staging: comedi: return error on "read" if no command set up
The "read" file operation handler, `comedi_read()` returns an error for pretty much any condition that prevents a "read" going ahead. One of the conditions that prevents a "read" going ahead is that no asynchronous command has been set up, but that currently results in a return value of 0 (unless COMEDI instructions are being processed or an asynchronous command has been set up by a different file object). Change it to return `-EINVAL` in this case. Signed-off-by: NIan Abbott <abbotti@mev.co.uk> Reviewed-by: NH Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing
想要评论请 注册 或 登录