Spidernet DMA coalescing

The current driver code performs 512 DMA mappings of a bunch of
32-byte ring descriptor structures. This is silly, as they are
all in contiguous memory. This patch changes the code to
dma_map_coherent() each rx/tx ring as a whole.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: James K Lewis <jklewis@us.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/spider_net.h b/drivers/net/spider_net.h
index 3e196df..4b76ef95 100644
--- a/drivers/net/spider_net.h
+++ b/drivers/net/spider_net.h
@@ -378,6 +378,9 @@
 	spinlock_t lock;
 	struct spider_net_descr *head;
 	struct spider_net_descr *tail;
+	struct spider_net_descr *ring;
+	int num_desc;
+	dma_addr_t dma_addr;
 };
 
 /* descriptor data_status bits */
@@ -397,8 +400,6 @@
  * 701b8000 would be correct, but every packets gets that flag */
 #define SPIDER_NET_DESTROY_RX_FLAGS	0x700b8000
 
-#define SPIDER_NET_DESCR_SIZE		32
-
 /* this will be bigger some time */
 struct spider_net_options {
 	int rx_csum; /* for rx: if 0 ip_summed=NONE,
@@ -441,25 +442,17 @@
 	struct spider_net_descr_chain rx_chain;
 	struct spider_net_descr *low_watermark;
 
-	struct net_device_stats netdev_stats;
-
-	struct spider_net_options options;
-
-	spinlock_t intmask_lock;
 	struct tasklet_struct rxram_full_tl;
 	struct timer_list tx_timer;
-
 	struct work_struct tx_timeout_task;
 	atomic_t tx_timeout_task_counter;
 	wait_queue_head_t waitq;
 
 	/* for ethtool */
 	int msg_enable;
-	int num_rx_desc;
-	int num_tx_desc;
+	struct net_device_stats netdev_stats;
 	struct spider_net_extra_stats spider_stats;
-
-	struct spider_net_descr descr[0];
+	struct spider_net_options options;
 };
 
 #define pr_err(fmt,arg...) \