[PATCH] mac80211: make CALL_TXH a statement

[PATCH] mac80211: make CALL_TXH a statement

[Johannes Berg]

The multi-line code in this macro wasn't wrapped
in do {} while (0) so we cannot use it in an if()
branch safely in the future -- fix that.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
---
 net/mac80211/tx.c |   34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

--- wireless-testing.orig/net/mac80211/tx.c	2009-10-06 14:57:11.000000000 +0200
+++ wireless-testing/net/mac80211/tx.c	2009-10-06 14:57:39.000000000 +0200
@@ -1201,23 +1201,25 @@ static int invoke_tx_handlers(struct iee
 	struct sk_buff *skb = tx->skb;
 	ieee80211_tx_result res = TX_DROP;
 
-#define CALL_TXH(txh)		\
-	res = txh(tx);		\
-	if (res != TX_CONTINUE)	\
-		goto txh_done;
-
-	CALL_TXH(ieee80211_tx_h_check_assoc)
-	CALL_TXH(ieee80211_tx_h_ps_buf)
-	CALL_TXH(ieee80211_tx_h_select_key)
-	CALL_TXH(ieee80211_tx_h_michael_mic_add)
-	CALL_TXH(ieee80211_tx_h_rate_ctrl)
-	CALL_TXH(ieee80211_tx_h_misc)
-	CALL_TXH(ieee80211_tx_h_sequence)
-	CALL_TXH(ieee80211_tx_h_fragment)
+#define CALL_TXH(txh) \
+	do {				\
+		res = txh(tx);		\
+		if (res != TX_CONTINUE)	\
+			goto txh_done;	\
+	} while (0)
+
+	CALL_TXH(ieee80211_tx_h_check_assoc);
+	CALL_TXH(ieee80211_tx_h_ps_buf);
+	CALL_TXH(ieee80211_tx_h_select_key);
+	CALL_TXH(ieee80211_tx_h_michael_mic_add);
+	CALL_TXH(ieee80211_tx_h_rate_ctrl);
+	CALL_TXH(ieee80211_tx_h_misc);
+	CALL_TXH(ieee80211_tx_h_sequence);
+	CALL_TXH(ieee80211_tx_h_fragment);
 	/* handlers after fragment must be aware of tx info fragmentation! */
-	CALL_TXH(ieee80211_tx_h_stats)
-	CALL_TXH(ieee80211_tx_h_encrypt)
-	CALL_TXH(ieee80211_tx_h_calculate_duration)
+	CALL_TXH(ieee80211_tx_h_stats);
+	CALL_TXH(ieee80211_tx_h_encrypt);
+	CALL_TXH(ieee80211_tx_h_calculate_duration);
 #undef CALL_TXH
 
  txh_done:

Re: [PATCH] mac80211: make CALL_TXH a statement

[John W. Linville]

On Thu, Oct 29, 2009 at 08:43:48AM +0100, Johannes Berg wrote:
> The multi-line code in this macro wasn't wrapped
> in do {} while (0) so we cannot use it in an if()
> branch safely in the future -- fix that.
> 
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

do {...} while (0) won't work for that either, right?  You need
({...}) instead if you want to return a value.  Is that what you want?

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.

Re: [PATCH] mac80211: make CALL_TXH a statement

[Johannes Berg]

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On Fri, 2009-10-30 at 15:11 -0400, John W. Linville wrote:
> On Thu, Oct 29, 2009 at 08:43:48AM +0100, Johannes Berg wrote:
> > The multi-line code in this macro wasn't wrapped
> > in do {} while (0) so we cannot use it in an if()
> > branch safely in the future -- fix that.
> > 
> > Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> 
> do {...} while (0) won't work for that either, right?  You need
> ({...}) instead if you want to return a value.  Is that what you want?

No, I just want to be able to do

if (...)
	CALL_TXH(...)

johannes

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Re: [PATCH] mac80211: make CALL_TXH a statement

[John W. Linville]

On Fri, Oct 30, 2009 at 09:43:47PM +0100, Johannes Berg wrote:
> On Fri, 2009-10-30 at 15:11 -0400, John W. Linville wrote:
> > On Thu, Oct 29, 2009 at 08:43:48AM +0100, Johannes Berg wrote:
> > > The multi-line code in this macro wasn't wrapped
> > > in do {} while (0) so we cannot use it in an if()
> > > branch safely in the future -- fix that.
> > > 
> > > Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> > 
> > do {...} while (0) won't work for that either, right?  You need
> > ({...}) instead if you want to return a value.  Is that what you want?
> 
> No, I just want to be able to do
> 
> if (...)
> 	CALL_TXH(...)

Oh, I see -- I misunderstood you.

John
-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.