[PATCH] drivers/net/*: use time_after() and friends

They deal with wrapping correctly and are nicer to read.  Also make
jiffies-holding variables unsigned long.

Signed-off-by: Marcelo Feitoza Parisi <marcelo@feitoza.com.br>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c
index aa6540b..23659fd 100644
--- a/drivers/net/ppp_async.c
+++ b/drivers/net/ppp_async.c
@@ -30,6 +30,7 @@
 #include <linux/ppp_channel.h>
 #include <linux/spinlock.h>
 #include <linux/init.h>
+#include <linux/jiffies.h>
 #include <asm/uaccess.h>
 #include <asm/string.h>
 
@@ -570,7 +571,7 @@
 		 * character if necessary.
 		 */
 		if (islcp || flag_time == 0
-		    || jiffies - ap->last_xmit >= flag_time)
+		    || time_after_eq(jiffies, ap->last_xmit + flag_time))
 			*buf++ = PPP_FLAG;
 		ap->last_xmit = jiffies;
 		fcs = PPP_INITFCS;