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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>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        john.garry@huawei.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH v2] hisi_lpc: Use acpi_dev_for_each_child()
Date:   Wed, 29 Jun 2022 15:47:21 +0200
Message-ID: <2657553.mvXUDI8C0e@kreacher>
In-Reply-To: <12026357.O9o76ZdvQC@kreacher>
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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>
Acked-by: John Garry <john.garry@huawei.com>
---

-> v2:
   * Drop unused local variable (John).
   * Add ACK from John.

---
 drivers/bus/hisi_lpc.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Index: linux-pm/drivers/bus/hisi_lpc.c
===================================================================
--- linux-pm.orig/drivers/bus/hisi_lpc.c
+++ linux-pm/drivers/bus/hisi_lpc.c
@@ -471,6 +471,12 @@ static int hisi_lpc_acpi_remove_subdev(s
 	return 0;
 }
 
+static int hisi_lpc_acpi_clear_enumerated(struct acpi_device *adev, void *not_used)
+{
+	acpi_device_clear_enumerated(adev);
+	return 0;
+}
+
 struct hisi_lpc_acpi_cell {
 	const char *hid;
 	const char *name;
@@ -480,13 +486,9 @@ struct hisi_lpc_acpi_cell {
 
 static void hisi_lpc_acpi_remove(struct device *hostdev)
 {
-	struct acpi_device *adev = ACPI_COMPANION(hostdev);
-	struct acpi_device *child;
-
 	device_for_each_child(hostdev, NULL, hisi_lpc_acpi_remove_subdev);
-
-	list_for_each_entry(child, &adev->children, node)
-		acpi_device_clear_enumerated(child);
+	acpi_dev_for_each_child(ACPI_COMPANION(hostdev),
+				hisi_lpc_acpi_clear_enumerated, NULL);
 }
 
 /*