ni_labpc: don't access *data when insn->n == 0

Due to recent change to do_insnlist_ioctl() and do_insn_ioctl(), the
'data' pointer will be NULL when insn->n == 0.  Do not access *data
in this case.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

diff --git a/comedi/drivers/ni_labpc.c b/comedi/drivers/ni_labpc.c
index 93dab42930e4074a841f4a56545498daa21ae965..94764f23893a206ee1547f9c080add30042230de 100644 (file)
--- a/comedi/drivers/ni_labpc.c
+++ b/comedi/drivers/ni_labpc.c
@@ -1594,6 +1594,9 @@ static int labpc_ao_winsn(comedi_device * dev, comedi_subdevice * s,
        unsigned long flags;
        int lsb, msb;
 
+       if (insn->n == 0)
+               return 0;
+
        channel = CR_CHAN(insn->chanspec);
 
        // turn off pacing of analog output channel
@@ -1631,6 +1634,9 @@ static int labpc_ao_winsn(comedi_device * dev, comedi_subdevice * s,
 static int labpc_ao_rinsn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->ao_value[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -1639,6 +1645,9 @@ static int labpc_ao_rinsn(comedi_device * dev, comedi_subdevice * s,
 static int labpc_calib_read_insn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->caldac[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -1649,6 +1658,9 @@ static int labpc_calib_write_insn(comedi_device * dev, comedi_subdevice * s,
 {
        int channel = CR_CHAN(insn->chanspec);
 
+       if (insn->n == 0)
+               return 0;
+
        write_caldac(dev, channel, data[0]);
        return 1;
 }
@@ -1656,6 +1668,9 @@ static int labpc_calib_write_insn(comedi_device * dev, comedi_subdevice * s,
 static int labpc_eeprom_read_insn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->eeprom_data[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -1673,6 +1688,9 @@ static int labpc_eeprom_write_insn(comedi_device * dev, comedi_subdevice * s,
                return -EINVAL;
        }
 
+       if (insn->n == 0)
+               return 0;
+
        ret = labpc_eeprom_write(dev, channel, data[0]);
        if (ret < 0)
                return ret;