[ 057/102] net: mac802154: comparision issue of type cast, finding by EXTRA_CFLAGS=-W

[Greg Kroah-Hartman]

3.9-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Chen Gang <gang.chen@xxxxxxxxxxx>

[ Upstream commit 2c1bbbffa0b644fab4f91878cde0c2e8f52e2dcc ]

Change MAC802154_CHAN_NONE from ~(u8)0 to 0xff, or the comparison in
mac802154_wpan_xmit() for ``chan == MAC802154_CHAN_NONE'' will not
succeed.

This bug can be boiled down to ``u8 foo = 0xff; if (foo == ~(u8)0)
[...] else [...]'' where the condition will always take the else
branch.

Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/mac802154/mac802154.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/mac802154/mac802154.h
+++ b/net/mac802154/mac802154.h
@@ -90,7 +90,7 @@ struct mac802154_sub_if_data {
 
 #define MAC802154_MAX_XMIT_ATTEMPTS	3
 
-#define MAC802154_CHAN_NONE		(~(u8)0) /* No channel is assigned */
+#define MAC802154_CHAN_NONE		0xff /* No channel is assigned */
 
 extern struct ieee802154_reduced_mlme_ops mac802154_mlme_reduced;
 extern struct ieee802154_mlme_ops mac802154_mlme_wpan;


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