Staging: batman-adv: receive packets directly using skbs

This patch removes the (ugly and racy) packet receiving thread and the
kernel socket usage. Instead, packets are received directly by registering
the ethernet type and handling skbs instead of self-allocated buffers.

Some consequences and comments:

 * we don't copy the payload data when forwarding/sending/receiving data
   anymore. This should boost performance.
 * packets from/to different interfaces can be (theoretically) processed
   simultaneously. Only the big originator hash lock might be in the way.
 * no more polling or sleeping/wakeup/scheduling issues when receiving
   packets
 * this might introduce new race conditions.
 * aggregation and vis code still use packet buffers and are not (yet)
   converted.
 * all spinlocks were converted to irqsave/restore versions to solve
   some lifelock issues when preempted. This might be overkill, some
   of these locks might be reverted later.
 * skb copies are only done if neccesary to avoid overhead

performance differences:

 * we made some "benchmarks" with intel laptops.
 * bandwidth on Gigabit Ethernet increased from ~500 MBit/s to ~920 MBit/s
 * ping latency decresed from ~2ms to ~0.2 ms

I did some tests on my 9 node qemu environment and could confirm that
usual sending/receiving, forwarding, vis, batctl ping etc works.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Acked-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Acked-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/staging/batman-adv/send.h b/drivers/staging/batman-adv/send.h
index 59d500917a3..5fc6f3417cb 100644
--- a/drivers/staging/batman-adv/send.h
+++ b/drivers/staging/batman-adv/send.h
@@ -22,6 +22,9 @@
 #include "types.h"
 
 void send_own_packet_work(struct work_struct *work);
+int send_skb_packet(struct sk_buff *skb,
+				struct batman_if *batman_if,
+				uint8_t *dst_addr);
 void send_raw_packet(unsigned char *pack_buff, int pack_buff_len,
 		     struct batman_if *batman_if, uint8_t *dst_addr);
 void schedule_own_packet(struct batman_if *batman_if);
@@ -30,7 +33,7 @@ void schedule_forward_packet(struct orig_node *orig_node,
 			     struct batman_packet *batman_packet,
 			     uint8_t directlink, int hna_buff_len,
 			     struct batman_if *if_outgoing);
-void add_bcast_packet_to_list(unsigned char *packet_buff, int packet_len);
+void add_bcast_packet_to_list(struct sk_buff *skb);
 void send_outstanding_bcast_packet(struct work_struct *work);
 void send_outstanding_bat_packet(struct work_struct *work);
 void purge_outstanding_packets(void);