Commit ab705c8c authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

comedi: Fix some signed shift left operations 



Correct some left shifts of the signed integer constant 1 by some
unsigned number less than 32.  Change the constant to 1U to avoid
shifting a 1 into the sign bit.

The corrected functions are comedi_dio_insn_config(),
comedi_dio_update_state(), and __comedi_device_postconfig().

Fixes: e523c6c8 ("staging: comedi: drivers: introduce comedi_dio_insn_config()")
Fixes: 05e60b13 ("staging: comedi: drivers: introduce comedi_dio_update_state()")
Fixes: 09567cb4 ("staging: comedi: initialize subdevice s->io_bits in postconfig")
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20250707121555.65424-1-abbotti@mev.co.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 08ae4b20

drivers/comedi/drivers.c

+7 −7
Original line number Diff line number Diff line
@@ -339,10 +339,10 @@ int comedi_dio_insn_config(struct comedi_device *dev, 
			   unsigned int *data,

			   unsigned int mask)

{

	unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);

	unsigned int chan = CR_CHAN(insn->chanspec);



	if (!mask)

		mask = chan_mask;

	if (!mask && chan < 32)

		mask = 1U << chan;



	switch (data[0]) {

	case INSN_CONFIG_DIO_INPUT:
@@ -382,7 +382,7 @@ EXPORT_SYMBOL_GPL(comedi_dio_insn_config); 
unsigned int comedi_dio_update_state(struct comedi_subdevice *s,

				     unsigned int *data)

{

	unsigned int chanmask = (s->n_chan < 32) ? ((1 << s->n_chan) - 1)

	unsigned int chanmask = (s->n_chan < 32) ? ((1U << s->n_chan) - 1)

						 : 0xffffffff;

	unsigned int mask = data[0] & chanmask;

	unsigned int bits = data[1];
@@ -625,8 +625,8 @@ static int insn_rw_emulate_bits(struct comedi_device *dev, 
	if (insn->insn == INSN_WRITE) {

		if (!(s->subdev_flags & SDF_WRITABLE))

			return -EINVAL;

		_data[0] = 1 << (chan - base_chan);		    /* mask */

		_data[1] = data[0] ? (1 << (chan - base_chan)) : 0; /* bits */

		_data[0] = 1U << (chan - base_chan);		     /* mask */

		_data[1] = data[0] ? (1U << (chan - base_chan)) : 0; /* bits */

	}



	ret = s->insn_bits(dev, s, &_insn, _data);
@@ -709,7 +709,7 @@ static int __comedi_device_postconfig(struct comedi_device *dev) 


		if (s->type == COMEDI_SUBD_DO) {

			if (s->n_chan < 32)

				s->io_bits = (1 << s->n_chan) - 1;

				s->io_bits = (1U << s->n_chan) - 1;

			else

				s->io_bits = 0xffffffff;

		}