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[3/3] s390/netiucv: Remove function pointer cast

Message ID 20240417-s390-drivers-fix-cast-function-type-v1-3-fd048c9903b0@kernel.org (mailing list archive)
State Not Applicable
Headers show
Series drivers/s390: Fix instances of -Wcast-function-type-strict | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Nathan Chancellor April 17, 2024, 6:24 p.m. UTC
Clang warns (or errors with CONFIG_WERROR) after enabling
-Wcast-function-type-strict by default:

  drivers/s390/net/netiucv.c:1716:18: error: cast from 'void (*)(const void *)' to 'void (*)(struct device *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
   1716 |                 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. The
comment is not really relevant after this change, so remove it.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/s390/net/netiucv.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

Comments

Arnd Bergmann April 17, 2024, 6:57 p.m. UTC | #1
On Wed, Apr 17, 2024, at 20:24, Nathan Chancellor wrote:
> Clang warns (or errors with CONFIG_WERROR) after enabling
> -Wcast-function-type-strict by default:
>
>   drivers/s390/net/netiucv.c:1716:18: error: cast from 'void (*)(const 
> void *)' to 'void (*)(struct device *)' converts to incompatible 
> function type [-Werror,-Wcast-function-type-strict]
>    1716 |                 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. The
> comment is not really relevant after this change, so remove it.
>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Thomas Huth April 18, 2024, 5:57 a.m. UTC | #2
On 17/04/2024 20.24, Nathan Chancellor wrote:
> Clang warns (or errors with CONFIG_WERROR) after enabling
> -Wcast-function-type-strict by default:
> 
>    drivers/s390/net/netiucv.c:1716:18: error: cast from 'void (*)(const void *)' to 'void (*)(struct device *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
>     1716 |                 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. The
> comment is not really relevant after this change, so remove it.
> 
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>   drivers/s390/net/netiucv.c | 14 ++++++--------
>   1 file changed, 6 insertions(+), 8 deletions(-)

Reviewed-by: Thomas Huth <thuth@redhat.com>
diff mbox series

Patch

diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index 8852b03f943b..11df20bfc9fa 100644
--- a/drivers/s390/net/netiucv.c
+++ b/drivers/s390/net/netiucv.c
@@ -1693,6 +1693,11 @@  static const struct attribute_group *netiucv_attr_groups[] = {
 	NULL,
 };
 
+static void netiucv_free_dev(struct device *dev)
+{
+	kfree(dev);
+}
+
 static int netiucv_register_device(struct net_device *ndev)
 {
 	struct netiucv_priv *priv = netdev_priv(ndev);
@@ -1706,14 +1711,7 @@  static int netiucv_register_device(struct net_device *ndev)
 		dev->bus = &iucv_bus;
 		dev->parent = iucv_root;
 		dev->groups = netiucv_attr_groups;
-		/*
-		 * The release function could be called after the
-		 * module has been unloaded. It's _only_ task is to
-		 * free the struct. Therefore, we specify kfree()
-		 * directly here. (Probably a little bit obfuscating
-		 * but legitime ...).
-		 */
-		dev->release = (void (*)(struct device *))kfree;
+		dev->release = netiucv_free_dev;
 		dev->driver = &netiucv_driver;
 	} else
 		return -ENOMEM;