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Commit cc6a7aab authored by Arnd Bergmann's avatar Arnd Bergmann Committed by J. Bruce Fields
Browse files

sunrpc: avoid warning in gss_key_timeout 



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: default avatarArnd Bergmann <arnd@arndb.de>
Fixes: c5e6aecd ("sunrpc: fix RCU handling of gc_ctx field")
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 0d0f4aab

net/sunrpc/auth_gss/auth_gss.c

+6 −7
Original line number Diff line number Diff line
@@ -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