[PATCH 0/2] HID special drivers converted to devres API

[PATCH 0/2] HID special drivers converted to devres API

[Benjamin Tissoires]

Hi Jiri,

It's been a long time since I told you that I was about to work on the devres API...
So here are the first patches.

My deductions are that it is safe to run devm_* functions within the hid subsystem.
With this, we can simplify a little the error path of some drivers. The gain
is more visible for hid-multitouch as the function mt_free_input_name() can
be entirely dropped.

Cheers,
Benjamin

Benjamin Tissoires (2):
  HID: trivial devm conversion for special hid drivers
  HID: multitouch: devm conversion

 drivers/hid/hid-a4tech.c     | 23 +++-----------
 drivers/hid/hid-apple.c      | 16 ++--------
 drivers/hid/hid-magicmouse.c | 17 ++---------
 drivers/hid/hid-multitouch.c | 71 ++++++++++++++------------------------------
 drivers/hid/hid-sony.c       |  9 ++----
 drivers/hid/hid-zydacron.c   | 19 ++----------
 6 files changed, 39 insertions(+), 116 deletions(-)

-- 
1.8.3.1

[PATCH 1/2] HID: trivial devm conversion for special hid drivers

[Benjamin Tissoires]

It is safe to use devres allocation within the hid subsystem:
- the devres release is called _after_ the call to .remove(), meaning
  that no freed pointers will exists while removing the device
- if a .probe() fails, devres releases all the allocated ressources
  before going to the next driver: there will not be ghost ressources
  attached to a hid device if several drivers are probed.

Given that, we can clean up a little some of the HID drivers. These ones
are trivial:
- there is only one kzalloc in the driver
- the .remove() callback contains only one kfree on top of hid_hw_stop()
- the error path in the probe is easy enough to be manually checked

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/hid/hid-a4tech.c     | 23 ++++-------------------
 drivers/hid/hid-apple.c      | 16 +++-------------
 drivers/hid/hid-magicmouse.c | 17 +++--------------
 drivers/hid/hid-sony.c       |  9 +++------
 drivers/hid/hid-zydacron.c   | 19 +++----------------
 5 files changed, 16 insertions(+), 68 deletions(-)

diff --git a/drivers/hid/hid-a4tech.c b/drivers/hid/hid-a4tech.c
index 7c5507e..8d4e999 100644
--- a/drivers/hid/hid-a4tech.c
+++ b/drivers/hid/hid-a4tech.c
@@ -90,11 +90,10 @@ static int a4_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	struct a4tech_sc *a4;
 	int ret;
 
-	a4 = kzalloc(sizeof(*a4), GFP_KERNEL);
+	a4 = devm_kzalloc(&hdev->dev, sizeof(*a4), GFP_KERNEL);
 	if (a4 == NULL) {
 		hid_err(hdev, "can't alloc device descriptor\n");
-		ret = -ENOMEM;
-		goto err_free;
+		return -ENOMEM;
 	}
 
 	a4->quirks = id->driver_data;
@@ -104,29 +103,16 @@ static int a4_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "parse failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
-	if (ret) {
+	if (ret)
 		hid_err(hdev, "hw start failed\n");
-		goto err_free;
-	}
 
-	return 0;
-err_free:
-	kfree(a4);
 	return ret;
 }
 
-static void a4_remove(struct hid_device *hdev)
-{
-	struct a4tech_sc *a4 = hid_get_drvdata(hdev);
-
-	hid_hw_stop(hdev);
-	kfree(a4);
-}
-
 static const struct hid_device_id a4_devices[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_WCP32PU),
 		.driver_data = A4_2WHEEL_MOUSE_HACK_7 },
@@ -144,7 +130,6 @@ static struct hid_driver a4_driver = {
 	.input_mapped = a4_input_mapped,
 	.event = a4_event,
 	.probe = a4_probe,
-	.remove = a4_remove,
 };
 module_hid_driver(a4_driver);
 
diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
index c7710b5..881cf7b 100644
--- a/drivers/hid/hid-apple.c
+++ b/drivers/hid/hid-apple.c
@@ -349,7 +349,7 @@ static int apple_probe(struct hid_device *hdev,
 	unsigned int connect_mask = HID_CONNECT_DEFAULT;
 	int ret;
 
-	asc = kzalloc(sizeof(*asc), GFP_KERNEL);
+	asc = devm_kzalloc(&hdev->dev, sizeof(*asc), GFP_KERNEL);
 	if (asc == NULL) {
 		hid_err(hdev, "can't alloc apple descriptor\n");
 		return -ENOMEM;
@@ -362,7 +362,7 @@ static int apple_probe(struct hid_device *hdev,
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "parse failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	if (quirks & APPLE_HIDDEV)
@@ -373,19 +373,10 @@ static int apple_probe(struct hid_device *hdev,
 	ret = hid_hw_start(hdev, connect_mask);
 	if (ret) {
 		hid_err(hdev, "hw start failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	return 0;
-err_free:
-	kfree(asc);
-	return ret;
-}
-
-static void apple_remove(struct hid_device *hdev)
-{
-	hid_hw_stop(hdev);
-	kfree(hid_get_drvdata(hdev));
 }
 
 static const struct hid_device_id apple_devices[] = {
@@ -551,7 +542,6 @@ static struct hid_driver apple_driver = {
 	.id_table = apple_devices,
 	.report_fixup = apple_report_fixup,
 	.probe = apple_probe,
-	.remove = apple_remove,
 	.event = apple_event,
 	.input_mapping = apple_input_mapping,
 	.input_mapped = apple_input_mapped,
diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index 5bc3734..d393eb7 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -484,7 +484,7 @@ static int magicmouse_probe(struct hid_device *hdev,
 	struct hid_report *report;
 	int ret;
 
-	msc = kzalloc(sizeof(*msc), GFP_KERNEL);
+	msc = devm_kzalloc(&hdev->dev, sizeof(*msc), GFP_KERNEL);
 	if (msc == NULL) {
 		hid_err(hdev, "can't alloc magicmouse descriptor\n");
 		return -ENOMEM;
@@ -498,13 +498,13 @@ static int magicmouse_probe(struct hid_device *hdev,
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "magicmouse hid parse failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret) {
 		hid_err(hdev, "magicmouse hw start failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	if (!msc->input) {
@@ -548,19 +548,9 @@ static int magicmouse_probe(struct hid_device *hdev,
 	return 0;
 err_stop_hw:
 	hid_hw_stop(hdev);
-err_free:
-	kfree(msc);
 	return ret;
 }
 
-static void magicmouse_remove(struct hid_device *hdev)
-{
-	struct magicmouse_sc *msc = hid_get_drvdata(hdev);
-
-	hid_hw_stop(hdev);
-	kfree(msc);
-}
-
 static const struct hid_device_id magic_mice[] = {
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_APPLE,
 		USB_DEVICE_ID_APPLE_MAGICMOUSE), .driver_data = 0 },
@@ -574,7 +564,6 @@ static struct hid_driver magicmouse_driver = {
 	.name = "magicmouse",
 	.id_table = magic_mice,
 	.probe = magicmouse_probe,
-	.remove = magicmouse_remove,
 	.raw_event = magicmouse_raw_event,
 	.input_mapping = magicmouse_input_mapping,
 	.input_configured = magicmouse_input_configured,
diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 87fbe29..30dbb6b 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -624,7 +624,7 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	struct sony_sc *sc;
 	unsigned int connect_mask = HID_CONNECT_DEFAULT;
 
-	sc = kzalloc(sizeof(*sc), GFP_KERNEL);
+	sc = devm_kzalloc(&hdev->dev, sizeof(*sc), GFP_KERNEL);
 	if (sc == NULL) {
 		hid_err(hdev, "can't alloc sony descriptor\n");
 		return -ENOMEM;
@@ -636,7 +636,7 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "parse failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	if (sc->quirks & VAIO_RDESC_CONSTANT)
@@ -649,7 +649,7 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	ret = hid_hw_start(hdev, connect_mask);
 	if (ret) {
 		hid_err(hdev, "hw start failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	if (sc->quirks & SIXAXIS_CONTROLLER_USB) {
@@ -669,8 +669,6 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	return 0;
 err_stop:
 	hid_hw_stop(hdev);
-err_free:
-	kfree(sc);
 	return ret;
 }
 
@@ -682,7 +680,6 @@ static void sony_remove(struct hid_device *hdev)
 		buzz_remove(hdev);
 
 	hid_hw_stop(hdev);
-	kfree(sc);
 }
 
 static const struct hid_device_id sony_devices[] = {
diff --git a/drivers/hid/hid-zydacron.c b/drivers/hid/hid-zydacron.c
index e4cddec..1a660bd 100644
--- a/drivers/hid/hid-zydacron.c
+++ b/drivers/hid/hid-zydacron.c
@@ -169,7 +169,7 @@ static int zc_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	int ret;
 	struct zc_device *zc;
 
-	zc = kzalloc(sizeof(*zc), GFP_KERNEL);
+	zc = devm_kzalloc(&hdev->dev, sizeof(*zc), GFP_KERNEL);
 	if (zc == NULL) {
 		hid_err(hdev, "can't alloc descriptor\n");
 		return -ENOMEM;
@@ -180,28 +180,16 @@ static int zc_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "parse failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret) {
 		hid_err(hdev, "hw start failed\n");
-		goto err_free;
+		return ret;
 	}
 
 	return 0;
-err_free:
-	kfree(zc);
-
-	return ret;
-}
-
-static void zc_remove(struct hid_device *hdev)
-{
-	struct zc_device *zc = hid_get_drvdata(hdev);
-
-	hid_hw_stop(hdev);
-	kfree(zc);
 }
 
 static const struct hid_device_id zc_devices[] = {
@@ -217,7 +205,6 @@ static struct hid_driver zc_driver = {
 	.input_mapping = zc_input_mapping,
 	.raw_event = zc_raw_event,
 	.probe = zc_probe,
-	.remove = zc_remove,
 };
 module_hid_driver(zc_driver);
 
-- 
1.8.3.1

Re: [PATCH 1/2] HID: trivial devm conversion for special hid drivers

[Andy Shevchenko]

On Wed, Jul 24, 2013 at 6:29 PM, Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
> It is safe to use devres allocation within the hid subsystem:
> - the devres release is called _after_ the call to .remove(), meaning
>   that no freed pointers will exists while removing the device
> - if a .probe() fails, devres releases all the allocated ressources
>   before going to the next driver: there will not be ghost ressources
>   attached to a hid device if several drivers are probed.
>
> Given that, we can clean up a little some of the HID drivers. These ones
> are trivial:
> - there is only one kzalloc in the driver
> - the .remove() callback contains only one kfree on top of hid_hw_stop()
> - the error path in the probe is easy enough to be manually checked

Thanks for the patch! I'm sorry I didn't find time to do what I was
talking about last time.

Few comments below.

> --- a/drivers/hid/hid-a4tech.c
> +++ b/drivers/hid/hid-a4tech.c

> @@ -104,29 +103,16 @@ static int a4_probe(struct hid_device *hdev, const struct hid_device_id *id)
>         ret = hid_parse(hdev);
>         if (ret) {
>                 hid_err(hdev, "parse failed\n");
> -               goto err_free;
> +               return ret;
>         }
>
>         ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
> -       if (ret) {
> +       if (ret)
>                 hid_err(hdev, "hw start failed\n");
> -               goto err_free;
> -       }
>
> -       return 0;

Isn't it better to leave explicit return 0? I think it would be fool
proof in case someone wants to add anything in the middle.

> -err_free:
> -       kfree(a4);
>         return ret;
>  }

> -static void a4_remove(struct hid_device *hdev)
> -{
> -       struct a4tech_sc *a4 = hid_get_drvdata(hdev);
> -
> -       hid_hw_stop(hdev);

Is it safe to remove this call?
This question is the same for all patched drivers.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/2] HID: trivial devm conversion for special hid drivers

[Benjamin Tissoires]

On Wed, Jul 24, 2013 at 5:37 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Wed, Jul 24, 2013 at 6:29 PM, Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
>> It is safe to use devres allocation within the hid subsystem:
>> - the devres release is called _after_ the call to .remove(), meaning
>>   that no freed pointers will exists while removing the device
>> - if a .probe() fails, devres releases all the allocated ressources
>>   before going to the next driver: there will not be ghost ressources
>>   attached to a hid device if several drivers are probed.
>>
>> Given that, we can clean up a little some of the HID drivers. These ones
>> are trivial:
>> - there is only one kzalloc in the driver
>> - the .remove() callback contains only one kfree on top of hid_hw_stop()
>> - the error path in the probe is easy enough to be manually checked
>
> Thanks for the patch! I'm sorry I didn't find time to do what I was
> talking about last time.

no problems :)

>
> Few comments below.
>
>> --- a/drivers/hid/hid-a4tech.c
>> +++ b/drivers/hid/hid-a4tech.c
>
>> @@ -104,29 +103,16 @@ static int a4_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         ret = hid_parse(hdev);
>>         if (ret) {
>>                 hid_err(hdev, "parse failed\n");
>> -               goto err_free;
>> +               return ret;
>>         }
>>
>>         ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
>> -       if (ret) {
>> +       if (ret)
>>                 hid_err(hdev, "hw start failed\n");
>> -               goto err_free;
>> -       }
>>
>> -       return 0;
>
> Isn't it better to leave explicit return 0? I think it would be fool
> proof in case someone wants to add anything in the middle.

yes, it might be. At least that's what I've done with the other drivers...

>
>> -err_free:
>> -       kfree(a4);
>>         return ret;
>>  }
>
>> -static void a4_remove(struct hid_device *hdev)
>> -{
>> -       struct a4tech_sc *a4 = hid_get_drvdata(hdev);
>> -
>> -       hid_hw_stop(hdev);
>
> Is it safe to remove this call?
> This question is the same for all patched drivers.

It is. Once this call is removed, we use the in-core remove path,
which calls hid_hw_stop().

Thanks for the review.

Cheers,
Benjamin

[PATCH 2/2] HID: multitouch: devm conversion

[Benjamin Tissoires]

HID special drivers can use safely the devres API.
Use it to remove 25 lines of code and to clean up a little the error paths.

Besides the pur kzalloc -> devm_kzalloc conversions, I changed the
place of the allocation of the new name. Doing this right in
mt_input_configured() removes the kstrdup call which was not very helpful
and the new way is simpler to understand (and to debug).

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/hid/hid-multitouch.c | 71 ++++++++++++++------------------------------
 1 file changed, 23 insertions(+), 48 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index cb0e361..0fe00e2 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -261,17 +261,6 @@ static struct mt_class mt_classes[] = {
 	{ }
 };
 
-static void mt_free_input_name(struct hid_input *hi)
-{
-	struct hid_device *hdev = hi->report->device;
-	const char *name = hi->input->name;
-
-	if (name != hdev->name) {
-		hi->input->name = hdev->name;
-		kfree(name);
-	}
-}
-
 static ssize_t mt_show_quirks(struct device *dev,
 			   struct device_attribute *attr,
 			   char *buf)
@@ -415,13 +404,6 @@ static void mt_pen_report(struct hid_device *hid, struct hid_report *report)
 static void mt_pen_input_configured(struct hid_device *hdev,
 					struct hid_input *hi)
 {
-	char *name = kzalloc(strlen(hi->input->name) + 5, GFP_KERNEL);
-	if (name) {
-		sprintf(name, "%s Pen", hi->input->name);
-		mt_free_input_name(hi);
-		hi->input->name = name;
-	}
-
 	/* force BTN_STYLUS to allow tablet matching in udev */
 	__set_bit(BTN_STYLUS, hi->input->keybit);
 }
@@ -928,16 +910,26 @@ static void mt_post_parse(struct mt_device *td)
 static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
-	char *name = kstrdup(hdev->name, GFP_KERNEL);
-
-	if (name)
-		hi->input->name = name;
+	char *name;
+	const char *suffix = NULL;
 
 	if (hi->report->id == td->mt_report_id)
 		mt_touch_input_configured(hdev, hi);
 
-	if (hi->report->id == td->pen_report_id)
+	if (hi->report->field[0]->physical == HID_DG_STYLUS) {
+		suffix = "Pen";
 		mt_pen_input_configured(hdev, hi);
+	}
+
+	if (suffix) {
+		name = devm_kzalloc(&hi->input->dev,
+				    strlen(hdev->name) + strlen(suffix) + 2,
+				    GFP_KERNEL);
+		if (name) {
+			sprintf(name, "%s %s", hdev->name, suffix);
+			hi->input->name = name;
+		}
+	}
 }
 
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
@@ -945,7 +937,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	int ret, i;
 	struct mt_device *td;
 	struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
-	struct hid_input *hi;
 
 	for (i = 0; mt_classes[i].name ; i++) {
 		if (id->driver_data == mt_classes[i].name) {
@@ -967,7 +958,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
 	hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
 
-	td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
+	td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
 	if (!td) {
 		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
 		return -ENOMEM;
@@ -980,11 +971,11 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	td->pen_report_id = -1;
 	hid_set_drvdata(hdev, td);
 
-	td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
+	td->fields = devm_kzalloc(&hdev->dev, sizeof(struct mt_fields),
+				  GFP_KERNEL);
 	if (!td->fields) {
 		dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
-		ret = -ENOMEM;
-		goto fail;
+		return -ENOMEM;
 	}
 
 	if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
@@ -992,29 +983,22 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	ret = hid_parse(hdev);
 	if (ret != 0)
-		goto fail;
+		return ret;
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret)
-		goto hid_fail;
+		return ret;
 
 	ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
 
 	mt_set_maxcontacts(hdev);
 	mt_set_input_mode(hdev);
 
-	kfree(td->fields);
+	/* release .fields memory as it is not used anymore */
+	devm_kfree(&hdev->dev, td->fields);
 	td->fields = NULL;
 
 	return 0;
-
-hid_fail:
-	list_for_each_entry(hi, &hdev->inputs, list)
-		mt_free_input_name(hi);
-fail:
-	kfree(td->fields);
-	kfree(td);
-	return ret;
 }
 
 #ifdef CONFIG_PM
@@ -1039,17 +1023,8 @@ static int mt_resume(struct hid_device *hdev)
 
 static void mt_remove(struct hid_device *hdev)
 {
-	struct mt_device *td = hid_get_drvdata(hdev);
-	struct hid_input *hi;
-
 	sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
-	list_for_each_entry(hi, &hdev->inputs, list)
-		mt_free_input_name(hi);
-
 	hid_hw_stop(hdev);
-
-	kfree(td);
-	hid_set_drvdata(hdev, NULL);
 }
 
 static const struct hid_device_id mt_devices[] = {
-- 
1.8.3.1

Re: [PATCH 2/2] HID: multitouch: devm conversion

[Andy Shevchenko]

On Wed, Jul 24, 2013 at 6:29 PM, Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
> HID special drivers can use safely the devres API.
> Use it to remove 25 lines of code and to clean up a little the error paths.
>
> Besides the pur kzalloc -> devm_kzalloc conversions, I changed the

Typo 'pur' -> 'put'

> place of the allocation of the new name. Doing this right in
> mt_input_configured() removes the kstrdup call which was not very helpful
> and the new way is simpler to understand (and to debug).

Thanks for the patch! I'm sorry I didn't find time to do this by myself.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
>  drivers/hid/hid-multitouch.c | 71 ++++++++++++++------------------------------
>  1 file changed, 23 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index cb0e361..0fe00e2 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -261,17 +261,6 @@ static struct mt_class mt_classes[] = {
>         { }
>  };
>
> -static void mt_free_input_name(struct hid_input *hi)
> -{
> -       struct hid_device *hdev = hi->report->device;
> -       const char *name = hi->input->name;
> -
> -       if (name != hdev->name) {
> -               hi->input->name = hdev->name;
> -               kfree(name);
> -       }
> -}
> -
>  static ssize_t mt_show_quirks(struct device *dev,
>                            struct device_attribute *attr,
>                            char *buf)
> @@ -415,13 +404,6 @@ static void mt_pen_report(struct hid_device *hid, struct hid_report *report)
>  static void mt_pen_input_configured(struct hid_device *hdev,
>                                         struct hid_input *hi)
>  {
> -       char *name = kzalloc(strlen(hi->input->name) + 5, GFP_KERNEL);
> -       if (name) {
> -               sprintf(name, "%s Pen", hi->input->name);
> -               mt_free_input_name(hi);
> -               hi->input->name = name;
> -       }
> -
>         /* force BTN_STYLUS to allow tablet matching in udev */
>         __set_bit(BTN_STYLUS, hi->input->keybit);
>  }
> @@ -928,16 +910,26 @@ static void mt_post_parse(struct mt_device *td)
>  static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
>  {
>         struct mt_device *td = hid_get_drvdata(hdev);
> -       char *name = kstrdup(hdev->name, GFP_KERNEL);
> -
> -       if (name)
> -               hi->input->name = name;
> +       char *name;
> +       const char *suffix = NULL;
>
>         if (hi->report->id == td->mt_report_id)
>                 mt_touch_input_configured(hdev, hi);
>
> -       if (hi->report->id == td->pen_report_id)
> +       if (hi->report->field[0]->physical == HID_DG_STYLUS) {
> +               suffix = "Pen";
>                 mt_pen_input_configured(hdev, hi);
> +       }
> +
> +       if (suffix) {
> +               name = devm_kzalloc(&hi->input->dev,
> +                                   strlen(hdev->name) + strlen(suffix) + 2,
> +                                   GFP_KERNEL);
> +               if (name) {
> +                       sprintf(name, "%s %s", hdev->name, suffix);
> +                       hi->input->name = name;
> +               }
> +       }
>  }
>
>  static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
> @@ -945,7 +937,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>         int ret, i;
>         struct mt_device *td;
>         struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
> -       struct hid_input *hi;
>
>         for (i = 0; mt_classes[i].name ; i++) {
>                 if (id->driver_data == mt_classes[i].name) {
> @@ -967,7 +958,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>         hdev->quirks |= HID_QUIRK_MULTI_INPUT;
>         hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
>
> -       td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
> +       td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
>         if (!td) {
>                 dev_err(&hdev->dev, "cannot allocate multitouch data\n");
>                 return -ENOMEM;
> @@ -980,11 +971,11 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>         td->pen_report_id = -1;
>         hid_set_drvdata(hdev, td);
>
> -       td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
> +       td->fields = devm_kzalloc(&hdev->dev, sizeof(struct mt_fields),
> +                                 GFP_KERNEL);
>         if (!td->fields) {
>                 dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
> -               ret = -ENOMEM;
> -               goto fail;
> +               return -ENOMEM;
>         }
>
>         if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
> @@ -992,29 +983,22 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>
>         ret = hid_parse(hdev);
>         if (ret != 0)
> -               goto fail;
> +               return ret;
>
>         ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
>         if (ret)
> -               goto hid_fail;
> +               return ret;
>
>         ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
>
>         mt_set_maxcontacts(hdev);
>         mt_set_input_mode(hdev);
>
> -       kfree(td->fields);
> +       /* release .fields memory as it is not used anymore */
> +       devm_kfree(&hdev->dev, td->fields);
>         td->fields = NULL;
>
>         return 0;
> -
> -hid_fail:
> -       list_for_each_entry(hi, &hdev->inputs, list)
> -               mt_free_input_name(hi);
> -fail:
> -       kfree(td->fields);
> -       kfree(td);
> -       return ret;
>  }
>
>  #ifdef CONFIG_PM
> @@ -1039,17 +1023,8 @@ static int mt_resume(struct hid_device *hdev)
>
>  static void mt_remove(struct hid_device *hdev)
>  {
> -       struct mt_device *td = hid_get_drvdata(hdev);
> -       struct hid_input *hi;
> -
>         sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
> -       list_for_each_entry(hi, &hdev->inputs, list)
> -               mt_free_input_name(hi);
> -
>         hid_hw_stop(hdev);
> -
> -       kfree(td);
> -       hid_set_drvdata(hdev, NULL);
>  }
>
>  static const struct hid_device_id mt_devices[] = {
> --
> 1.8.3.1
>



--
With Best Regards,
Andy Shevchenko

Re: [PATCH 2/2] HID: multitouch: devm conversion

[Benjamin Tissoires]

On Wed, Jul 24, 2013 at 5:44 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Wed, Jul 24, 2013 at 6:29 PM, Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
>> HID special drivers can use safely the devres API.
>> Use it to remove 25 lines of code and to clean up a little the error paths.
>>
>> Besides the pur kzalloc -> devm_kzalloc conversions, I changed the
>
> Typo 'pur' -> 'put'

oops, sorry. I'll use "basic" in the next version.

>
>> place of the allocation of the new name. Doing this right in
>> mt_input_configured() removes the kstrdup call which was not very helpful
>> and the new way is simpler to understand (and to debug).
>
> Thanks for the patch! I'm sorry I didn't find time to do this by myself.
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Thanks!

Cheers,
Benjamin

>
>>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>> ---
>>  drivers/hid/hid-multitouch.c | 71 ++++++++++++++------------------------------
>>  1 file changed, 23 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
>> index cb0e361..0fe00e2 100644
>> --- a/drivers/hid/hid-multitouch.c
>> +++ b/drivers/hid/hid-multitouch.c
>> @@ -261,17 +261,6 @@ static struct mt_class mt_classes[] = {
>>         { }
>>  };
>>
>> -static void mt_free_input_name(struct hid_input *hi)
>> -{
>> -       struct hid_device *hdev = hi->report->device;
>> -       const char *name = hi->input->name;
>> -
>> -       if (name != hdev->name) {
>> -               hi->input->name = hdev->name;
>> -               kfree(name);
>> -       }
>> -}
>> -
>>  static ssize_t mt_show_quirks(struct device *dev,
>>                            struct device_attribute *attr,
>>                            char *buf)
>> @@ -415,13 +404,6 @@ static void mt_pen_report(struct hid_device *hid, struct hid_report *report)
>>  static void mt_pen_input_configured(struct hid_device *hdev,
>>                                         struct hid_input *hi)
>>  {
>> -       char *name = kzalloc(strlen(hi->input->name) + 5, GFP_KERNEL);
>> -       if (name) {
>> -               sprintf(name, "%s Pen", hi->input->name);
>> -               mt_free_input_name(hi);
>> -               hi->input->name = name;
>> -       }
>> -
>>         /* force BTN_STYLUS to allow tablet matching in udev */
>>         __set_bit(BTN_STYLUS, hi->input->keybit);
>>  }
>> @@ -928,16 +910,26 @@ static void mt_post_parse(struct mt_device *td)
>>  static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
>>  {
>>         struct mt_device *td = hid_get_drvdata(hdev);
>> -       char *name = kstrdup(hdev->name, GFP_KERNEL);
>> -
>> -       if (name)
>> -               hi->input->name = name;
>> +       char *name;
>> +       const char *suffix = NULL;
>>
>>         if (hi->report->id == td->mt_report_id)
>>                 mt_touch_input_configured(hdev, hi);
>>
>> -       if (hi->report->id == td->pen_report_id)
>> +       if (hi->report->field[0]->physical == HID_DG_STYLUS) {
>> +               suffix = "Pen";
>>                 mt_pen_input_configured(hdev, hi);
>> +       }
>> +
>> +       if (suffix) {
>> +               name = devm_kzalloc(&hi->input->dev,
>> +                                   strlen(hdev->name) + strlen(suffix) + 2,
>> +                                   GFP_KERNEL);
>> +               if (name) {
>> +                       sprintf(name, "%s %s", hdev->name, suffix);
>> +                       hi->input->name = name;
>> +               }
>> +       }
>>  }
>>
>>  static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>> @@ -945,7 +937,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         int ret, i;
>>         struct mt_device *td;
>>         struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
>> -       struct hid_input *hi;
>>
>>         for (i = 0; mt_classes[i].name ; i++) {
>>                 if (id->driver_data == mt_classes[i].name) {
>> @@ -967,7 +958,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         hdev->quirks |= HID_QUIRK_MULTI_INPUT;
>>         hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
>>
>> -       td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
>> +       td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
>>         if (!td) {
>>                 dev_err(&hdev->dev, "cannot allocate multitouch data\n");
>>                 return -ENOMEM;
>> @@ -980,11 +971,11 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         td->pen_report_id = -1;
>>         hid_set_drvdata(hdev, td);
>>
>> -       td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
>> +       td->fields = devm_kzalloc(&hdev->dev, sizeof(struct mt_fields),
>> +                                 GFP_KERNEL);
>>         if (!td->fields) {
>>                 dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
>> -               ret = -ENOMEM;
>> -               goto fail;
>> +               return -ENOMEM;
>>         }
>>
>>         if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
>> @@ -992,29 +983,22 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>
>>         ret = hid_parse(hdev);
>>         if (ret != 0)
>> -               goto fail;
>> +               return ret;
>>
>>         ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
>>         if (ret)
>> -               goto hid_fail;
>> +               return ret;
>>
>>         ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
>>
>>         mt_set_maxcontacts(hdev);
>>         mt_set_input_mode(hdev);
>>
>> -       kfree(td->fields);
>> +       /* release .fields memory as it is not used anymore */
>> +       devm_kfree(&hdev->dev, td->fields);
>>         td->fields = NULL;
>>
>>         return 0;
>> -
>> -hid_fail:
>> -       list_for_each_entry(hi, &hdev->inputs, list)
>> -               mt_free_input_name(hi);
>> -fail:
>> -       kfree(td->fields);
>> -       kfree(td);
>> -       return ret;
>>  }
>>
>>  #ifdef CONFIG_PM
>> @@ -1039,17 +1023,8 @@ static int mt_resume(struct hid_device *hdev)
>>
>>  static void mt_remove(struct hid_device *hdev)
>>  {
>> -       struct mt_device *td = hid_get_drvdata(hdev);
>> -       struct hid_input *hi;
>> -
>>         sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
>> -       list_for_each_entry(hi, &hdev->inputs, list)
>> -               mt_free_input_name(hi);
>> -
>>         hid_hw_stop(hdev);
>> -
>> -       kfree(td);
>> -       hid_set_drvdata(hdev, NULL);
>>  }
>>
>>  static const struct hid_device_id mt_devices[] = {
>> --
>> 1.8.3.1
>>
>
>
>
> --
> With Best Regards,
> Andy Shevchenko