mac80211: Fix clang warning about constant operand in logical operation

commit 93f56de259376d7e4fff2b2d104082e1fa66e237 upstream.

When clang detects a non-boolean constant in a logical operation it
generates a 'constant-logical-operand' warning. In
ieee80211_try_rate_control_ops_get() the result of strlen(<const str>)
is used in a logical operation, clang resolves the expression to an
(integer) constant at compile time when clang's builtin strlen function
is used.

Change the condition to check for strlen() > 0 to make the constant
operand boolean and thus avoid the warning.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index dbceb42c2a8e0417ac952c867bdf7f0058fc137a..e6096dfd02105223e100898bc71d14bc8d774e4f 100644 (file)
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -173,9 +173,11 @@ ieee80211_rate_control_ops_get(const char *name)
                /* try default if specific alg requested but not found */
                ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
 
-       /* try built-in one if specific alg requested but not found */
-       if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
+       /* Note: check for > 0 is intentional to avoid clang warning */
+       if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
+               /* try built-in one if specific alg requested but not found */
                ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
+
        kernel_param_unlock(THIS_MODULE);
 
        return ops;