tcp: kill pointless urg_mode

It all started from me noticing that this urgent check in
tcp_clean_rtx_queue is unnecessarily inside the loop. Then
I took a longer look to it and found out that the users of
urg_mode can trivially do without, well almost, there was
one gotcha.

Bonus: those funny people who use urg with >= 2^31 write_seq -
snd_una could now rejoice too (that's the only purpose for the
between being there, otherwise a simple compare would have done
the thing). Not that I assume that the rest of the tcp code
happily lives with such mind-boggling numbers :-). Alas, it
turned out to be impossible to set wmem to such numbers anyway,
yes I really tried a big sendfile after setting some wmem but
nothing happened :-). ...Tcp_wmem is int and so is sk_sndbuf...
So I hacked a bit variable to long and found out that it seems
to work... :-)

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 7672906..fe77e14 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -312,8 +312,11 @@
 	u32	retrans_out;	/* Retransmitted packets out		*/
 
 	u16	urg_data;	/* Saved octet of OOB data and control flags */
-	u8	urg_mode;	/* In urgent mode		*/
 	u8	ecn_flags;	/* ECN status bits.			*/
+	u8	reordering;	/* Packet reordering metric.		*/
+	u32	snd_up;		/* Urgent pointer		*/
+
+	u8	keepalive_probes; /* num of allowed keep alive probes	*/
 /*
  *      Options received (usually on last packet, some only on SYN packets).
  */
@@ -361,8 +364,6 @@
 
 	u32	lost_retrans_low;	/* Sent seq after any rxmit (lowest) */
 
-	u8	reordering;	/* Packet reordering metric.		*/
-	u8	keepalive_probes; /* num of allowed keep alive probes	*/
 	u32	prior_ssthresh; /* ssthresh saved at recovery start	*/
 	u32	high_seq;	/* snd_nxt at onset of congestion	*/
 
@@ -374,8 +375,6 @@
 	u32	total_retrans;	/* Total retransmits for entire connection */
 
 	u32	urg_seq;	/* Seq of received urgent pointer */
-	u32	snd_up;		/* Urgent pointer		*/
-
 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */