On Thursday, October 30, 2014 5:43 AM, Ian Abbott wrote:
> If a Comedi asynchronous command has been set up for data transfer in
> the "read" direction on the current "write" subdevice (for those
> subdevices that support both directions), don't allow the "write" file
> operation as that would mess with the data in the comedi data buffer
> that is written by the low-level comedi hardware driver.
>
> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
> ---
> drivers/staging/comedi/comedi_fops.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
> index 6805ec9..6328965 100644
> --- a/drivers/staging/comedi/comedi_fops.c
> +++ b/drivers/staging/comedi/comedi_fops.c
> @@ -2075,6 +2075,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
> retval = -EACCES;
> goto out;
> }
> + if (!(async->cmd.flags & CMDF_WRITE)) {
> + retval = -EINVAL;
> + goto out;
> + }
>
> add_wait_queue(&async->wait_head, &wait);
> on_wait_queue = true;
> @@ -2146,6 +2150,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
> retval = -EACCES;
> break;
> }
> + if (!(async->cmd.flags & CMDF_WRITE)) {
> + retval = -EINVAL;
> + break;
> + }
Same question as with PATCH 4/7.
Is this test needed in the while () loop. Also, are the s->busy tests needed here?
> continue;
> }
Regards,
Hartley
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