comedi: quatech_daqp_cs: Fix sanity check in interrupt handler

The driver requests an interrupt handler for the device before it is
fully set up.

For safety, the interrupt handler checks the dev->attached flag to
ensure the device is fully set up, but it currently does that after
dereferencing the dev->read_dev pointer which may be NULL if
dev->attached is false.  Move the check to avoid the possible null
pointer dereference.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260618102949.26607-12-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions