diff mbox series

cxgb: avoid open-coded offsetof()

Message ID 20210927121611.940046-1-arnd@kernel.org (mailing list archive)
State Accepted
Commit ef5d6356e2ace045fd388c1b6effb2253642b5c4
Delegated to: Netdev Maintainers
Headers show
Series cxgb: avoid open-coded offsetof() | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Arnd Bergmann Sept. 27, 2021, 12:16 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

clang-14 does not like the custom offsetof() macro in vsc7326:

drivers/net/ethernet/chelsio/cxgb/vsc7326.c:597:3: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
                HW_STAT(RxUnicast, RxUnicastFramesOK),
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/chelsio/cxgb/vsc7326.c:594:56: note: expanded from macro 'HW_STAT'
        { reg, (&((struct cmac_statistics *)NULL)->stat_name) - (u64 *)NULL }

Rewrite this to use the version provided by the kernel.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/chelsio/cxgb/vsc7326.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

patchwork-bot+netdevbpf@kernel.org Sept. 27, 2021, 1:10 p.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 27 Sep 2021 14:16:04 +0200 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> clang-14 does not like the custom offsetof() macro in vsc7326:
> 
> drivers/net/ethernet/chelsio/cxgb/vsc7326.c:597:3: error: performing pointer subtraction with a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
>                 HW_STAT(RxUnicast, RxUnicastFramesOK),
>                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/ethernet/chelsio/cxgb/vsc7326.c:594:56: note: expanded from macro 'HW_STAT'
>         { reg, (&((struct cmac_statistics *)NULL)->stat_name) - (u64 *)NULL }
> 
> [...]

Here is the summary with links:
  - cxgb: avoid open-coded offsetof()
    https://git.kernel.org/netdev/net-next/c/ef5d6356e2ac

You are awesome, thank you!
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diff mbox series

Patch

diff --git a/drivers/net/ethernet/chelsio/cxgb/vsc7326.c b/drivers/net/ethernet/chelsio/cxgb/vsc7326.c
index 873c1c7b4ca0..a19284bdb80e 100644
--- a/drivers/net/ethernet/chelsio/cxgb/vsc7326.c
+++ b/drivers/net/ethernet/chelsio/cxgb/vsc7326.c
@@ -591,7 +591,7 @@  static void port_stats_update(struct cmac *mac)
 	} hw_stats[] = {
 
 #define HW_STAT(reg, stat_name) \
-	{ reg, (&((struct cmac_statistics *)NULL)->stat_name) - (u64 *)NULL }
+	{ reg, offsetof(struct cmac_statistics, stat_name) / sizeof(u64) }
 
 		/* Rx stats */
 		HW_STAT(RxUnicast, RxUnicastFramesOK),