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From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Linux ACPI <linux-acpi@vger.kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        linux-usb@vger.kernel.org
Subject: [PATCH v2 03/16] ACPI: glue: Introduce acpi_find_child_by_adr()
Date:   Mon, 13 Jun 2022 20:10:03 +0200
Message-ID: <13055097.uLZWGnKmhe@kreacher>
In-Reply-To: <2653857.mvXUDI8C0e@kreacher>
References: <1843211.tdWV9SEqCh@kreacher> <2653857.mvXUDI8C0e@kreacher>
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Rearrange the ACPI device lookup code used internally by
acpi_find_child_device() so it can avoid extra checks after finding
one object with a matching _ADR and use it for defining
acpi_find_child_by_adr() that will allow the callers to find a given
ACPI device's child matching a given bus address without doing any
other checks in check_one_child().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---

v1 -> v2:
   * Add R-by from Andy.

---
 drivers/acpi/glue.c     |   28 ++++++++++++++++++++++++----
 include/acpi/acpi_bus.h |    2 ++
 2 files changed, 26 insertions(+), 4 deletions(-)

Index: linux-pm/include/acpi/acpi_bus.h
===================================================================
--- linux-pm.orig/include/acpi/acpi_bus.h
+++ linux-pm/include/acpi/acpi_bus.h
@@ -622,6 +622,8 @@ static inline int acpi_dma_configure(str
 }
 struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
 					   u64 address, bool check_children);
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr);
 int acpi_is_root_bridge(acpi_handle);
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle);
 
Index: linux-pm/drivers/acpi/glue.c
===================================================================
--- linux-pm.orig/drivers/acpi/glue.c
+++ linux-pm/drivers/acpi/glue.c
@@ -119,6 +119,7 @@ struct find_child_walk_data {
 	struct acpi_device *adev;
 	u64 address;
 	int score;
+	bool check_sta;
 	bool check_children;
 };
 
@@ -131,9 +132,13 @@ static int check_one_child(struct acpi_d
 		return 0;
 
 	if (!wd->adev) {
-		/* This is the first matching object.  Save it and continue. */
+		/*
+		 * This is the first matching object, so save it.  If it is not
+		 * necessary to look for any other matching objects, stop the
+		 * search.
+		 */
 		wd->adev = adev;
-		return 0;
+		return !(wd->check_sta || wd->check_children);
 	}
 
 	/*
@@ -169,12 +174,14 @@ static int check_one_child(struct acpi_d
 	return 0;
 }
 
-struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
-					   u64 address, bool check_children)
+static struct acpi_device *acpi_find_child(struct acpi_device *parent,
+					   u64 address, bool check_children,
+					   bool check_sta)
 {
 	struct find_child_walk_data wd = {
 		.address = address,
 		.check_children = check_children,
+		.check_sta = check_sta,
 		.adev = NULL,
 		.score = 0,
 	};
@@ -184,8 +191,21 @@ struct acpi_device *acpi_find_child_devi
 
 	return wd.adev;
 }
+
+struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
+					   u64 address, bool check_children)
+{
+	return acpi_find_child(parent, address, check_children, true);
+}
 EXPORT_SYMBOL_GPL(acpi_find_child_device);
 
+struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
+					   acpi_bus_address adr)
+{
+	return acpi_find_child(adev, adr, false, false);
+}
+EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);
+
 static void acpi_physnode_link_name(char *buf, unsigned int node_id)
 {
 	if (node_id > 0)