[IPV4]: Add raw drops counter.

Add raw drops counter for IPv4 in /proc/net/raw .

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index 6e1542d..f5b6437 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -145,7 +145,8 @@
   *	@sk_forward_alloc: space allocated forward
   *	@sk_allocation: allocation mode
   *	@sk_sndbuf: size of send buffer in bytes
-  *	@sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE, %SO_OOBINLINE settings
+  *	@sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
+  *		   %SO_OOBINLINE settings
   *	@sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
   *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
   *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
@@ -153,9 +154,12 @@
   *	@sk_backlog: always used with the per-socket spinlock held
   *	@sk_callback_lock: used with the callbacks in the end of this struct
   *	@sk_error_queue: rarely used
-  *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt, IPV6_ADDRFORM for instance)
+  *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
+  *			  IPV6_ADDRFORM for instance)
   *	@sk_err: last error
-  *	@sk_err_soft: errors that don't cause failure but are the cause of a persistent failure not just 'timed out'
+  *	@sk_err_soft: errors that don't cause failure but are the cause of a
+  *		      persistent failure not just 'timed out'
+  *	@sk_drops: raw drops counter
   *	@sk_ack_backlog: current listen backlog
   *	@sk_max_ack_backlog: listen backlog set in listen()
   *	@sk_priority: %SO_PRIORITY setting
@@ -239,6 +243,7 @@
 	rwlock_t		sk_callback_lock;
 	int			sk_err,
 				sk_err_soft;
+	atomic_t		sk_drops;
 	unsigned short		sk_ack_backlog;
 	unsigned short		sk_max_ack_backlog;
 	__u32			sk_priority;