The current driver code performs 512 DMA mappings of a bunch of 
32-byte structures. This is silly, as they are all in contiguous 
memory. Ths patch changes the code to DMA map the entie area
with just one call.

Signed-off-by: Linas Vepstas <[EMAIL PROTECTED]>
Acked-by: Joel Schopp <[EMAIL PROTECTED]>
Cc: James K Lewis <[EMAIL PROTECTED]>
Cc: Arnd Bergmann <[EMAIL PROTECTED]>

----
 drivers/net/spider_net.c |  107 +++++++++++++++++++++++------------------------
 drivers/net/spider_net.h |   16 ++-----
 2 files changed, 59 insertions(+), 64 deletions(-)

Index: linux-2.6.19-git7/drivers/net/spider_net.c
===================================================================
--- linux-2.6.19-git7.orig/drivers/net/spider_net.c     2006-12-06 
15:53:23.000000000 -0600
+++ linux-2.6.19-git7/drivers/net/spider_net.c  2006-12-06 15:56:20.000000000 
-0600
@@ -269,25 +269,6 @@ spider_net_get_descr_status(struct spide
 }
 
 /**
- * spider_net_free_chain - free descriptor chain
- * @card: card structure
- * @chain: address of chain
- *
- */
-static void
-spider_net_free_chain(struct spider_net_card *card,
-                     struct spider_net_descr_chain *chain)
-{
-       struct spider_net_descr *descr;
-
-       for (descr = chain->tail; !descr->bus_addr; descr = descr->next) {
-               pci_unmap_single(card->pdev, descr->bus_addr,
-                                SPIDER_NET_DESCR_SIZE, PCI_DMA_BIDIRECTIONAL);
-               descr->bus_addr = 0;
-       }
-}
-
-/**
  * spider_net_init_chain - links descriptor chain
  * @card: card structure
  * @chain: address of chain
@@ -299,15 +280,15 @@ spider_net_free_chain(struct spider_net_
  *
  * returns 0 on success, <0 on failure
  */
-static int
+static void
 spider_net_init_chain(struct spider_net_card *card,
                       struct spider_net_descr_chain *chain,
                       struct spider_net_descr *start_descr,
+                      dma_addr_t buf,
                       int no)
 {
        int i;
        struct spider_net_descr *descr;
-       dma_addr_t buf;
 
        descr = start_descr;
        memset(descr, 0, sizeof(*descr) * no);
@@ -316,17 +297,12 @@ spider_net_init_chain(struct spider_net_
        for (i=0; i<no; i++, descr++) {
                descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
 
-               buf = pci_map_single(card->pdev, descr,
-                                    SPIDER_NET_DESCR_SIZE,
-                                    PCI_DMA_BIDIRECTIONAL);
-
-               if (pci_dma_mapping_error(buf))
-                       goto iommu_error;
-
                descr->bus_addr = buf;
+               descr->next_descr_addr = 0;
                descr->next = descr + 1;
                descr->prev = descr - 1;
 
+               buf += sizeof(struct spider_net_descr);
        }
        /* do actual circular list */
        (descr-1)->next = start_descr;
@@ -335,17 +311,6 @@ spider_net_init_chain(struct spider_net_
        spin_lock_init(&chain->lock);
        chain->head = start_descr;
        chain->tail = start_descr;
-
-       return 0;
-
-iommu_error:
-       descr = start_descr;
-       for (i=0; i < no; i++, descr++)
-               if (descr->bus_addr)
-                       pci_unmap_single(card->pdev, descr->bus_addr,
-                                        SPIDER_NET_DESCR_SIZE,
-                                        PCI_DMA_BIDIRECTIONAL);
-       return -ENOMEM;
 }
 
 /**
@@ -1652,24 +1617,32 @@ spider_net_open(struct net_device *netde
 {
        struct spider_net_card *card = netdev_priv(netdev);
        struct spider_net_descr *descr;
-       int i, result;
+       int result = -ENOMEM;
 
-       result = -ENOMEM;
-       if (spider_net_init_chain(card, &card->tx_chain, card->descr,
-                                 card->num_tx_desc))
-               goto alloc_tx_failed;
+       card->descr_dma_addr = pci_map_single(card->pdev, card->descr,
+               (card->num_tx_desc+card->num_rx_desc)*sizeof(struct 
spider_net_descr),
+                                    PCI_DMA_BIDIRECTIONAL);
+       if (pci_dma_mapping_error(card->descr_dma_addr))
+               return -ENOMEM;
+
+       spider_net_init_chain(card, &card->tx_chain, card->descr,
+                                 card->descr_dma_addr,
+                                 card->num_tx_desc);
 
        card->low_watermark = NULL;
 
        /* rx_chain is after tx_chain, so offset is descr + tx_count */
-       if (spider_net_init_chain(card, &card->rx_chain,
+       spider_net_init_chain(card, &card->rx_chain,
                                  card->descr + card->num_tx_desc,
-                                 card->num_rx_desc))
-               goto alloc_rx_failed;
+                                 card->descr_dma_addr
+                                       + card->num_tx_desc * sizeof(struct 
spider_net_descr),
+                                 card->num_rx_desc);
 
        descr = card->rx_chain.head;
-       for (i=0; i < card->num_rx_desc; i++, descr++)
+       do {
                descr->next_descr_addr = descr->next->bus_addr;
+               descr = descr->next;
+       } while (descr != card->rx_chain.head);
 
        /* allocate rx skbs */
        if (spider_net_alloc_rx_skbs(card))
@@ -1695,10 +1668,21 @@ spider_net_open(struct net_device *netde
 register_int_failed:
        spider_net_free_rx_chain_contents(card);
 alloc_skbs_failed:
-       spider_net_free_chain(card, &card->rx_chain);
-alloc_rx_failed:
-       spider_net_free_chain(card, &card->tx_chain);
-alloc_tx_failed:
+       descr = card->rx_chain.head;
+       do {
+               descr->bus_addr = 0;
+               descr = descr->next;
+       } while (descr != card->rx_chain.head);
+
+       descr = card->tx_chain.head;
+       do {
+               descr->bus_addr = 0;
+               descr = descr->next;
+       } while (descr != card->tx_chain.head);
+
+       pci_unmap_single(card->pdev, card->descr_dma_addr,
+          (card->num_tx_desc+card->num_rx_desc)*sizeof(struct 
spider_net_descr),
+                        PCI_DMA_BIDIRECTIONAL);
        return result;
 }
 
@@ -1901,6 +1885,7 @@ int
 spider_net_stop(struct net_device *netdev)
 {
        struct spider_net_card *card = netdev_priv(netdev);
+       struct spider_net_descr *descr;
 
        tasklet_kill(&card->rxram_full_tl);
        netif_poll_disable(netdev);
@@ -1924,9 +1909,23 @@ spider_net_stop(struct net_device *netde
 
        /* release chains */
        spider_net_release_tx_chain(card, 1);
+       spider_net_free_rx_chain_contents(card);
+
+       descr = card->rx_chain.head;
+       do {
+               descr->bus_addr = 0;
+               descr = descr->next;
+       } while (descr != card->rx_chain.head);
+
+       descr = card->tx_chain.head;
+       do {
+               descr->bus_addr = 0;
+               descr = descr->next;
+       } while (descr != card->tx_chain.head);
 
-       spider_net_free_chain(card, &card->tx_chain);
-       spider_net_free_chain(card, &card->rx_chain);
+       pci_unmap_single(card->pdev, card->descr_dma_addr,
+             (card->num_tx_desc+card->num_rx_desc)*sizeof(struct 
spider_net_descr),
+                        PCI_DMA_BIDIRECTIONAL);
 
        return 0;
 }
Index: linux-2.6.19-git7/drivers/net/spider_net.h
===================================================================
--- linux-2.6.19-git7.orig/drivers/net/spider_net.h     2006-12-06 
15:53:23.000000000 -0600
+++ linux-2.6.19-git7/drivers/net/spider_net.h  2006-12-06 15:56:20.000000000 
-0600
@@ -397,8 +397,6 @@ struct spider_net_descr_chain {
  * 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,
@@ -437,28 +435,26 @@ struct spider_net_card {
 
        void __iomem *regs;
 
+       int num_rx_desc;
+       int num_tx_desc;
        struct spider_net_descr_chain tx_chain;
        struct spider_net_descr_chain rx_chain;
        struct spider_net_descr *low_watermark;
+       dma_addr_t descr_dma_addr;
 
-       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_options options;
 
+       /* Must be last element in the structure */
        struct spider_net_descr descr[0];
 };
 
-
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