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 <[email protected]> --- 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; + } continue; } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
