ACPI: scan: Rearrange dep_unmet initialization
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Message ID 2607573.mvXUDI8C0e@kreacher
State New, archived
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  • ACPI: scan: Rearrange dep_unmet initialization
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Commit Message

Rafael J. Wysocki May 10, 2021, 5:53 p.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The dep_unmet field in struct acpi_device is used to store the
number of unresolved _DEP dependencies (that is, operation region
dependencies for which there are no drivers present) for the ACPI
device object represented by it.

That field is initialized to 1 for all ACPI device objects in
acpi_add_single_object(), via acpi_init_device_object(), so as to
avoid evaluating _STA prematurely for battery device objects in
acpi_scan_init_status(), and it is "fixed up" in acpi_bus_check_add()
after the acpi_add_single_object() called by it has returned.

This is not particularly straightforward and causes dep_unmet to
remain 1 for device objects without dependencies created by invoking
acpi_add_single_object() directly, outside acpi_bus_check_add().

For this reason, rearrange acpi_add_single_object() to initialize
dep_unmet completely before calling acpi_scan_init_status(), which
requires passing one extra bool argument to it, and update all of
its callers accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/scan.c |   62 +++++++++++++++++++++++++---------------------------
 1 file changed, 30 insertions(+), 32 deletions(-)

Comments

Hans de Goede May 11, 2021, 11:24 a.m. UTC | #1
Hi Rafael,

On 5/10/21 7:53 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> The dep_unmet field in struct acpi_device is used to store the
> number of unresolved _DEP dependencies (that is, operation region
> dependencies for which there are no drivers present) for the ACPI
> device object represented by it.
> 
> That field is initialized to 1 for all ACPI device objects in
> acpi_add_single_object(), via acpi_init_device_object(), so as to
> avoid evaluating _STA prematurely for battery device objects in
> acpi_scan_init_status(), and it is "fixed up" in acpi_bus_check_add()
> after the acpi_add_single_object() called by it has returned.
> 
> This is not particularly straightforward and causes dep_unmet to
> remain 1 for device objects without dependencies created by invoking
> acpi_add_single_object() directly, outside acpi_bus_check_add().
> 
> For this reason, rearrange acpi_add_single_object() to initialize
> dep_unmet completely before calling acpi_scan_init_status(), which
> requires passing one extra bool argument to it, and update all of
> its callers accordingly.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Thanks, one small nitpick below.

> ---
>  drivers/acpi/scan.c |   62 +++++++++++++++++++++++++---------------------------
>  1 file changed, 30 insertions(+), 32 deletions(-)
> 
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -1670,8 +1670,22 @@ void acpi_init_device_object(struct acpi
>  	device_initialize(&device->dev);
>  	dev_set_uevent_suppress(&device->dev, true);
>  	acpi_init_coherency(device);
> -	/* Assume there are unmet deps to start with. */
> -	device->dep_unmet = 1;
> +}
> +
> +static void acpi_scan_dep_init(struct acpi_device *adev)
> +{
> +	struct acpi_dep_data *dep;
> +
> +	adev->dep_unmet = 0;

Now that we don't set dep_unmet to 1 in acpi_init_device_object()
anymore this line is no longer necessary.

dep_unmet is set to 0 by the kzalloc of the adev and we are already
relying on that in the case where the dep_init parameter to
acpi_add_single_object() is false.

But if you want to keep this that is fine too, either way
this patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans








> +
> +	mutex_lock(&acpi_dep_list_lock);
> +
> +	list_for_each_entry(dep, &acpi_dep_list, node) {
> +		if (dep->consumer == adev->handle)
> +			adev->dep_unmet++;
> +	}
> +
> +	mutex_unlock(&acpi_dep_list_lock);
>  }
>  
>  void acpi_device_add_finalize(struct acpi_device *device)
> @@ -1687,7 +1701,7 @@ static void acpi_scan_init_status(struct
>  }
>  
>  static int acpi_add_single_object(struct acpi_device **child,
> -				  acpi_handle handle, int type)
> +				  acpi_handle handle, int type, bool dep_init)
>  {
>  	struct acpi_device *device;
>  	int result;
> @@ -1702,8 +1716,12 @@ static int acpi_add_single_object(struct
>  	 * acpi_bus_get_status() and use its quirk handling.  Note that
>  	 * this must be done before the get power-/wakeup_dev-flags calls.
>  	 */
> -	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR)
> +	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
> +		if (dep_init)
> +			acpi_scan_dep_init(device);
> +
>  		acpi_scan_init_status(device);
> +	}
>  
>  	acpi_bus_get_power_flags(device);
>  	acpi_bus_get_wakeup_device_flags(device);
> @@ -1885,22 +1903,6 @@ static u32 acpi_scan_check_dep(acpi_hand
>  	return count;
>  }
>  
> -static void acpi_scan_dep_init(struct acpi_device *adev)
> -{
> -	struct acpi_dep_data *dep;
> -
> -	adev->dep_unmet = 0;
> -
> -	mutex_lock(&acpi_dep_list_lock);
> -
> -	list_for_each_entry(dep, &acpi_dep_list, node) {
> -		if (dep->consumer == adev->handle)
> -			adev->dep_unmet++;
> -	}
> -
> -	mutex_unlock(&acpi_dep_list_lock);
> -}
> -
>  static bool acpi_bus_scan_second_pass;
>  
>  static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
> @@ -1948,19 +1950,15 @@ static acpi_status acpi_bus_check_add(ac
>  		return AE_OK;
>  	}
>  
> -	acpi_add_single_object(&device, handle, type);
> -	if (!device)
> -		return AE_CTRL_DEPTH;
> -
> -	acpi_scan_init_hotplug(device);
>  	/*
>  	 * If check_dep is true at this point, the device has no dependencies,
>  	 * or the creation of the device object would have been postponed above.
>  	 */
> -	if (check_dep)
> -		device->dep_unmet = 0;
> -	else
> -		acpi_scan_dep_init(device);
> +	acpi_add_single_object(&device, handle, type, !check_dep);
> +	if (!device)
> +		return AE_CTRL_DEPTH;
> +
> +	acpi_scan_init_hotplug(device);
>  
>  out:
>  	if (!*adev_p)
> @@ -2222,7 +2220,7 @@ int acpi_bus_register_early_device(int t
>  	struct acpi_device *device = NULL;
>  	int result;
>  
> -	result = acpi_add_single_object(&device, NULL, type);
> +	result = acpi_add_single_object(&device, NULL, type, false);
>  	if (result)
>  		return result;
>  
> @@ -2242,7 +2240,7 @@ static int acpi_bus_scan_fixed(void)
>  		struct acpi_device *device = NULL;
>  
>  		result = acpi_add_single_object(&device, NULL,
> -						ACPI_BUS_TYPE_POWER_BUTTON);
> +						ACPI_BUS_TYPE_POWER_BUTTON, false);
>  		if (result)
>  			return result;
>  
> @@ -2258,7 +2256,7 @@ static int acpi_bus_scan_fixed(void)
>  		struct acpi_device *device = NULL;
>  
>  		result = acpi_add_single_object(&device, NULL,
> -						ACPI_BUS_TYPE_SLEEP_BUTTON);
> +						ACPI_BUS_TYPE_SLEEP_BUTTON, false);
>  		if (result)
>  			return result;
>  
> 
> 
>
Rafael J. Wysocki May 11, 2021, 11:42 a.m. UTC | #2
On Tue, May 11, 2021 at 1:24 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Rafael,
>
> On 5/10/21 7:53 PM, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > The dep_unmet field in struct acpi_device is used to store the
> > number of unresolved _DEP dependencies (that is, operation region
> > dependencies for which there are no drivers present) for the ACPI
> > device object represented by it.
> >
> > That field is initialized to 1 for all ACPI device objects in
> > acpi_add_single_object(), via acpi_init_device_object(), so as to
> > avoid evaluating _STA prematurely for battery device objects in
> > acpi_scan_init_status(), and it is "fixed up" in acpi_bus_check_add()
> > after the acpi_add_single_object() called by it has returned.
> >
> > This is not particularly straightforward and causes dep_unmet to
> > remain 1 for device objects without dependencies created by invoking
> > acpi_add_single_object() directly, outside acpi_bus_check_add().
> >
> > For this reason, rearrange acpi_add_single_object() to initialize
> > dep_unmet completely before calling acpi_scan_init_status(), which
> > requires passing one extra bool argument to it, and update all of
> > its callers accordingly.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Thanks, one small nitpick below.
>
> > ---
> >  drivers/acpi/scan.c |   62 +++++++++++++++++++++++++---------------------------
> >  1 file changed, 30 insertions(+), 32 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/scan.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/scan.c
> > +++ linux-pm/drivers/acpi/scan.c
> > @@ -1670,8 +1670,22 @@ void acpi_init_device_object(struct acpi
> >       device_initialize(&device->dev);
> >       dev_set_uevent_suppress(&device->dev, true);
> >       acpi_init_coherency(device);
> > -     /* Assume there are unmet deps to start with. */
> > -     device->dep_unmet = 1;
> > +}
> > +
> > +static void acpi_scan_dep_init(struct acpi_device *adev)
> > +{
> > +     struct acpi_dep_data *dep;
> > +
> > +     adev->dep_unmet = 0;
>
> Now that we don't set dep_unmet to 1 in acpi_init_device_object()
> anymore this line is no longer necessary.

Right.

I'll drop it before applying the patch.

> dep_unmet is set to 0 by the kzalloc of the adev and we are already
> relying on that in the case where the dep_init parameter to
> acpi_add_single_object() is false.
>
> But if you want to keep this that is fine too, either way
> this patch looks good to me:
>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Thank you!

Patch
diff mbox series

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1670,8 +1670,22 @@  void acpi_init_device_object(struct acpi
 	device_initialize(&device->dev);
 	dev_set_uevent_suppress(&device->dev, true);
 	acpi_init_coherency(device);
-	/* Assume there are unmet deps to start with. */
-	device->dep_unmet = 1;
+}
+
+static void acpi_scan_dep_init(struct acpi_device *adev)
+{
+	struct acpi_dep_data *dep;
+
+	adev->dep_unmet = 0;
+
+	mutex_lock(&acpi_dep_list_lock);
+
+	list_for_each_entry(dep, &acpi_dep_list, node) {
+		if (dep->consumer == adev->handle)
+			adev->dep_unmet++;
+	}
+
+	mutex_unlock(&acpi_dep_list_lock);
 }
 
 void acpi_device_add_finalize(struct acpi_device *device)
@@ -1687,7 +1701,7 @@  static void acpi_scan_init_status(struct
 }
 
 static int acpi_add_single_object(struct acpi_device **child,
-				  acpi_handle handle, int type)
+				  acpi_handle handle, int type, bool dep_init)
 {
 	struct acpi_device *device;
 	int result;
@@ -1702,8 +1716,12 @@  static int acpi_add_single_object(struct
 	 * acpi_bus_get_status() and use its quirk handling.  Note that
 	 * this must be done before the get power-/wakeup_dev-flags calls.
 	 */
-	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR)
+	if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
+		if (dep_init)
+			acpi_scan_dep_init(device);
+
 		acpi_scan_init_status(device);
+	}
 
 	acpi_bus_get_power_flags(device);
 	acpi_bus_get_wakeup_device_flags(device);
@@ -1885,22 +1903,6 @@  static u32 acpi_scan_check_dep(acpi_hand
 	return count;
 }
 
-static void acpi_scan_dep_init(struct acpi_device *adev)
-{
-	struct acpi_dep_data *dep;
-
-	adev->dep_unmet = 0;
-
-	mutex_lock(&acpi_dep_list_lock);
-
-	list_for_each_entry(dep, &acpi_dep_list, node) {
-		if (dep->consumer == adev->handle)
-			adev->dep_unmet++;
-	}
-
-	mutex_unlock(&acpi_dep_list_lock);
-}
-
 static bool acpi_bus_scan_second_pass;
 
 static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep,
@@ -1948,19 +1950,15 @@  static acpi_status acpi_bus_check_add(ac
 		return AE_OK;
 	}
 
-	acpi_add_single_object(&device, handle, type);
-	if (!device)
-		return AE_CTRL_DEPTH;
-
-	acpi_scan_init_hotplug(device);
 	/*
 	 * If check_dep is true at this point, the device has no dependencies,
 	 * or the creation of the device object would have been postponed above.
 	 */
-	if (check_dep)
-		device->dep_unmet = 0;
-	else
-		acpi_scan_dep_init(device);
+	acpi_add_single_object(&device, handle, type, !check_dep);
+	if (!device)
+		return AE_CTRL_DEPTH;
+
+	acpi_scan_init_hotplug(device);
 
 out:
 	if (!*adev_p)
@@ -2222,7 +2220,7 @@  int acpi_bus_register_early_device(int t
 	struct acpi_device *device = NULL;
 	int result;
 
-	result = acpi_add_single_object(&device, NULL, type);
+	result = acpi_add_single_object(&device, NULL, type, false);
 	if (result)
 		return result;
 
@@ -2242,7 +2240,7 @@  static int acpi_bus_scan_fixed(void)
 		struct acpi_device *device = NULL;
 
 		result = acpi_add_single_object(&device, NULL,
-						ACPI_BUS_TYPE_POWER_BUTTON);
+						ACPI_BUS_TYPE_POWER_BUTTON, false);
 		if (result)
 			return result;
 
@@ -2258,7 +2256,7 @@  static int acpi_bus_scan_fixed(void)
 		struct acpi_device *device = NULL;
 
 		result = acpi_add_single_object(&device, NULL,
-						ACPI_BUS_TYPE_SLEEP_BUTTON);
+						ACPI_BUS_TYPE_SLEEP_BUTTON, false);
 		if (result)
 			return result;