From: Lars Ellenberg <lars.ellenberg@linbit.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>,
drbd-dev@lists.linbit.com,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drbd: avoid clang warning about pointless switch statement
Date: Mon, 6 Feb 2017 14:43:23 +0100 [thread overview]
Message-ID: <20170206134323.GC16345@soda.linbit> (raw)
In-Reply-To: <20170201165532.2605534-1-arnd@arndb.de>
Ack.
Ok, not exactly "pintless", it's a valid compile time assert for uniq ids,
basically a BUILD_BUG_ON(duplicate-ids). But adding a default clause
there does not hurt.
Thanks,
Lars
On Wed, Feb 01, 2017 at 05:55:02PM +0100, Arnd Bergmann wrote:
> The drbd code causes warnings that we cannot easily disable when building with clang:
>
> In file included from drivers/block/drbd/drbd_debugfs.c:10:
> In file included from drivers/block/drbd/drbd_int.h:48:
> In file included from include/linux/drbd_genl_api.h:53:
> In file included from include/linux/genl_magic_struct.h:237:
> include/linux/drbd_genl.h:300:1: warning: no case matching constant switch condition '0'
>
> There is nothing wrong with the code, and adding 'default:' labels
> in the right place is enough to let clang shut up about the warning.
>
> Fixes: ec2c35ac1ea2 ("drbd: prepare the transition from connector to genetlink")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> include/linux/genl_magic_struct.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/genl_magic_struct.h b/include/linux/genl_magic_struct.h
> index 6270a56e5edc..c6fbafb834f1 100644
> --- a/include/linux/genl_magic_struct.h
> +++ b/include/linux/genl_magic_struct.h
> @@ -190,6 +190,7 @@ static inline void ct_assert_unique_operations(void)
> {
> switch (0) {
> #include GENL_MAGIC_INCLUDE_FILE
> + default:
> ;
> }
> }
> @@ -208,6 +209,7 @@ static inline void ct_assert_unique_top_level_attributes(void)
> {
> switch (0) {
> #include GENL_MAGIC_INCLUDE_FILE
> + default:
> ;
> }
> }
> @@ -218,6 +220,7 @@ static inline void ct_assert_unique_ ## s_name ## _attributes(void) \
> { \
> switch (0) { \
> s_fields \
> + default: \
> ; \
> } \
> }
> --
> 2.9.0
next prev parent reply other threads:[~2017-02-06 13:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-01 16:55 [PATCH] drbd: avoid clang warning about pointless switch statement Arnd Bergmann
2017-02-06 13:43 ` Lars Ellenberg [this message]
2018-09-12 10:01 Philipp Klocke
2018-09-12 10:24 ` Arnd Bergmann
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