linux-kernel - [PATCH v2] ipmi: make ipmi_destroy

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Message-ID: <20241225014532.20091-1-v.shevtsov@maxima.ru>
Date: Wed, 25 Dec 2024 01:45:30 +0000
From: Vitaliy Shevtsov <v.shevtsov@...ima.ru>
To: Corey Minyard <minyard@....org>
CC: Vitaliy Shevtsov <v.shevtsov@...ima.ru>,
	<openipmi-developer@...ts.sourceforge.net>, <linux-kernel@...r.kernel.org>,
	<lvc-project@...uxtesting.org>
Subject: [PATCH v2] ipmi: make ipmi_destroy_user() return void

Return value of ipmi_destroy_user() has no meaning, because it's always
zero and callers can do nothing with it. And in most cases it's not
checked. So make this function return void. This also will eliminate static
code analyzer warnings such as unreachable code/redundant comparison when
the return value is checked against non-zero value.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Vitaliy Shevtsov <v.shevtsov@...ima.ru>
---
v2: Add changes in drivers/char/ipmi/ipmi_poweroff.c missed by chance

 drivers/char/ipmi/ipmi_devintf.c    | 5 +----
 drivers/char/ipmi/ipmi_msghandler.c | 4 +---
 drivers/char/ipmi/ipmi_poweroff.c   | 6 +-----
 drivers/char/ipmi/ipmi_watchdog.c   | 5 +----
 include/linux/ipmi.h                | 2 +-
 5 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index 332082e02ea5..e6ba35b71f10 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -122,12 +122,9 @@ static int ipmi_open(struct inode *inode, struct file *file)
 static int ipmi_release(struct inode *inode, struct file *file)
 {
 	struct ipmi_file_private *priv = file->private_data;
-	int                      rv;
 	struct ipmi_recv_msg *msg, *next;
 
-	rv = ipmi_destroy_user(priv->user);
-	if (rv)
-		return rv;
+	ipmi_destroy_user(priv->user);
 
 	list_for_each_entry_safe(msg, next, &priv->recv_msgs, link)
 		ipmi_free_recv_msg(msg);
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index e12b531f5c2f..1e5313748f8b 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -1398,13 +1398,11 @@ static void _ipmi_destroy_user(struct ipmi_user *user)
 	module_put(owner);
 }
 
-int ipmi_destroy_user(struct ipmi_user *user)
+void ipmi_destroy_user(struct ipmi_user *user)
 {
 	_ipmi_destroy_user(user);
 
 	kref_put(&user->refcount, free_user);
-
-	return 0;
 }
 EXPORT_SYMBOL(ipmi_destroy_user);
 
diff --git a/drivers/char/ipmi/ipmi_poweroff.c b/drivers/char/ipmi/ipmi_poweroff.c
index 941d2dcc8c9d..05f17e3e6207 100644
--- a/drivers/char/ipmi/ipmi_poweroff.c
+++ b/drivers/char/ipmi/ipmi_poweroff.c
@@ -699,8 +699,6 @@ static int __init ipmi_poweroff_init(void)
 #ifdef MODULE
 static void __exit ipmi_poweroff_cleanup(void)
 {
-	int rv;
-
 #ifdef CONFIG_PROC_FS
 	unregister_sysctl_table(ipmi_table_header);
 #endif
@@ -708,9 +706,7 @@ static void __exit ipmi_poweroff_cleanup(void)
 	ipmi_smi_watcher_unregister(&smi_watcher);
 
 	if (ready) {
-		rv = ipmi_destroy_user(ipmi_user);
-		if (rv)
-			pr_err("could not cleanup the IPMI user: 0x%x\n", rv);
+		ipmi_destroy_user(ipmi_user);
 		pm_power_off = old_poweroff_func;
 	}
 }
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 335eea80054e..f1875b2bebbc 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -1064,7 +1064,6 @@ static void ipmi_register_watchdog(int ipmi_intf)
 
 static void ipmi_unregister_watchdog(int ipmi_intf)
 {
-	int rv;
 	struct ipmi_user *loc_user = watchdog_user;
 
 	if (!loc_user)
@@ -1089,9 +1088,7 @@ static void ipmi_unregister_watchdog(int ipmi_intf)
 	mutex_lock(&ipmi_watchdog_mutex);
 
 	/* Disconnect from IPMI. */
-	rv = ipmi_destroy_user(loc_user);
-	if (rv)
-		pr_warn("error unlinking from IPMI: %d\n",  rv);
+	ipmi_destroy_user(loc_user);
 
 	/* If it comes back, restart it properly. */
 	ipmi_start_timer_on_heartbeat = 1;
diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
index a1c9c0d48ebf..2f74dd90c271 100644
--- a/include/linux/ipmi.h
+++ b/include/linux/ipmi.h
@@ -126,7 +126,7 @@ int ipmi_create_user(unsigned int          if_num,
  * the users before you destroy the callback structures, it should be
  * safe, too.
  */
-int ipmi_destroy_user(struct ipmi_user *user);
+void ipmi_destroy_user(struct ipmi_user *user);
 
 /* Get the IPMI version of the BMC we are talking to. */
 int ipmi_get_version(struct ipmi_user *user,
-- 
2.47.1