net: wireless: ath9k: avoid possible NULL pointer dereference

Code in ath9k_hw_set_clockrate function indicates that ah->curchan
(and thus chan local variable) may be NULL.  If that is indeed the
case, IS_CHAN_HT40(chan) check has to be performed only in branch
where chan is not NULL.  Moving the code under already existing
if condition fixes this issue.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 54b04155e43b..8918035da3a3 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -146,10 +146,9 @@ static void ath9k_hw_set_clockrate(struct ath_hw *ah)
         else
                 clockrate = ATH9K_CLOCK_RATE_5GHZ_OFDM;
 
-        if (IS_CHAN_HT40(chan))
-                clockrate *= 2;
-
-        if (ah->curchan) {
+        if (chan) {
+                if (IS_CHAN_HT40(chan))
+                        clockrate *= 2;
                 if (IS_CHAN_HALF_RATE(chan))
                         clockrate /= 2;
                 if (IS_CHAN_QUARTER_RATE(chan))