrestore(&vc->qlock, flags);
+
s2255_fillbuff(vc, buf, jpgsize);
+ /* tell v4l buffer was filled */
+ vb2_buffer_done(&buf->vb, VB2_BUF_STATE_DONE);
dprintk(dev, 2, "%s: [buf] [%p]\n", __func__, buf);
-unlock:
- spin_unlock_irqrestore(&vc->qlock, flags);
- return rc;
+ return;
}
static const struct s2255_fmt *format_by_fourcc(int fourcc)
@@ -649,11 +653,6 @@ static void s2255_fillbuff(struct s2255_vc *vc,
}
dprintk(dev, 2, "s2255fill at : Buffer 0x%08lx size= %d\n",
(unsigned long)vbuf, pos);
- /* tell v4l buffer was filled */
- buf->vb.v4l2_buf.field = vc->field;
- buf->vb.v4l2_buf.sequence = vc->frame_count;
- v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
- vb2_buffer_done(&buf->vb, VB2_BUF_STATE_DONE);
}
--
1.9.1
--
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