cb_pcidas: don't access *data when insn-en == 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/cb_pcidas.c b/comedi/drivers/cb_pcidas.c
index 39f48bb9d4f5fba2a7103c989c808163018f0bd2..46f75629a6b94b3e77e1f631478b469346d375aa 100644 (file)
--- a/comedi/drivers/cb_pcidas.c
+++ b/comedi/drivers/cb_pcidas.c
@@ -873,6 +873,9 @@ static int cb_pcidas_ao_nofifo_winsn(comedi_device * dev, comedi_subdevice * s,
        int channel;
        unsigned long flags;
 
+       if (insn->n == 0)
+               return 0;
+
        // set channel and range
        channel = CR_CHAN(insn->chanspec);
        comedi_spin_lock_irqsave(&dev->spinlock, flags);
@@ -898,6 +901,9 @@ static int cb_pcidas_ao_fifo_winsn(comedi_device * dev, comedi_subdevice * s,
        int channel;
        unsigned long flags;
 
+       if (insn->n == 0)
+               return 0;
+
        // clear dac fifo
        outw(0, devpriv->ao_registers + DACFIFOCLR);
 
@@ -926,6 +932,9 @@ static int cb_pcidas_ao_fifo_winsn(comedi_device * dev, comedi_subdevice * s,
 static int cb_pcidas_ao_readback_insn(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;
@@ -937,6 +946,9 @@ static int eeprom_read_insn(comedi_device * dev, comedi_subdevice * s,
        uint8_t nvram_data;
        int retval;
 
+       if (insn->n == 0)
+               return 0;
+
        retval = nvram_read(dev, CR_CHAN(insn->chanspec), &nvram_data);
        if (retval < 0)
                return retval;
@@ -951,12 +963,18 @@ static int caldac_write_insn(comedi_device * dev, comedi_subdevice * s,
 {
        const unsigned int channel = CR_CHAN(insn->chanspec);
 
+       if (insn->n == 0)
+               return 0;
+
        return caldac_8800_write(dev, channel, data[0]);
 }
 
 static int caldac_read_insn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->caldac_value[CR_CHAN(insn->chanspec)];
 
        return 1;
@@ -986,12 +1004,18 @@ static int dac08_write(comedi_device * dev, lsampl_t value)
 static int dac08_write_insn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        return dac08_write(dev, data[0]);
 }
 
 static int dac08_read_insn(comedi_device * dev, comedi_subdevice * s,
        comedi_insn * insn, lsampl_t * data)
 {
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->dac08_value;
 
        return 1;
@@ -1025,6 +1049,9 @@ static int trimpot_write_insn(comedi_device * dev, comedi_subdevice * s,
 {
        unsigned int channel = CR_CHAN(insn->chanspec);
 
+       if (insn->n == 0)
+               return 0;
+
        return cb_pcidas_trimpot_write(dev, channel, data[0]);
 }
 
@@ -1033,6 +1060,9 @@ static int trimpot_read_insn(comedi_device * dev, comedi_subdevice * s,
 {
        unsigned int channel = CR_CHAN(insn->chanspec);
 
+       if (insn->n == 0)
+               return 0;
+
        data[0] = devpriv->trimpot_value[channel];
 
        return 1;