[PATCH v3] media: dvb: Provide 4 devm variants

[PATCH v3] media: dvb: Provide 4 devm variants

[Marc Gonzalez]

Provide devm variants for automatic resource release on device removal.
Makes error-handling in probe() simpler, thus less error-prone.
Once all resources are devmanaged, remove() is no longer needed.

Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
---
Changes from v2:
x Handle dvb_register_adapter() return code correctly
Changes from v1:
x Simplify devm_dvb_register_adapter() implementation
x Add 3 more devm APIs
x Document them in devres.rst
---
 Documentation/driver-model/devres.rst |  6 ++++++
 drivers/media/dvb-core/dmxdev.c       | 13 +++++++++++++
 drivers/media/dvb-core/dvb_demux.c    | 13 +++++++++++++
 drivers/media/dvb-core/dvb_frontend.c | 13 +++++++++++++
 drivers/media/dvb-core/dvbdev.c       | 12 ++++++++++++
 include/media/dmxdev.h                |  3 +++
 include/media/dvb_demux.h             |  2 ++
 include/media/dvb_frontend.h          |  3 +++
 include/media/dvbdev.h                |  3 +++
 9 files changed, 68 insertions(+)

diff --git a/Documentation/driver-model/devres.rst b/Documentation/driver-model/devres.rst
index 6af41a6a4bb6..84bdb61f27a3 100644
--- a/Documentation/driver-model/devres.rst
+++ b/Documentation/driver-model/devres.rst
@@ -268,6 +268,12 @@ DMA
 DRM
   devm_drm_dev_init()
 
+DVB
+  devm_dvb_dmx_init()
+  devm_dvb_dmxdev_init()
+  devm_dvb_register_adapter()
+  devm_dvb_register_frontend()
+
 GPIO
   devm_gpiod_get()
   devm_gpiod_get_index()
diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c
index f14a872d1268..f38b65d1b430 100644
--- a/drivers/media/dvb-core/dmxdev.c
+++ b/drivers/media/dvb-core/dmxdev.c
@@ -1444,6 +1444,19 @@ int dvb_dmxdev_init(struct dmxdev *dmxdev, struct dvb_adapter *dvb_adapter)
 
 EXPORT_SYMBOL(dvb_dmxdev_init);
 
+static void dmxdev_release(void *dmxdev)
+{
+	dvb_dmxdev_release(dmxdev);
+}
+
+int devm_dvb_dmxdev_init(struct device *dev, struct dmxdev *dmxdev,
+		struct dvb_adapter *dvb_adapter)
+{
+	int rc = dvb_dmxdev_init(dmxdev, dvb_adapter);
+	return rc ? : devm_add_action_or_reset(dev, dmxdev_release, dmxdev);
+}
+EXPORT_SYMBOL(devm_dvb_dmxdev_init);
+
 void dvb_dmxdev_release(struct dmxdev *dmxdev)
 {
 	dmxdev->exit = 1;
diff --git a/drivers/media/dvb-core/dvb_demux.c b/drivers/media/dvb-core/dvb_demux.c
index 39a2c6ccf31d..55b9675b99c5 100644
--- a/drivers/media/dvb-core/dvb_demux.c
+++ b/drivers/media/dvb-core/dvb_demux.c
@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/crc32.h>
 #include <linux/uaccess.h>
+#include <linux/device.h>
 #include <asm/div64.h>
 
 #include <media/dvb_demux.h>
@@ -1317,6 +1318,18 @@ int dvb_dmx_init(struct dvb_demux *dvbdemux)
 
 EXPORT_SYMBOL(dvb_dmx_init);
 
+static void dmx_release(void *dvbdemux)
+{
+	dvb_dmx_release(dvbdemux);
+}
+
+int devm_dvb_dmx_init(struct device *dev, struct dvb_demux *dvbdemux)
+{
+	int rc = dvb_dmx_init(dvbdemux);
+	return rc ? : devm_add_action_or_reset(dev, dmx_release, dvbdemux);
+}
+EXPORT_SYMBOL(devm_dvb_dmx_init);
+
 void dvb_dmx_release(struct dvb_demux *dvbdemux)
 {
 	vfree(dvbdemux->cnt_storage);
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 209186c5cd9b..4a281cd8c064 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -3007,6 +3007,19 @@ int dvb_register_frontend(struct dvb_adapter *dvb,
 }
 EXPORT_SYMBOL(dvb_register_frontend);
 
+static void unregister_frontend(void *fe)
+{
+	dvb_unregister_frontend(fe);
+}
+
+int devm_dvb_register_frontend(struct device *dev,
+		struct dvb_adapter *dvb, struct dvb_frontend *fe)
+{
+	int rc = dvb_register_frontend(dvb, fe);
+	return rc ? : devm_add_action_or_reset(dev, unregister_frontend, fe);
+}
+EXPORT_SYMBOL(devm_dvb_register_frontend);
+
 int dvb_unregister_frontend(struct dvb_frontend *fe)
 {
 	struct dvb_frontend_private *fepriv = fe->frontend_priv;
diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c
index a3393cd4e584..0fc8dbf65045 100644
--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -885,6 +885,18 @@ int dvb_register_adapter(struct dvb_adapter *adap, const char *name,
 }
 EXPORT_SYMBOL(dvb_register_adapter);
 
+static void unreg_adapter(void *adap)
+{
+	dvb_unregister_adapter(adap);
+}
+
+int devm_dvb_register_adapter(struct device *dev, struct dvb_adapter *adap,
+		const char *name, struct module *module, short *adapter_nums)
+{
+	int rc = dvb_register_adapter(adap, name, module, dev, adapter_nums);
+	return rc < 0 ? rc : devm_add_action_or_reset(dev, unreg_adapter, adap);
+}
+EXPORT_SYMBOL(devm_dvb_register_adapter);
 
 int dvb_unregister_adapter(struct dvb_adapter *adap)
 {
diff --git a/include/media/dmxdev.h b/include/media/dmxdev.h
index baafa3b8aca4..0300d829aeea 100644
--- a/include/media/dmxdev.h
+++ b/include/media/dmxdev.h
@@ -204,6 +204,9 @@ struct dmxdev {
  */
 int dvb_dmxdev_init(struct dmxdev *dmxdev, struct dvb_adapter *adap);
 
+int devm_dvb_dmxdev_init(struct device *dev, struct dmxdev *dmxdev,
+		struct dvb_adapter *dvb_adapter);
+
 /**
  * dvb_dmxdev_release - releases a digital TV demux and unregisters it.
  *
diff --git a/include/media/dvb_demux.h b/include/media/dvb_demux.h
index 3b6aeca7a49e..95fe901076d7 100644
--- a/include/media/dvb_demux.h
+++ b/include/media/dvb_demux.h
@@ -266,6 +266,8 @@ struct dvb_demux {
  */
 int dvb_dmx_init(struct dvb_demux *demux);
 
+int devm_dvb_dmx_init(struct device *dev, struct dvb_demux *demux);
+
 /**
  * dvb_dmx_release - releases a digital TV demux internal buffers.
  *
diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h
index f05cd7b94a2c..56dbaf3cc7a9 100644
--- a/include/media/dvb_frontend.h
+++ b/include/media/dvb_frontend.h
@@ -713,6 +713,9 @@ struct dvb_frontend {
 int dvb_register_frontend(struct dvb_adapter *dvb,
 				 struct dvb_frontend *fe);
 
+int devm_dvb_register_frontend(struct device *dev,
+		struct dvb_adapter *dvb, struct dvb_frontend *fe);
+
 /**
  * dvb_unregister_frontend() - Unregisters a DVB frontend
  *
diff --git a/include/media/dvbdev.h b/include/media/dvbdev.h
index 551325858de3..32f8d1626319 100644
--- a/include/media/dvbdev.h
+++ b/include/media/dvbdev.h
@@ -202,6 +202,9 @@ int dvb_register_adapter(struct dvb_adapter *adap, const char *name,
 			 struct module *module, struct device *device,
 			 short *adapter_nums);
 
+int devm_dvb_register_adapter(struct device *dev, struct dvb_adapter *adap,
+		const char *name, struct module *module, short *adapter_nums);
+
 /**
  * dvb_unregister_adapter - Unregisters a DVB adapter
  *
-- 
2.17.1

Re: [PATCH v3] media: dvb: Provide 4 devm variants

[Ezequiel Garcia]

Hi Marc,

Thanks for your patch.

On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
> Provide devm variants for automatic resource release on device removal.
> Makes error-handling in probe() simpler, thus less error-prone.
> Once all resources are devmanaged, remove() is no longer needed.
> 

I think it would be better to add this API as part of a series
that also uses it.

Regards,
Eze

Re: [PATCH v3] media: dvb: Provide 4 devm variants

[Marc Gonzalez]

On 21/07/2019 17:02, Ezequiel Garcia wrote:

> On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
>
>> Provide devm variants for automatic resource release on device removal.
>> Makes error-handling in probe() simpler, thus less error-prone.
>> Once all resources are devmanaged, remove() is no longer needed.
> 
> I think it would be better to add this API as part of a series
> that also uses it.

I have an outstanding RFC for a new driver:

	https://patchwork.kernel.org/patch/11040435/

Locally, I've updated the probe function to use the proposed devm functions.

I was mainly hoping to get initial feedback from the maintainers.
1) See if they're OK with devm APIs
2) See if they're OK with the way I implemented devm APIs
3) See what's missing to get an Ack

static int tsif_probe(struct platform_device *pdev)
{
	int err, virq;
	struct tsif *tsif;
	struct resource *res;
	struct dvb_frontend *fe;
	struct dvb_adapter *adap;
	struct device *dev = &pdev->dev;
	short num = DVB_UNSET;

	fe = dvb_get_demod_fe(dev->of_node);
	if (!fe)
		return -ENXIO;

	tsif = devm_kzalloc(dev, sizeof(*tsif), GFP_KERNEL);
	if (!tsif)
		return -ENOMEM;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsif0");
	tsif->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(tsif->base))
		return PTR_ERR(tsif->base);

	virq = platform_get_irq_byname(pdev, "tsif0");
	err = devm_request_irq(dev, virq, tsif_isr, IRQF_SHARED, "tsif", tsif);
	if (err)
		return err;

	tsif->clk = devm_clk_get(dev, "iface");
	if (IS_ERR(tsif->clk))
		return PTR_ERR(tsif->clk);

	err = devm_clk_prepare_enable(dev, tsif->clk);
	if (err)
		return err;

	adap = &tsif->adapter;
	err = devm_dvb_register_adapter(dev, adap, "tsif", THIS_MODULE, &num);
	if (err) return err;

	/* Not sure the diff between filter and feed? */
	tsif->demux.filternum = 16; /*** Dunno what to put here ***/
	tsif->demux.feednum = 16;	/*** Dunno what to put here ***/
	tsif->demux.start_feed = noop;
	tsif->demux.stop_feed = noop;
	err = devm_dvb_dmx_init(dev, &tsif->demux);
	if (err) return err;

	/* What relation to dvb_demux.filternum??? */
	/* Do I need this object?? */
	tsif->dmxdev.filternum = 16;
	tsif->dmxdev.demux = &tsif->demux.dmx;
	err = devm_dvb_dmxdev_init(dev, &tsif->dmxdev, adap);
	if (err) return err;

	err = devm_dvb_register_frontend(dev, adap, fe);
	if (err) return err;

	writel_relaxed(TSIF_START + ENABLE_IRQ, tsif->base + TSIF_STS_CTL);
	devm_add_action(dev, stop_tsif, tsif);
	INIT_WORK(&tsif->work, handle_pkt);

	return 0;
}

Re: [PATCH v3] media: dvb: Provide 4 devm variants

[Sean Young]

On Mon, Jul 22, 2019 at 10:13:56AM +0200, Marc Gonzalez wrote:
> On 21/07/2019 17:02, Ezequiel Garcia wrote:
> 
> > On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
> >
> >> Provide devm variants for automatic resource release on device removal.
> >> Makes error-handling in probe() simpler, thus less error-prone.
> >> Once all resources are devmanaged, remove() is no longer needed.
> > 
> > I think it would be better to add this API as part of a series
> > that also uses it.
> 
> I have an outstanding RFC for a new driver:
> 
> 	https://patchwork.kernel.org/patch/11040435/
> 
> Locally, I've updated the probe function to use the proposed devm functions.
> 
> I was mainly hoping to get initial feedback from the maintainers.
> 1) See if they're OK with devm APIs

devm_ has some lifetime issues, wrt to disconnect. However, for a platform
device it is fine.

> 2) See if they're OK with the way I implemented devm APIs

Looks good to me.

> 3) See what's missing to get an Ack

Please submit both this patch and a the driver as a series.

Thanks,

Sean

> 
> static int tsif_probe(struct platform_device *pdev)
> {
> 	int err, virq;
> 	struct tsif *tsif;
> 	struct resource *res;
> 	struct dvb_frontend *fe;
> 	struct dvb_adapter *adap;
> 	struct device *dev = &pdev->dev;
> 	short num = DVB_UNSET;
> 
> 	fe = dvb_get_demod_fe(dev->of_node);
> 	if (!fe)
> 		return -ENXIO;
> 
> 	tsif = devm_kzalloc(dev, sizeof(*tsif), GFP_KERNEL);
> 	if (!tsif)
> 		return -ENOMEM;
> 
> 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsif0");
> 	tsif->base = devm_ioremap_resource(dev, res);
> 	if (IS_ERR(tsif->base))
> 		return PTR_ERR(tsif->base);
> 
> 	virq = platform_get_irq_byname(pdev, "tsif0");
> 	err = devm_request_irq(dev, virq, tsif_isr, IRQF_SHARED, "tsif", tsif);
> 	if (err)
> 		return err;
> 
> 	tsif->clk = devm_clk_get(dev, "iface");
> 	if (IS_ERR(tsif->clk))
> 		return PTR_ERR(tsif->clk);
> 
> 	err = devm_clk_prepare_enable(dev, tsif->clk);
> 	if (err)
> 		return err;
> 
> 	adap = &tsif->adapter;
> 	err = devm_dvb_register_adapter(dev, adap, "tsif", THIS_MODULE, &num);
> 	if (err) return err;
> 
> 	/* Not sure the diff between filter and feed? */
> 	tsif->demux.filternum = 16; /*** Dunno what to put here ***/
> 	tsif->demux.feednum = 16;	/*** Dunno what to put here ***/
> 	tsif->demux.start_feed = noop;
> 	tsif->demux.stop_feed = noop;
> 	err = devm_dvb_dmx_init(dev, &tsif->demux);
> 	if (err) return err;
> 
> 	/* What relation to dvb_demux.filternum??? */
> 	/* Do I need this object?? */
> 	tsif->dmxdev.filternum = 16;
> 	tsif->dmxdev.demux = &tsif->demux.dmx;
> 	err = devm_dvb_dmxdev_init(dev, &tsif->dmxdev, adap);
> 	if (err) return err;
> 
> 	err = devm_dvb_register_frontend(dev, adap, fe);
> 	if (err) return err;
> 
> 	writel_relaxed(TSIF_START + ENABLE_IRQ, tsif->base + TSIF_STS_CTL);
> 	devm_add_action(dev, stop_tsif, tsif);
> 	INIT_WORK(&tsif->work, handle_pkt);
> 
> 	return 0;
> }