linux-kernel - [PATCH v1] ACPI: processor: idle: Eliminate static variable flat_state

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Message-ID: <10715991.nUPlyArG6x@rafael.j.wysocki>
Date: Wed, 13 Aug 2025 12:38:58 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux ACPI <linux-acpi@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Linux PM <linux-pm@...r.kernel.org>,
 Sudeep Holla <sudeep.holla@....com>,
 Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject:
 [PATCH v1] ACPI: processor: idle: Eliminate static variable flat_state_cnt

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Instead of using static variable flat_state_cnt to pass data between
functions involved in the _LPI information processing, pass the current
number of "flattened" idle states to flatten_lpi_states() and make it
return the updated number of those states.  At the same time, use a
local variable called state_count to store the number of "flattened"
idle states found so far in acpi_processor_get_lpi_info().

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/processor_idle.c |   25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -998,11 +998,6 @@
 	return ret;
 }
 
-/*
- * flat_state_cnt - the number of composite LPI states after the process of flattening
- */
-static int flat_state_cnt;
-
 /**
  * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
  *
@@ -1045,9 +1040,10 @@
 	curr_level->composite_states[curr_level->composite_states_size++] = t;
 }
 
-static int flatten_lpi_states(struct acpi_processor *pr,
-			      struct acpi_lpi_states_array *curr_level,
-			      struct acpi_lpi_states_array *prev_level)
+static unsigned int flatten_lpi_states(struct acpi_processor *pr,
+				       unsigned int flat_state_cnt,
+				       struct acpi_lpi_states_array *curr_level,
+				       struct acpi_lpi_states_array *prev_level)
 {
 	int i, j, state_count = curr_level->size;
 	struct acpi_lpi_state *p, *t = curr_level->entries;
@@ -1087,7 +1083,7 @@
 	}
 
 	kfree(curr_level->entries);
-	return 0;
+	return flat_state_cnt;
 }
 
 int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
@@ -1102,6 +1098,7 @@
 	acpi_handle handle = pr->handle, pr_ahandle;
 	struct acpi_device *d = NULL;
 	struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
+	unsigned int state_count;
 
 	/* make sure our architecture has support */
 	ret = acpi_processor_ffh_lpi_probe(pr->id);
@@ -1114,14 +1111,13 @@
 	if (!acpi_has_method(handle, "_LPI"))
 		return -EINVAL;
 
-	flat_state_cnt = 0;
 	prev = &info[0];
 	curr = &info[1];
 	handle = pr->handle;
 	ret = acpi_processor_evaluate_lpi(handle, prev);
 	if (ret)
 		return ret;
-	flatten_lpi_states(pr, prev, NULL);
+	state_count = flatten_lpi_states(pr, 0, prev, NULL);
 
 	status = acpi_get_parent(handle, &pr_ahandle);
 	while (ACPI_SUCCESS(status)) {
@@ -1143,18 +1139,19 @@
 			break;
 
 		/* flatten all the LPI states in this level of hierarchy */
-		flatten_lpi_states(pr, curr, prev);
+		state_count = flatten_lpi_states(pr, state_count, curr, prev);
 
 		tmp = prev, prev = curr, curr = tmp;
 
 		status = acpi_get_parent(handle, &pr_ahandle);
 	}
 
-	pr->power.count = flat_state_cnt;
 	/* reset the index after flattening */
-	for (i = 0; i < pr->power.count; i++)
+	for (i = 0; i < state_count; i++)
 		pr->power.lpi_states[i].index = i;
 
+	pr->power.count = state_count;
+
 	/* Tell driver that _LPI is supported. */
 	pr->flags.has_lpi = 1;
 	pr->flags.power = 1;