diff mbox series

[v1,14/16] soundwire: Use acpi_dev_for_each_child()

Message ID 5296779.Sb9uPGUboI@kreacher (mailing list archive)
State New, archived
Headers show
Series None | expand

Commit Message

Rafael J. Wysocki June 9, 2022, 2:16 p.m. UTC 
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Instead of walking the list of children of an ACPI device directly,
use acpi_dev_for_each_child() to carry out an action for all of
the given ACPI device's children.

This will help to eliminate the children list head from struct
acpi_device as it is redundant and it is used in questionable ways
in some places (in particular, locking is needed for walking the
list pointed to it safely, but it is often missing).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/soundwire/slave.c |  115 ++++++++++++++++++++++++++--------------------
 1 file changed, 67 insertions(+), 48 deletions(-)

Comments

Pierre-Louis Bossart June 9, 2022, 3:22 p.m. UTC | #1 
Thanks Rafael. This looks mostly good but I have a doubt on the error
handling, see below.

> +static int sdw_acpi_check_duplicate(struct acpi_device *adev, void *data)
> +{
> +	struct sdw_acpi_child_walk_data *cwd = data;
> +	struct sdw_bus *bus = cwd->bus;
> +	struct sdw_slave_id id;
> +
> +	if (adev == cwd->adev)
> +		return 0;
> +
> +	if (!find_slave(bus, adev, &id))
> +		return 0;
> +
> +	if (cwd->id.sdw_version != id.sdw_version || cwd->id.mfg_id != id.mfg_id ||
> +	    cwd->id.part_id != id.part_id || cwd->id.class_id != id.class_id)
> +		return 0;
> +
> +	if (cwd->id.unique_id != id.unique_id) {
> +		dev_dbg(bus->dev,
> +			"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> +			cwd->id.unique_id, id.unique_id, cwd->id.mfg_id,
> +			cwd->id.part_id);
> +		cwd->ignore_unique_id = false;
> +		return 0;
> +	}
> +
> +	dev_err(bus->dev,
> +		"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> +		cwd->id.unique_id, id.unique_id, cwd->id.mfg_id, cwd->id.part_id);
> +	return -ENODEV;

if this error happens, I would guess it's reported ....

> +}
> +
> +static int sdw_acpi_find_one(struct acpi_device *adev, void *data)
> +{
> +	struct sdw_bus *bus = data;
> +	struct sdw_acpi_child_walk_data cwd = {
> +		.bus = bus,
> +		.adev = adev,
> +		.ignore_unique_id = true,
> +	};
> +	int ret;
> +
> +	if (!find_slave(bus, adev, &cwd.id))
> +		return 0;
> +
> +	/* Brute-force O(N^2) search for duplicates. */
> +	ret = acpi_dev_for_each_child(ACPI_COMPANION(bus->dev),
> +				      sdw_acpi_check_duplicate, &cwd);
> +	if (ret)
> +		return ret;

... here, but I don't see this being propagated further...

> +
> +	if (cwd.ignore_unique_id)
> +		cwd.id.unique_id = SDW_IGNORED_UNIQUE_ID;
> +
> +	/* Ignore errors and continue. */
> +	sdw_slave_add(bus, &cwd.id, acpi_fwnode_handle(adev));
> +	return 0;
> +}
> +
>  /*
>   * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
>   * @bus: SDW bus instance
> @@ -135,8 +200,7 @@ static bool find_slave(struct sdw_bus *b
>   */
>  int sdw_acpi_find_slaves(struct sdw_bus *bus)
>  {
> -	struct acpi_device *adev, *parent;
> -	struct acpi_device *adev2, *parent2;
> +	struct acpi_device *parent;
>  
>  	parent = ACPI_COMPANION(bus->dev);
>  	if (!parent) {
> @@ -144,52 +208,7 @@ int sdw_acpi_find_slaves(struct sdw_bus
>  		return -ENODEV;
>  	}
>  
> -	list_for_each_entry(adev, &parent->children, node) {
> -		struct sdw_slave_id id;
> -		struct sdw_slave_id id2;
> -		bool ignore_unique_id = true;
> -
> -		if (!find_slave(bus, adev, &id))
> -			continue;
> -
> -		/* brute-force O(N^2) search for duplicates */
> -		parent2 = parent;
> -		list_for_each_entry(adev2, &parent2->children, node) {
> -
> -			if (adev == adev2)
> -				continue;
> -
> -			if (!find_slave(bus, adev2, &id2))
> -				continue;
> -
> -			if (id.sdw_version != id2.sdw_version ||
> -			    id.mfg_id != id2.mfg_id ||
> -			    id.part_id != id2.part_id ||
> -			    id.class_id != id2.class_id)
> -				continue;
> -
> -			if (id.unique_id != id2.unique_id) {
> -				dev_dbg(bus->dev,
> -					"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> -					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> -				ignore_unique_id = false;
> -			} else {
> -				dev_err(bus->dev,
> -					"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> -					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> -				return -ENODEV;
> -			}
> -		}
> -
> -		if (ignore_unique_id)
> -			id.unique_id = SDW_IGNORED_UNIQUE_ID;
> -
> -		/*
> -		 * don't error check for sdw_slave_add as we want to continue
> -		 * adding Slaves
> -		 */
> -		sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
> -	}
> +	acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);

... here?

It looks like a change in the error handling flow where
sdw_acpi_find_slaves() is now returning 0 (success) always?

Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with

return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);

>  
>  	return 0;
>  }
> 
> 
>
Rafael J. Wysocki June 9, 2022, 4:13 p.m. UTC | #2 
On Thu, Jun 9, 2022 at 5:23 PM Pierre-Louis Bossart
<pierre-louis.bossart@linux.intel.com> wrote:
>
> Thanks Rafael. This looks mostly good but I have a doubt on the error
> handling, see below.
>
> > +static int sdw_acpi_check_duplicate(struct acpi_device *adev, void *data)
> > +{
> > +     struct sdw_acpi_child_walk_data *cwd = data;
> > +     struct sdw_bus *bus = cwd->bus;
> > +     struct sdw_slave_id id;
> > +
> > +     if (adev == cwd->adev)
> > +             return 0;
> > +
> > +     if (!find_slave(bus, adev, &id))
> > +             return 0;
> > +
> > +     if (cwd->id.sdw_version != id.sdw_version || cwd->id.mfg_id != id.mfg_id ||
> > +         cwd->id.part_id != id.part_id || cwd->id.class_id != id.class_id)
> > +             return 0;
> > +
> > +     if (cwd->id.unique_id != id.unique_id) {
> > +             dev_dbg(bus->dev,
> > +                     "Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > +                     cwd->id.unique_id, id.unique_id, cwd->id.mfg_id,
> > +                     cwd->id.part_id);
> > +             cwd->ignore_unique_id = false;
> > +             return 0;
> > +     }
> > +
> > +     dev_err(bus->dev,
> > +             "Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > +             cwd->id.unique_id, id.unique_id, cwd->id.mfg_id, cwd->id.part_id);
> > +     return -ENODEV;
>
> if this error happens, I would guess it's reported ....
>
> > +}
> > +
> > +static int sdw_acpi_find_one(struct acpi_device *adev, void *data)
> > +{
> > +     struct sdw_bus *bus = data;
> > +     struct sdw_acpi_child_walk_data cwd = {
> > +             .bus = bus,
> > +             .adev = adev,
> > +             .ignore_unique_id = true,
> > +     };
> > +     int ret;
> > +
> > +     if (!find_slave(bus, adev, &cwd.id))
> > +             return 0;
> > +
> > +     /* Brute-force O(N^2) search for duplicates. */
> > +     ret = acpi_dev_for_each_child(ACPI_COMPANION(bus->dev),
> > +                                   sdw_acpi_check_duplicate, &cwd);
> > +     if (ret)
> > +             return ret;
>
> ... here, but I don't see this being propagated further...
>
> > +
> > +     if (cwd.ignore_unique_id)
> > +             cwd.id.unique_id = SDW_IGNORED_UNIQUE_ID;
> > +
> > +     /* Ignore errors and continue. */
> > +     sdw_slave_add(bus, &cwd.id, acpi_fwnode_handle(adev));
> > +     return 0;
> > +}
> > +
> >  /*
> >   * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
> >   * @bus: SDW bus instance
> > @@ -135,8 +200,7 @@ static bool find_slave(struct sdw_bus *b
> >   */
> >  int sdw_acpi_find_slaves(struct sdw_bus *bus)
> >  {
> > -     struct acpi_device *adev, *parent;
> > -     struct acpi_device *adev2, *parent2;
> > +     struct acpi_device *parent;
> >
> >       parent = ACPI_COMPANION(bus->dev);
> >       if (!parent) {
> > @@ -144,52 +208,7 @@ int sdw_acpi_find_slaves(struct sdw_bus
> >               return -ENODEV;
> >       }
> >
> > -     list_for_each_entry(adev, &parent->children, node) {
> > -             struct sdw_slave_id id;
> > -             struct sdw_slave_id id2;
> > -             bool ignore_unique_id = true;
> > -
> > -             if (!find_slave(bus, adev, &id))
> > -                     continue;
> > -
> > -             /* brute-force O(N^2) search for duplicates */
> > -             parent2 = parent;
> > -             list_for_each_entry(adev2, &parent2->children, node) {
> > -
> > -                     if (adev == adev2)
> > -                             continue;
> > -
> > -                     if (!find_slave(bus, adev2, &id2))
> > -                             continue;
> > -
> > -                     if (id.sdw_version != id2.sdw_version ||
> > -                         id.mfg_id != id2.mfg_id ||
> > -                         id.part_id != id2.part_id ||
> > -                         id.class_id != id2.class_id)
> > -                             continue;
> > -
> > -                     if (id.unique_id != id2.unique_id) {
> > -                             dev_dbg(bus->dev,
> > -                                     "Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > -                                     id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> > -                             ignore_unique_id = false;
> > -                     } else {
> > -                             dev_err(bus->dev,
> > -                                     "Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
> > -                                     id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
> > -                             return -ENODEV;
> > -                     }
> > -             }
> > -
> > -             if (ignore_unique_id)
> > -                     id.unique_id = SDW_IGNORED_UNIQUE_ID;
> > -
> > -             /*
> > -              * don't error check for sdw_slave_add as we want to continue
> > -              * adding Slaves
> > -              */
> > -             sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
> > -     }
> > +     acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
>
> ... here?
>
> It looks like a change in the error handling flow where
> sdw_acpi_find_slaves() is now returning 0 (success) always?
>
> Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with
>
> return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);

Sure, I'll do that.  Thanks!
Pierre-Louis Bossart June 9, 2022, 4:21 p.m. UTC | #3 
>> Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with
>>
>> return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
> 
> Sure, I'll do that.  Thanks!

I also added this EXPORT_SYMBOL to work-around link errors, not sure if
this is in your tree already?

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c

index 86fa61a21826c..ade6259c19af6 100644

--- a/drivers/acpi/bus.c

+++ b/drivers/acpi/bus.c

@@ -1113,6 +1113,7 @@ int acpi_dev_for_each_child(struct acpi_device *adev,



        return device_for_each_child(&adev->dev, &adwc,
acpi_dev_for_one_check);

 }

+EXPORT_SYMBOL_GPL(acpi_dev_for_each_child);
Rafael J. Wysocki June 9, 2022, 5:35 p.m. UTC | #4 
On Thu, Jun 9, 2022 at 6:21 PM Pierre-Louis Bossart
<pierre-louis.bossart@linux.intel.com> wrote:
>
>
> >> Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with
> >>
> >> return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
> >
> > Sure, I'll do that.  Thanks!
>
> I also added this EXPORT_SYMBOL to work-around link errors, not sure if
> this is in your tree already?

One of the previous patches in the series is adding the export.

> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>
> index 86fa61a21826c..ade6259c19af6 100644
>
> --- a/drivers/acpi/bus.c
>
> +++ b/drivers/acpi/bus.c
>
> @@ -1113,6 +1113,7 @@ int acpi_dev_for_each_child(struct acpi_device *adev,
>
>
>
>         return device_for_each_child(&adev->dev, &adwc,
> acpi_dev_for_one_check);
>
>  }
>
> +EXPORT_SYMBOL_GPL(acpi_dev_for_each_child);
>
>
Pierre-Louis Bossart June 9, 2022, 7:08 p.m. UTC | #5 
On 6/9/22 12:35, Rafael J. Wysocki wrote:
> On Thu, Jun 9, 2022 at 6:21 PM Pierre-Louis Bossart
> <pierre-louis.bossart@linux.intel.com> wrote:
>>
>>
>>>> Shouldn't the return of sdw_acpi_find_one() be trapped, e.g. with
>>>>
>>>> return acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
>>>
>>> Sure, I'll do that.  Thanks!
>>
>> I also added this EXPORT_SYMBOL to work-around link errors, not sure if
>> this is in your tree already?
> 
> One of the previous patches in the series is adding the export.

ok. I ran a bunch of tests with those two changes, so feel free to take
my tags:

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Tested-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
diff mbox series

Patch

Index: linux-pm/drivers/soundwire/slave.c
===================================================================
--- linux-pm.orig/drivers/soundwire/slave.c
+++ linux-pm/drivers/soundwire/slave.c
@@ -127,6 +127,71 @@  static bool find_slave(struct sdw_bus *b
 	return true;
 }
 
+struct sdw_acpi_child_walk_data {
+	struct sdw_bus *bus;
+	struct acpi_device *adev;
+	struct sdw_slave_id id;
+	bool ignore_unique_id;
+};
+
+static int sdw_acpi_check_duplicate(struct acpi_device *adev, void *data)
+{
+	struct sdw_acpi_child_walk_data *cwd = data;
+	struct sdw_bus *bus = cwd->bus;
+	struct sdw_slave_id id;
+
+	if (adev == cwd->adev)
+		return 0;
+
+	if (!find_slave(bus, adev, &id))
+		return 0;
+
+	if (cwd->id.sdw_version != id.sdw_version || cwd->id.mfg_id != id.mfg_id ||
+	    cwd->id.part_id != id.part_id || cwd->id.class_id != id.class_id)
+		return 0;
+
+	if (cwd->id.unique_id != id.unique_id) {
+		dev_dbg(bus->dev,
+			"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
+			cwd->id.unique_id, id.unique_id, cwd->id.mfg_id,
+			cwd->id.part_id);
+		cwd->ignore_unique_id = false;
+		return 0;
+	}
+
+	dev_err(bus->dev,
+		"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
+		cwd->id.unique_id, id.unique_id, cwd->id.mfg_id, cwd->id.part_id);
+	return -ENODEV;
+}
+
+static int sdw_acpi_find_one(struct acpi_device *adev, void *data)
+{
+	struct sdw_bus *bus = data;
+	struct sdw_acpi_child_walk_data cwd = {
+		.bus = bus,
+		.adev = adev,
+		.ignore_unique_id = true,
+	};
+	int ret;
+
+	if (!find_slave(bus, adev, &cwd.id))
+		return 0;
+
+	/* Brute-force O(N^2) search for duplicates. */
+	ret = acpi_dev_for_each_child(ACPI_COMPANION(bus->dev),
+				      sdw_acpi_check_duplicate, &cwd);
+	if (ret)
+		return ret;
+
+	if (cwd.ignore_unique_id)
+		cwd.id.unique_id = SDW_IGNORED_UNIQUE_ID;
+
+	/* Ignore errors and continue. */
+	sdw_slave_add(bus, &cwd.id, acpi_fwnode_handle(adev));
+	return 0;
+}
+
 /*
  * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
  * @bus: SDW bus instance
@@ -135,8 +200,7 @@  static bool find_slave(struct sdw_bus *b
  */
 int sdw_acpi_find_slaves(struct sdw_bus *bus)
 {
-	struct acpi_device *adev, *parent;
-	struct acpi_device *adev2, *parent2;
+	struct acpi_device *parent;
 
 	parent = ACPI_COMPANION(bus->dev);
 	if (!parent) {
@@ -144,52 +208,7 @@  int sdw_acpi_find_slaves(struct sdw_bus
 		return -ENODEV;
 	}
 
-	list_for_each_entry(adev, &parent->children, node) {
-		struct sdw_slave_id id;
-		struct sdw_slave_id id2;
-		bool ignore_unique_id = true;
-
-		if (!find_slave(bus, adev, &id))
-			continue;
-
-		/* brute-force O(N^2) search for duplicates */
-		parent2 = parent;
-		list_for_each_entry(adev2, &parent2->children, node) {
-
-			if (adev == adev2)
-				continue;
-
-			if (!find_slave(bus, adev2, &id2))
-				continue;
-
-			if (id.sdw_version != id2.sdw_version ||
-			    id.mfg_id != id2.mfg_id ||
-			    id.part_id != id2.part_id ||
-			    id.class_id != id2.class_id)
-				continue;
-
-			if (id.unique_id != id2.unique_id) {
-				dev_dbg(bus->dev,
-					"Valid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
-					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
-				ignore_unique_id = false;
-			} else {
-				dev_err(bus->dev,
-					"Invalid unique IDs 0x%x 0x%x for Slave mfg_id 0x%04x, part_id 0x%04x\n",
-					id.unique_id, id2.unique_id, id.mfg_id, id.part_id);
-				return -ENODEV;
-			}
-		}
-
-		if (ignore_unique_id)
-			id.unique_id = SDW_IGNORED_UNIQUE_ID;
-
-		/*
-		 * don't error check for sdw_slave_add as we want to continue
-		 * adding Slaves
-		 */
-		sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
-	}
+	acpi_dev_for_each_child(parent, sdw_acpi_find_one, bus);
 
 	return 0;
 }