batman-adv: convert bat_priv->tt_crc from atomic_t to uint16_t

In the code we neever need to atomically check and set the bat_priv->tt_crc
field value. It is simply set and read once in different pieces of the code.
Therefore this field can be safely be converted from atomic_t to uint16_t.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

net/batman-adv/bat_iv_ogm.c

@@ -575,8 +575,7 @@ static void bat_iv_ogm_schedule(struct hard_iface *hard_iface,
 			htonl((uint32_t)atomic_read(&hard_iface->seqno));
 
 	batman_ogm_packet->ttvn = atomic_read(&bat_priv->ttvn);
-	batman_ogm_packet->tt_crc = htons((uint16_t)
-						atomic_read(&bat_priv->tt_crc));
+	batman_ogm_packet->tt_crc = htons(bat_priv->tt_crc);
 	if (tt_num_changes >= 0)
 		batman_ogm_packet->tt_num_changes = tt_num_changes;
 

net/batman-adv/send.c

@@ -111,7 +111,7 @@ static int prepare_packet_buffer(struct bat_priv *bat_priv,
 
 	realloc_packet_buffer(hard_iface, new_len);
 
-	atomic_set(&bat_priv->tt_crc, tt_local_crc(bat_priv));
+	bat_priv->tt_crc = tt_local_crc(bat_priv);
 
 	/* reset the sending counter */
 	atomic_set(&bat_priv->tt_ogm_append_cnt, TT_OGM_APPEND_MAX);

net/batman-adv/types.h

@@ -210,7 +210,7 @@ struct bat_priv {
 	spinlock_t vis_list_lock; /* protects vis_info::recv_list */
 	atomic_t num_local_tt;
 	/* Checksum of the local table, recomputed before sending a new OGM */
-	atomic_t tt_crc;
+	uint16_t tt_crc;
 	unsigned char *tt_buff;
 	int16_t tt_buff_len;
 	spinlock_t tt_buff_lock; /* protects tt_buff */