[RFCv2 PATCH 10/12] stk-webcam: fix read() handling when reqbufs was already called.

[Hans Verkuil]

From: Hans Verkuil <hans.verk...@cisco.com>

Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
Tested-by: Arvydas Sidorenko <asi...@gmail.com>
---
 drivers/media/usb/stkwebcam/stk-webcam.c |    3 ++-
 drivers/media/usb/stkwebcam/stk-webcam.h |    1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/stkwebcam/stk-webcam.c 
b/drivers/media/usb/stkwebcam/stk-webcam.c
index f3fabda..e3442de 100644
--- a/drivers/media/usb/stkwebcam/stk-webcam.c
+++ b/drivers/media/usb/stkwebcam/stk-webcam.c
@@ -616,7 +616,7 @@ static ssize_t stk_read(struct file *fp, char __user *buf,
 
        if (!is_present(dev))
                return -EIO;
-       if (dev->owner && dev->owner != fp)
+       if (dev->owner && (!dev->reading || dev->owner != fp))
                return -EBUSY;
        dev->owner = fp;
        if (!is_streaming(dev)) {
@@ -624,6 +624,7 @@ static ssize_t stk_read(struct file *fp, char __user *buf,
                        || stk_allocate_buffers(dev, 3)
                        || stk_start_stream(dev))
                        return -ENOMEM;
+               dev->reading = 1;
                spin_lock_irqsave(&dev->spinlock, flags);
                for (i = 0; i < dev->n_sbufs; i++) {
                        list_add_tail(&dev->sio_bufs[i].list, &dev->sio_avail);
diff --git a/drivers/media/usb/stkwebcam/stk-webcam.h 
b/drivers/media/usb/stkwebcam/stk-webcam.h
index 03550cf..9bbfa3d 100644
--- a/drivers/media/usb/stkwebcam/stk-webcam.h
+++ b/drivers/media/usb/stkwebcam/stk-webcam.h
@@ -118,6 +118,7 @@ struct stk_camera {
 
        int frame_size;
        /* Streaming buffers */
+       int reading;
        unsigned int n_sbufs;
        struct stk_sio_buffer *sio_bufs;
        struct list_head sio_avail;
-- 
1.7.10.4

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