Return-Path: Received: from mout.kundenserver.de ([212.227.17.10]:51409 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752831AbbJIOOU (ORCPT ); Fri, 9 Oct 2015 10:14:20 -0400 From: Arnd Bergmann To: Trond Myklebust , linux-nfs@vger.kernel.org Cc: Anna Schumaker , "J. Bruce Fields" , Jeff Layton , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] sunrpc: avoid warning in gss_key_timeout Date: Fri, 09 Oct 2015 16:13:45 +0200 Message-ID: <6995148.OQIKcAcqHW@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-nfs-owner@vger.kernel.org List-ID: The gss_key_timeout() function causes a harmless warning in some configurations, e.g. ARM imx_v6_v7_defconfig with gcc-5.2, if the compiler cannot figure out the state of the 'expire' variable across an rcu_read_unlock(): net/sunrpc/auth_gss/auth_gss.c: In function 'gss_key_timeout': net/sunrpc/auth_gss/auth_gss.c:1422:211: warning: 'expire' may be used uninitialized in this function [-Wmaybe-uninitialized] To avoid this warning without adding a bogus initialization, this rewrites the function so the comparison is done inside of the critical section. As a side-effect, it also becomes slightly easier to understand because the implementation now more closely resembles the comment above it. Signed-off-by: Arnd Bergmann Fixes: c5e6aecd034e7 ("sunrpc: fix RCU handling of gc_ctx field") diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index dace13d7638e..799e65b944b9 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -1411,17 +1411,16 @@ gss_key_timeout(struct rpc_cred *rc) { struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base); struct gss_cl_ctx *ctx; - unsigned long now = jiffies; - unsigned long expire; + unsigned long timeout = jiffies + (gss_key_expire_timeo * HZ); + int ret = 0; rcu_read_lock(); ctx = rcu_dereference(gss_cred->gc_ctx); - if (ctx) - expire = ctx->gc_expiry - (gss_key_expire_timeo * HZ); + if (!ctx || time_after(timeout, ctx->gc_expiry)) + ret = -EACCES; rcu_read_unlock(); - if (!ctx || time_after(now, expire)) - return -EACCES; - return 0; + + return ret; } static int