netdev - [PATCH 2/3] s390/smsgiucv_app: Remove function pointer cast

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Message-Id: <20240417-s390-drivers-fix-cast-function-type-v1-2-fd048c9903b0@kernel.org>
Date: Wed, 17 Apr 2024 11:24:36 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: akpm@...ux-foundation.org, arnd@...db.de, hca@...ux.ibm.com, 
 gor@...ux.ibm.com, agordeev@...ux.ibm.com
Cc: borntraeger@...ux.ibm.com, svens@...ux.ibm.com, wintera@...ux.ibm.com, 
 twinkler@...ux.ibm.com, linux-s390@...r.kernel.org, netdev@...r.kernel.org, 
 llvm@...ts.linux.dev, patches@...ts.linux.dev, 
 Nathan Chancellor <nathan@...nel.org>
Subject: [PATCH 2/3] s390/smsgiucv_app: Remove function pointer cast

Clang warns (or errors with CONFIG_WERROR) after enabling
-Wcast-function-type-strict by default:

  drivers/s390/net/smsgiucv_app.c:176:26: error: cast from 'void (*)(const void *)' to 'void (*)(struct device *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
    176 |         smsg_app_dev->release = (void (*)(struct device *)) kfree;
        |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  1 error generated.

Add a standalone function to fix the warning properly, which addresses
the root of the warning that these casts are not safe for kCFI.

Signed-off-by: Nathan Chancellor <nathan@...nel.org>
---
 drivers/s390/net/smsgiucv_app.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c
index 0a263999f7ae..390aba4ef7ad 100644
--- a/drivers/s390/net/smsgiucv_app.c
+++ b/drivers/s390/net/smsgiucv_app.c
@@ -64,6 +64,11 @@ static void smsg_app_event_free(struct smsg_app_event *ev)
 	kfree(ev);
 }
 
+static void smsg_app_free_dev(struct device *dev)
+{
+	kfree(dev);
+}
+
 static struct smsg_app_event *smsg_app_event_alloc(const char *from,
 						   const char *msg)
 {
@@ -173,7 +178,7 @@ static int __init smsgiucv_app_init(void)
 	}
 	smsg_app_dev->bus = &iucv_bus;
 	smsg_app_dev->parent = iucv_root;
-	smsg_app_dev->release = (void (*)(struct device *)) kfree;
+	smsg_app_dev->release = smsg_app_free_dev;
 	smsg_app_dev->driver = smsgiucv_drv;
 	rc = device_register(smsg_app_dev);
 	if (rc) {

-- 
2.44.0