From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> 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@xxxxxxxxx> --- drivers/mfd/mfd-core.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) Index: linux-pm/drivers/mfd/mfd-core.c =================================================================== --- linux-pm.orig/drivers/mfd/mfd-core.c +++ linux-pm/drivers/mfd/mfd-core.c @@ -60,12 +60,29 @@ int mfd_cell_disable(struct platform_dev EXPORT_SYMBOL(mfd_cell_disable); #if IS_ENABLED(CONFIG_ACPI) +struct match_ids_walk_data { + struct acpi_device_id *ids; + struct acpi_device *adev; +}; + +static int match_device_ids(struct acpi_device *adev, void *data) +{ + struct match_ids_walk_data *wd = data; + + if (!acpi_match_device_ids(adev, wd->ids)) { + wd->adev = adev; + return 1; + } + + return 0; +} + static void mfd_acpi_add_device(const struct mfd_cell *cell, struct platform_device *pdev) { const struct mfd_cell_acpi_match *match = cell->acpi_match; - struct acpi_device *parent, *child; struct acpi_device *adev = NULL; + struct acpi_device *parent; parent = ACPI_COMPANION(pdev->dev.parent); if (!parent) @@ -83,14 +100,14 @@ static void mfd_acpi_add_device(const st if (match) { if (match->pnpid) { struct acpi_device_id ids[2] = {}; + struct match_ids_walk_data wd = { + .adev = NULL, + .ids = ids, + }; strlcpy(ids[0].id, match->pnpid, sizeof(ids[0].id)); - list_for_each_entry(child, &parent->children, node) { - if (!acpi_match_device_ids(child, ids)) { - adev = child; - break; - } - } + acpi_dev_for_each_child(parent, match_device_ids, &wd); + adev = wd.adev; } else { adev = acpi_find_child_device(parent, match->adr, false); }