From: Stephen Hemminger <stephen@networkplumber.org>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Potnuri Bharat Teja <bharat@chelsio.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Jiri Pirko <jiri@resnulli.us>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2][next] UAPI: net/sched: Avoid -Wflex-array-member-not-at-end warning
Date: Fri, 9 Aug 2024 09:42:03 -0700 [thread overview]
Message-ID: <20240809094203.378b5224@hermes.local> (raw)
In-Reply-To: <ZrY1d01+JrX/SwqB@cute>
On Fri, 9 Aug 2024 09:27:51 -0600
"Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:
> -Wflex-array-member-not-at-end has been introduced in GCC-14, and we
> are getting ready to enable it, globally.
>
> So, in order to avoid ending up with a flexible-array member in the
> middle of multiple other structs, we use the `__struct_group()`
> helper to create a new tagged `struct tc_u32_sel_hdr`. This structure
> groups together all the members of the flexible `struct tc_u32_sel`
> except the flexible array.
>
> As a result, the array is effectively separated from the rest of the
> members without modifying the memory layout of the flexible structure.
> We then change the type of the middle struct member currently causing
> trouble from `struct tc_u32_sel` to `struct tc_u32_sel_hdr`.
>
> This approach avoids having to implement `struct tc_u32_sel_hdr`
> as a completely separate structure, thus preventing having to maintain
> two independent but basically identical structures, closing the door
> to potential bugs in the future.
>
> So, with these changes, fix the following warning:
> drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32_parse.h:245:27: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Tested this with iproute2-next and clang and no problem.
The patch might be better split into two parts?
next prev parent reply other threads:[~2024-08-09 16:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-09 15:27 [PATCH v2][next] UAPI: net/sched: Avoid -Wflex-array-member-not-at-end warning Gustavo A. R. Silva
2024-08-09 16:42 ` Stephen Hemminger [this message]
2024-08-13 0:55 ` Jakub Kicinski
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