ni_mio_common: 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_mio_common.c b/comedi/drivers/ni_mio_common.c
index 41385744333a043f923bb45edcaa88609fa5cfcc..ce7725d437f5227c7669c10a3a87c74e008c197d 100644 (file)
--- a/comedi/drivers/ni_mio_common.c
+++ b/comedi/drivers/ni_mio_common.c
@@ -2925,6 +2925,9 @@ static int ni_ao_config_chanlist(comedi_device * dev, comedi_subdevice * s,
 static int ni_ao_insn_read(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->ao[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -2936,6 +2939,9 @@ static int ni_ao_insn_write(comedi_device * dev, comedi_subdevice * s,
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int invert;
 
+       if (insn->n == 0)
+               return 0;
+
        invert = ni_ao_config_chanlist(dev, s, &insn->chanspec, 1, 0);
 
        devpriv->ao[chan] = data[0];
@@ -2955,6 +2961,9 @@ static int ni_ao_insn_write_671x(comedi_device * dev, comedi_subdevice * s,
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int invert;
 
+       if (insn->n == 0)
+               return 0;
+
        ao_win_out(1 << chan, AO_Immediate_671x);
        invert = 1 << (boardtype.aobits - 1);
 
@@ -4212,6 +4221,9 @@ static unsigned ni_gpct_read_register(struct ni_gpct *counter,
 static int ni_freq_out_insn_read(comedi_device * dev,
        comedi_subdevice * s, comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->clock_and_fout & FOUT_Divider_mask;
        return 1;
 }
@@ -4219,6 +4231,9 @@ static int ni_freq_out_insn_read(comedi_device * dev,
 static int ni_freq_out_insn_write(comedi_device * dev,
        comedi_subdevice * s, comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        devpriv->clock_and_fout &= ~FOUT_Enable;
        devpriv->stc_writew(dev, devpriv->clock_and_fout,
                Clock_and_FOUT_Register);
@@ -4627,6 +4642,9 @@ static int ni_8255_callback(int dir, int port, int data, unsigned long arg)
 static int ni_eeprom_insn_read(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = ni_read_eeprom(dev, CR_CHAN(insn->chanspec));
 
        return 1;
@@ -4663,6 +4681,9 @@ static int ni_read_eeprom(comedi_device * dev, int addr)
 static int ni_m_series_eeprom_insn_read(comedi_device * dev,
        comedi_subdevice * s, comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->eeprom_buffer[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -4810,6 +4831,9 @@ static void ni_write_caldac(comedi_device * dev, int addr, int val);
 static int ni_calib_insn_write(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        ni_write_caldac(dev, CR_CHAN(insn->chanspec), data[0]);
 
        return 1;
@@ -4818,6 +4842,9 @@ static int ni_calib_insn_write(comedi_device * dev, comedi_subdevice * s,
 static int ni_calib_insn_read(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->caldacs[CR_CHAN(insn->chanspec)];
 
        return 1;