Re: [PATCH] infiniband: shut up a maybe-uninitialized warning

From	Doug Ledford <dledford@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] infiniband: shut up a maybe-uninitialized warning
Date	2016-08-02 20:30 +0200
Message-ID	<s1MBZ-8c3-67@gated-at.bofh.it> (permalink)
References	<rRdFv-7cY-1@gated-at.bofh.it>
Organization	Red Hat, Inc.

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On Mon, 2016-07-04 at 17:06 +0200, Arnd Bergmann wrote:
> The powerpc64 default configuration leads to warnings for the
> infiniband
> core code:
> 
> infiniband/core/cma.c: In function 'cma_get_net_dev':
> infiniband/core/cma.c:1242:12: warning:
> 'src_addr_storage.sin_addr.s_addr' may be used uninitialized in this
> function [-Wmaybe-uninitialized]
> 
> The code looks correct to me, and I don't see the warnings on the
> other architectures, so this is a dumb change to add an unneeded
> initialization to the variables in order to shut up the warning.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Link: http://arm-soc.lixom.net/buildlogs/mainline/v4.7-
> rc6/buildall.powerpc.ppc64_defconfig.log.passed

I thought about taking this, but I also looked over the code and it
looks correct to me.  This is a semi-hot path in the connection bring
up code, so I'm loathe to put in sizeof(struct sockaddr_storage) * 2 of
needless memory writes.  So, I dropped this patch.  Hopefully, ppc64
compiler will straighten its warnings out soon.

> ---
>  drivers/infiniband/core/cma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/cma.c
> b/drivers/infiniband/core/cma.c
> index a3c9930f1f93..924ac237310b 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -1309,7 +1309,7 @@ static bool validate_net_dev(struct net_device
> *net_dev,
>  static struct net_device *cma_get_net_dev(struct ib_cm_event
> *ib_event,
>  					  const struct cma_req_info
> *req)
>  {
> -	struct sockaddr_storage listen_addr_storage,
> src_addr_storage;
> +	struct sockaddr_storage listen_addr_storage = {},
> src_addr_storage = {};
>  	struct sockaddr *listen_addr = (struct sockaddr
> *)&listen_addr_storage,
>  			*src_addr = (struct sockaddr
> *)&src_addr_storage;
>  	struct net_device *net_dev;

-- 
Doug Ledford <dledford@redhat.com>
              GPG KeyID: 0E572FDD

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Re: [PATCH] infiniband: shut up a maybe-uninitialized warning Doug Ledford <dledford@redhat.com> - 2016-08-02 20:30 +0200
  Re: [PATCH] infiniband: shut up a maybe-uninitialized warning Arnd Bergmann <arnd@arndb.de> - 2016-08-02 22:20 +0200

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