linux-kernel - [PATCH v3 1/6] ACPI: AC: Remove unnecessary checks

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Date:   Wed, 11 Oct 2023 11:33:29 +0300
From:   Michal Wilczynski <michal.wilczynski@...el.com>
To:     linux-acpi@...r.kernel.org
Cc:     rafael@...nel.org, dan.j.williams@...el.com,
        vishal.l.verma@...el.com, lenb@...nel.org, dave.jiang@...el.com,
        ira.weiny@...el.com, rui.zhang@...el.com,
        linux-kernel@...r.kernel.org, nvdimm@...ts.linux.dev,
        Michal Wilczynski <michal.wilczynski@...el.com>
Subject: [PATCH v3 1/6] ACPI: AC: Remove unnecessary checks

Remove unnecessary checks for NULL for variables that can't be NULL at
the point they're checked for it. Defensive programming is discouraged
in the kernel.

Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
---
 drivers/acpi/ac.c | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/drivers/acpi/ac.c b/drivers/acpi/ac.c
index aac3e561790c..83d45c681121 100644
--- a/drivers/acpi/ac.c
+++ b/drivers/acpi/ac.c
@@ -131,9 +131,6 @@ static void acpi_ac_notify(acpi_handle handle, u32 event, void *data)
 	struct acpi_device *device = data;
 	struct acpi_ac *ac = acpi_driver_data(device);
 
-	if (!ac)
-		return;
-
 	switch (event) {
 	default:
 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
@@ -216,12 +213,8 @@ static const struct dmi_system_id ac_dmi_table[]  __initconst = {
 static int acpi_ac_add(struct acpi_device *device)
 {
 	struct power_supply_config psy_cfg = {};
-	int result = 0;
-	struct acpi_ac *ac = NULL;
-
-
-	if (!device)
-		return -EINVAL;
+	struct acpi_ac *ac;
+	int result;
 
 	ac = kzalloc(sizeof(struct acpi_ac), GFP_KERNEL);
 	if (!ac)
@@ -275,16 +268,9 @@ static int acpi_ac_add(struct acpi_device *device)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_ac_resume(struct device *dev)
 {
-	struct acpi_ac *ac;
+	struct acpi_ac *ac = acpi_driver_data(to_acpi_device(dev));
 	unsigned int old_state;
 
-	if (!dev)
-		return -EINVAL;
-
-	ac = acpi_driver_data(to_acpi_device(dev));
-	if (!ac)
-		return -EINVAL;
-
 	old_state = ac->state;
 	if (acpi_ac_get_state(ac))
 		return 0;
@@ -299,12 +285,7 @@ static int acpi_ac_resume(struct device *dev)
 
 static void acpi_ac_remove(struct acpi_device *device)
 {
-	struct acpi_ac *ac = NULL;
-
-	if (!device || !acpi_driver_data(device))
-		return;
-
-	ac = acpi_driver_data(device);
+	struct acpi_ac *ac = acpi_driver_data(device);
 
 	acpi_dev_remove_notify_handler(device, ACPI_ALL_NOTIFY,
 				       acpi_ac_notify);
-- 
2.41.0