| Message ID | 20230815-void-drivers-net-mdio-mdio-xgene-v1-1-5304342e0659@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f3add6dec36d9d747929918ba1d7ce8866e1c054 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: mdio: fix -Wvoid-pointer-to-enum-cast warning | expand |
On Tue, Aug 15, 2023 at 08:35:59PM +0000, Justin Stitt wrote: > When building with clang 18 I see the following warning: > | drivers/net/mdio/mdio-xgene.c:338:13: warning: cast to smaller integer > | type 'enum xgene_mdio_id' from 'const void *' [-Wvoid-pointer-to-enum-cast] > | 338 | mdio_id = (enum xgene_mdio_id)of_id->data; > > This is due to the fact that `of_id->data` is a void* while `enum > xgene_mdio_id` has the size of an int. This leads to truncation and > possible data loss. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1910 > Reported-by: Nathan Chancellor <nathan@kernel.org> > Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
On Tue, Aug 15, 2023 at 10:41:39PM +0200, Andrew Lunn wrote: > On Tue, Aug 15, 2023 at 08:35:59PM +0000, Justin Stitt wrote: > > When building with clang 18 I see the following warning: > > | drivers/net/mdio/mdio-xgene.c:338:13: warning: cast to smaller integer > > | type 'enum xgene_mdio_id' from 'const void *' [-Wvoid-pointer-to-enum-cast] > > | 338 | mdio_id = (enum xgene_mdio_id)of_id->data; > > > > This is due to the fact that `of_id->data` is a void* while `enum > > xgene_mdio_id` has the size of an int. This leads to truncation and > > possible data loss. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/1910 > > Reported-by: Nathan Chancellor <nathan@kernel.org> > > Signed-off-by: Justin Stitt <justinstitt@google.com> > > Reviewed-by: Andrew Lunn <andrew@lunn.ch> I wonder whether it would be better to use device_get_match_data() here? The whole of_match_device()...acpi_match_device() dance could become: + mdio_id = (uintptr_t)device_get_match_data(&pdev->dev); if (!mdio_id) return -ENODEV; It's probably something for a follow-up patch though. Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Thanks!
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Tue, 15 Aug 2023 20:35:59 +0000 you wrote: > When building with clang 18 I see the following warning: > | drivers/net/mdio/mdio-xgene.c:338:13: warning: cast to smaller integer > | type 'enum xgene_mdio_id' from 'const void *' [-Wvoid-pointer-to-enum-cast] > | 338 | mdio_id = (enum xgene_mdio_id)of_id->data; > > This is due to the fact that `of_id->data` is a void* while `enum > xgene_mdio_id` has the size of an int. This leads to truncation and > possible data loss. > > [...] Here is the summary with links: - net: mdio: fix -Wvoid-pointer-to-enum-cast warning https://git.kernel.org/netdev/net-next/c/f3add6dec36d You are awesome, thank you!
diff --git a/drivers/net/mdio/mdio-xgene.c b/drivers/net/mdio/mdio-xgene.c index 7aafc221b5cf..7119eb11c00d 100644 --- a/drivers/net/mdio/mdio-xgene.c +++ b/drivers/net/mdio/mdio-xgene.c @@ -335,7 +335,7 @@ static int xgene_mdio_probe(struct platform_device *pdev) of_id = of_match_device(xgene_mdio_of_match, &pdev->dev); if (of_id) { - mdio_id = (enum xgene_mdio_id)of_id->data; + mdio_id = (uintptr_t)of_id->data; } else { #ifdef CONFIG_ACPI const struct acpi_device_id *acpi_id;
When building with clang 18 I see the following warning: | drivers/net/mdio/mdio-xgene.c:338:13: warning: cast to smaller integer | type 'enum xgene_mdio_id' from 'const void *' [-Wvoid-pointer-to-enum-cast] | 338 | mdio_id = (enum xgene_mdio_id)of_id->data; This is due to the fact that `of_id->data` is a void* while `enum xgene_mdio_id` has the size of an int. This leads to truncation and possible data loss. Link: https://github.com/ClangBuiltLinux/linux/issues/1910 Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: `xgene_mdio_id` has only two fields enumerated from 1 which means this is no data loss happening here. Either way, this patch helps the goal of eventually enabling this warning for more builds by reducing noise. --- drivers/net/mdio/mdio-xgene.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 2ccdd1b13c591d306f0401d98dedc4bdcd02b421 change-id: 20230815-void-drivers-net-mdio-mdio-xgene-e5b3b4a3343b Best regards, -- Justin Stitt <justinstitt@google.com>