staging: comedi: drivers: let core handle freeing s->private

Introduce a new subdevice runflags, SRF_FREE_SPRIV, and a new helper
function, comedi_set_spriv(), that the drivers can use to set the
comedi_subdevice private data pointer. The helper function will also
set SRF_FREE_SPRIV to allow the comedi core to automatically free the
subdevice private data during the cleanup_device() stage of the detach.

Currently s->private is only allocated by the 8255, addi_watchdog,
amplc_dio200_common, and ni_65xx drivers. All users of those drivers
can then have the comedi_spriv_free() calls removed and in many cases
the (*detach) can then simply be the appropriate comedi core provided
function.

The ni_65xx driver uses a helper function, ni_65xx_alloc_subdevice_private(),
to allocate the private data. Refactor the function to return an errno
or call comedi_set_spriv() instead of returning a pointer to the private
data and requiring the caller to handle it.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_fops.c

@@ -531,6 +531,21 @@ static bool comedi_is_subdevice_idle(struct comedi_subdevice *s)
 	return (runflags & (SRF_ERROR | SRF_RUNNING)) ? false : true;
 }
 
+/**
+ * comedi_set_spriv() - Set the subdevice private data pointer.
+ * @s: comedi_subdevice struct
+ * @data: pointer to the private data
+ *
+ * This also sets the subdevice runflags to allow the core to automatically
+ * free the private data during the detach.
+ */
+void comedi_set_spriv(struct comedi_subdevice *s, void *data)
+{
+	s->private = data;
+	comedi_set_subdevice_runflags(s, ~0, SRF_FREE_SPRIV);
+}
+EXPORT_SYMBOL_GPL(comedi_set_spriv);
+
 /*
    This function restores a subdevice to an idle state.
  */

drivers/staging/comedi/comedidev.h

@@ -265,10 +265,12 @@ enum subdevice_runflags {
 	/* indicates an COMEDI_CB_ERROR event has occurred since the last
 	 * command was started */
 	SRF_ERROR = 0x00000004,
-	SRF_RUNNING = 0x08000000
+	SRF_RUNNING = 0x08000000,
+	SRF_FREE_SPRIV = 0x80000000,	/* free s->private on detach */
 };
 
 bool comedi_is_subdevice_running(struct comedi_subdevice *s);
+void comedi_set_spriv(struct comedi_subdevice *s, void *data);
 
 int comedi_check_chanlist(struct comedi_subdevice *s,
 			  int n,
@@ -356,8 +358,6 @@ void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
 
 int comedi_alloc_subdevices(struct comedi_device *, int);
 
-void comedi_spriv_free(struct comedi_device *, int subdev_num);
-
 int comedi_load_firmware(struct comedi_device *, struct device *,
 			 const char *name,
 			 int (*cb)(struct comedi_device *,

drivers/staging/comedi/drivers.c

@@ -83,18 +83,6 @@ int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
 }
 EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);
 
-void comedi_spriv_free(struct comedi_device *dev, int subdev_num)
-{
-	struct comedi_subdevice *s;
-
-	if (dev->subdevices && subdev_num < dev->n_subdevices) {
-		s = &dev->subdevices[subdev_num];
-		kfree(s->private);
-		s->private = NULL;
-	}
-}
-EXPORT_SYMBOL_GPL(comedi_spriv_free);
-
 static void cleanup_device(struct comedi_device *dev)
 {
 	int i;
@@ -103,6 +91,8 @@ static void cleanup_device(struct comedi_device *dev)
 	if (dev->subdevices) {
 		for (i = 0; i < dev->n_subdevices; i++) {
 			s = &dev->subdevices[i];
+			if (s->runflags & SRF_FREE_SPRIV)
+				kfree(s->private);
 			comedi_free_subdevice_minor(s);
 			if (s->async) {
 				comedi_buf_alloc(dev, s, 0);

drivers/staging/comedi/drivers/8255.c

@@ -288,12 +288,11 @@ int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
 	if (!spriv)
 		return -ENOMEM;
+	comedi_set_spriv(s, spriv);
 
 	spriv->iobase	= iobase;
 	spriv->io	= io ? io : subdev_8255_io;
 
-	s->private	= spriv;
-
 	s->type		= COMEDI_SUBD_DIO;
 	s->subdev_flags	= SDF_READABLE | SDF_WRITABLE;
 	s->n_chan	= 24;
@@ -386,7 +385,6 @@ static void dev_8255_detach(struct comedi_device *dev)
 			spriv = s->private;
 			release_region(spriv->iobase, _8255_SIZE);
 		}
-		comedi_spriv_free(dev, i);
 	}
 }
 

drivers/staging/comedi/drivers/8255_pci.c

@@ -238,10 +238,7 @@ static int pci_8255_auto_attach(struct comedi_device *dev,
 static void pci_8255_detach(struct comedi_device *dev)
 {
 	struct pci_8255_private *devpriv = dev->private;
-	int i;
 
-	for (i = 0; i < dev->n_subdevices; i++)
-		comedi_spriv_free(dev, i);
 	if (devpriv && devpriv->mmio_base)
 		iounmap(devpriv->mmio_base);
 	comedi_pci_disable(dev);

drivers/staging/comedi/drivers/addi_apci_1516.c

@@ -196,7 +196,6 @@ static void apci1516_detach(struct comedi_device *dev)
 {
 	if (dev->iobase)
 		apci1516_reset(dev);
-	comedi_spriv_free(dev, 2);
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/addi_apci_2032.c

@@ -347,7 +347,6 @@ static void apci2032_detach(struct comedi_device *dev)
 		free_irq(dev->irq, dev);
 	if (dev->read_subdev)
 		kfree(dev->read_subdev->private);
-	comedi_spriv_free(dev, 1);
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/addi_apci_2200.c

@@ -123,7 +123,6 @@ static void apci2200_detach(struct comedi_device *dev)
 {
 	if (dev->iobase)
 		apci2200_reset(dev);
-	comedi_spriv_free(dev, 2);
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/addi_watchdog.c

@@ -129,11 +129,10 @@ int addi_watchdog_init(struct comedi_subdevice *s, unsigned long iobase)
 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
 	if (!spriv)
 		return -ENOMEM;
+	comedi_set_spriv(s, spriv);
 
 	spriv->iobase = iobase;
 
-	s->private	= spriv;
-
 	s->type		= COMEDI_SUBD_TIMER;
 	s->subdev_flags	= SDF_WRITEABLE;
 	s->n_chan	= 1;

drivers/staging/comedi/drivers/adv_pci_dio.c

@@ -1173,19 +1173,11 @@ static int pci_dio_auto_attach(struct comedi_device *dev,
 static void pci_dio_detach(struct comedi_device *dev)
 {
 	struct pci_dio_private *devpriv = dev->private;
-	struct comedi_subdevice *s;
-	int i;
 
 	if (devpriv) {
 		if (devpriv->valid)
 			pci_dio_reset(dev);
 	}
-	for (i = 0; i < dev->n_subdevices; i++) {
-		s = &dev->subdevices[i];
-		if (s->type == COMEDI_SUBD_DIO)
-			comedi_spriv_free(dev, i);
-		s->private = NULL; /* some private data is static */
-	}
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/aio_aio12_8.c

@@ -255,17 +255,11 @@ static int aio_aio12_8_attach(struct comedi_device *dev,
 	return 0;
 }
 
-static void aio_aio12_8_detach(struct comedi_device *dev)
-{
-	comedi_spriv_free(dev, 2);
-	comedi_legacy_detach(dev);
-}
-
 static struct comedi_driver aio_aio12_8_driver = {
 	.driver_name	= "aio_aio12_8",
 	.module		= THIS_MODULE,
 	.attach		= aio_aio12_8_attach,
-	.detach		= aio_aio12_8_detach,
+	.detach		= comedi_legacy_detach,
 	.board_name	= &board_types[0].name,
 	.num_names	= ARRAY_SIZE(board_types),
 	.offset		= sizeof(struct aio12_8_boardtype),

drivers/staging/comedi/drivers/amplc_dio200_common.c

@@ -559,6 +559,7 @@ dio200_subdev_intr_init(struct comedi_device *dev, struct comedi_subdevice *s,
 	subpriv = kzalloc(sizeof(*subpriv), GFP_KERNEL);
 	if (!subpriv)
 		return -ENOMEM;
+	comedi_set_spriv(s, subpriv);
 
 	subpriv->ofs = offset;
 	subpriv->valid_isns = valid_isns;
@@ -568,7 +569,6 @@ dio200_subdev_intr_init(struct comedi_device *dev, struct comedi_subdevice *s,
 		/* Disable interrupt sources. */
 		dio200_write8(dev, subpriv->ofs, 0);
 
-	s->private = subpriv;
 	s->type = COMEDI_SUBD_DI;
 	s->subdev_flags = SDF_READABLE | SDF_CMD_READ;
 	if (layout->has_int_sce) {
@@ -886,8 +886,8 @@ dio200_subdev_8254_init(struct comedi_device *dev, struct comedi_subdevice *s,
 	subpriv = kzalloc(sizeof(*subpriv), GFP_KERNEL);
 	if (!subpriv)
 		return -ENOMEM;
+	comedi_set_spriv(s, subpriv);
 
-	s->private = subpriv;
 	s->type = COMEDI_SUBD_COUNTER;
 	s->subdev_flags = SDF_WRITABLE | SDF_READABLE;
 	s->n_chan = 3;
@@ -1022,8 +1022,10 @@ static int dio200_subdev_8255_init(struct comedi_device *dev,
 	subpriv = kzalloc(sizeof(*subpriv), GFP_KERNEL);
 	if (!subpriv)
 		return -ENOMEM;
+	comedi_set_spriv(s, subpriv);
+
 	subpriv->ofs = offset;
-	s->private = subpriv;
+
 	s->type = COMEDI_SUBD_DIO;
 	s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
 	s->n_chan = 24;
@@ -1225,28 +1227,11 @@ void amplc_dio200_common_detach(struct comedi_device *dev)
 {
 	const struct dio200_board *thisboard = comedi_board(dev);
 	struct dio200_private *devpriv = dev->private;
-	const struct dio200_layout *layout;
-	unsigned n;
 
 	if (!thisboard || !devpriv)
 		return;
 	if (dev->irq)
 		free_irq(dev->irq, dev);
-	if (dev->subdevices) {
-		layout = dio200_board_layout(thisboard);
-		for (n = 0; n < dev->n_subdevices; n++) {
-			switch (layout->sdtype[n]) {
-			case sd_8254:
-			case sd_8255:
-			case sd_intr:
-				comedi_spriv_free(dev, n);
-				break;
-			case sd_timer:
-			default:
-				break;
-			}
-		}
-	}
 }
 EXPORT_SYMBOL_GPL(amplc_dio200_common_detach);
 

drivers/staging/comedi/drivers/amplc_pc236.c

@@ -538,7 +538,6 @@ static void pc236_detach(struct comedi_device *dev)
 		return;
 	if (dev->iobase)
 		pc236_intr_disable(dev);
-	comedi_spriv_free(dev, 0);
 	if (is_isa_board(thisboard)) {
 		comedi_legacy_detach(dev);
 	} else if (is_pci_board(thisboard)) {

drivers/staging/comedi/drivers/amplc_pci230.c

@@ -2830,7 +2830,6 @@ static void pci230_detach(struct comedi_device *dev)
 {
 	struct pci_dev *pcidev = comedi_to_pci_dev(dev);
 
-	comedi_spriv_free(dev, 2);
 	if (dev->irq)
 		free_irq(dev->irq, dev);
 	comedi_pci_disable(dev);

drivers/staging/comedi/drivers/cb_pcidas.c

@@ -1602,7 +1602,6 @@ static void cb_pcidas_detach(struct comedi_device *dev)
 	}
 	if (dev->irq)
 		free_irq(dev->irq, dev);
-	comedi_spriv_free(dev, 2);
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/cb_pcidas64.c

@@ -4158,7 +4158,6 @@ static void detach(struct comedi_device *dev)
 					devpriv->ao_dma_desc_bus_addr);
 		}
 	}
-	comedi_spriv_free(dev, 4);
 	comedi_pci_disable(dev);
 }
 

drivers/staging/comedi/drivers/cb_pcidda.c

@@ -393,18 +393,11 @@ static int cb_pcidda_auto_attach(struct comedi_device *dev,
 	return 0;
 }
 
-static void cb_pcidda_detach(struct comedi_device *dev)
-{
-	comedi_spriv_free(dev, 1);
-	comedi_spriv_free(dev, 2);
-	comedi_pci_disable(dev);
-}
-
 static struct comedi_driver cb_pcidda_driver = {
 	.driver_name	= "cb_pcidda",
 	.module		= THIS_MODULE,
 	.auto_attach	= cb_pcidda_auto_attach,
-	.detach		= cb_pcidda_detach,
+	.detach		= comedi_pci_disable,
 };
 
 static int cb_pcidda_pci_probe(struct pci_dev *dev,

drivers/staging/comedi/drivers/cb_pcimdda.c

@@ -192,17 +192,11 @@ static int cb_pcimdda_auto_attach(struct comedi_device *dev,
 	return 1;
 }
 
-static void cb_pcimdda_detach(struct comedi_device *dev)
-{
-	comedi_spriv_free(dev, 1);
-	comedi_pci_disable(dev);
-}
-
 static struct comedi_driver cb_pcimdda_driver = {
 	.driver_name	= "cb_pcimdda",
 	.module		= THIS_MODULE,
 	.auto_attach	= cb_pcimdda_auto_attach,
-	.detach		= cb_pcimdda_detach,
+	.detach		= comedi_pci_disable,
 };
 
 static int cb_pcimdda_pci_probe(struct pci_dev *dev,

drivers/staging/comedi/drivers/daqboard2000.c

@@ -747,7 +747,6 @@ static void daqboard2000_detach(struct comedi_device *dev)
 {
 	struct daqboard2000_private *devpriv = dev->private;
 
-	comedi_spriv_free(dev, 2);
 	if (dev->irq)
 		free_irq(dev->irq, dev);
 	if (devpriv) {

drivers/staging/comedi/drivers/das08.c

@@ -560,12 +560,6 @@ int das08_common_attach(struct comedi_device *dev, unsigned long iobase)
 }
 EXPORT_SYMBOL_GPL(das08_common_attach);
 
-void das08_common_detach(struct comedi_device *dev)
-{
-	comedi_spriv_free(dev, 4);
-}
-EXPORT_SYMBOL_GPL(das08_common_detach);
-
 static int __init das08_init(void)
 {
 	return 0;