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>
This commit is contained in:
Linas Vepstas
Jeff Garzik
parent
834324687d
commit
d4ed8f8d1f
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@ -280,72 +280,67 @@ spider_net_free_chain(struct spider_net_card *card,
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{
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struct spider_net_descr *descr;
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for (descr = chain->tail; !descr->bus_addr; descr = descr->next) {
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pci_unmap_single(card->pdev, descr->bus_addr,
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SPIDER_NET_DESCR_SIZE, PCI_DMA_BIDIRECTIONAL);
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descr = chain->ring;
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do {
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descr->bus_addr = 0;
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}
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descr->next_descr_addr = 0;
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descr = descr->next;
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} while (descr != chain->ring);
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dma_free_coherent(&card->pdev->dev, chain->num_desc,
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chain->ring, chain->dma_addr);
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}
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/**
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* spider_net_init_chain - links descriptor chain
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* spider_net_init_chain - alloc and link descriptor chain
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* @card: card structure
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* @chain: address of chain
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* @start_descr: address of descriptor array
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* @no: number of descriptors
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*
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* we manage a circular list that mirrors the hardware structure,
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* We manage a circular list that mirrors the hardware structure,
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* except that the hardware uses bus addresses.
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*
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* returns 0 on success, <0 on failure
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* Returns 0 on success, <0 on failure
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*/
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static int
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spider_net_init_chain(struct spider_net_card *card,
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struct spider_net_descr_chain *chain,
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struct spider_net_descr *start_descr,
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int no)
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struct spider_net_descr_chain *chain)
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{
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int i;
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struct spider_net_descr *descr;
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dma_addr_t buf;
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size_t alloc_size;
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descr = start_descr;
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memset(descr, 0, sizeof(*descr) * no);
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alloc_size = chain->num_desc * sizeof (struct spider_net_descr);
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/* set up the hardware pointers in each descriptor */
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for (i=0; i<no; i++, descr++) {
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chain->ring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
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&chain->dma_addr, GFP_KERNEL);
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if (!chain->ring)
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return -ENOMEM;
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descr = chain->ring;
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memset(descr, 0, alloc_size);
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/* Set up the hardware pointers in each descriptor */
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buf = chain->dma_addr;
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for (i=0; i < chain->num_desc; i++, descr++) {
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descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
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buf = pci_map_single(card->pdev, descr,
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SPIDER_NET_DESCR_SIZE,
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PCI_DMA_BIDIRECTIONAL);
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if (pci_dma_mapping_error(buf))
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goto iommu_error;
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descr->bus_addr = buf;
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descr->next_descr_addr = 0;
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descr->next = descr + 1;
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descr->prev = descr - 1;
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buf += sizeof(struct spider_net_descr);
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}
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/* do actual circular list */
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(descr-1)->next = start_descr;
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start_descr->prev = descr-1;
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(descr-1)->next = chain->ring;
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chain->ring->prev = descr-1;
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spin_lock_init(&chain->lock);
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chain->head = start_descr;
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chain->tail = start_descr;
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chain->head = chain->ring;
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chain->tail = chain->ring;
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return 0;
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iommu_error:
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descr = start_descr;
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for (i=0; i < no; i++, descr++)
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if (descr->bus_addr)
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pci_unmap_single(card->pdev, descr->bus_addr,
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SPIDER_NET_DESCR_SIZE,
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PCI_DMA_BIDIRECTIONAL);
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return -ENOMEM;
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}
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/**
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@ -707,7 +702,7 @@ spider_net_set_low_watermark(struct spider_net_card *card)
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}
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/* If TX queue is short, don't even bother with interrupts */
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if (cnt < card->num_tx_desc/4)
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if (cnt < card->tx_chain.num_desc/4)
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return cnt;
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/* Set low-watermark 3/4th's of the way into the queue. */
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@ -1652,26 +1647,25 @@ spider_net_open(struct net_device *netdev)
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{
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struct spider_net_card *card = netdev_priv(netdev);
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struct spider_net_descr *descr;
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int i, result;
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int result;
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result = -ENOMEM;
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if (spider_net_init_chain(card, &card->tx_chain, card->descr,
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card->num_tx_desc))
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result = spider_net_init_chain(card, &card->tx_chain);
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if (result)
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goto alloc_tx_failed;
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card->low_watermark = NULL;
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/* rx_chain is after tx_chain, so offset is descr + tx_count */
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if (spider_net_init_chain(card, &card->rx_chain,
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card->descr + card->num_tx_desc,
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card->num_rx_desc))
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result = spider_net_init_chain(card, &card->rx_chain);
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if (result)
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goto alloc_rx_failed;
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descr = card->rx_chain.head;
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for (i=0; i < card->num_rx_desc; i++, descr++)
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/* Make a ring of of bus addresses */
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descr = card->rx_chain.ring;
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do {
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descr->next_descr_addr = descr->next->bus_addr;
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descr = descr->next;
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} while (descr != card->rx_chain.ring);
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/* allocate rx skbs */
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/* Allocate rx skbs */
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if (spider_net_alloc_rx_skbs(card))
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goto alloc_skbs_failed;
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@ -1924,6 +1918,7 @@ spider_net_stop(struct net_device *netdev)
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/* release chains */
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spider_net_release_tx_chain(card, 1);
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spider_net_free_rx_chain_contents(card);
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spider_net_free_rx_chain_contents(card);
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@ -2057,8 +2052,8 @@ spider_net_setup_netdev(struct spider_net_card *card)
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card->options.rx_csum = SPIDER_NET_RX_CSUM_DEFAULT;
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card->num_tx_desc = tx_descriptors;
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card->num_rx_desc = rx_descriptors;
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card->tx_chain.num_desc = tx_descriptors;
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card->rx_chain.num_desc = rx_descriptors;
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spider_net_setup_netdev_ops(netdev);
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@ -2107,12 +2102,8 @@ spider_net_alloc_card(void)
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{
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struct net_device *netdev;
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struct spider_net_card *card;
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size_t alloc_size;
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alloc_size = sizeof (*card) +
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sizeof (struct spider_net_descr) * rx_descriptors +
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sizeof (struct spider_net_descr) * tx_descriptors;
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netdev = alloc_etherdev(alloc_size);
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netdev = alloc_etherdev(sizeof(struct spider_net_card));
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if (!netdev)
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return NULL;
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@ -378,6 +378,9 @@ struct spider_net_descr_chain {
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spinlock_t lock;
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struct spider_net_descr *head;
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struct spider_net_descr *tail;
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struct spider_net_descr *ring;
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int num_desc;
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dma_addr_t dma_addr;
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};
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/* descriptor data_status bits */
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@ -397,8 +400,6 @@ struct spider_net_descr_chain {
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* 701b8000 would be correct, but every packets gets that flag */
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#define SPIDER_NET_DESTROY_RX_FLAGS 0x700b8000
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#define SPIDER_NET_DESCR_SIZE 32
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/* this will be bigger some time */
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struct spider_net_options {
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int rx_csum; /* for rx: if 0 ip_summed=NONE,
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@ -441,25 +442,17 @@ struct spider_net_card {
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struct spider_net_descr_chain rx_chain;
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struct spider_net_descr *low_watermark;
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struct net_device_stats netdev_stats;
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struct spider_net_options options;
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spinlock_t intmask_lock;
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struct tasklet_struct rxram_full_tl;
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struct timer_list tx_timer;
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struct work_struct tx_timeout_task;
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atomic_t tx_timeout_task_counter;
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wait_queue_head_t waitq;
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/* for ethtool */
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int msg_enable;
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int num_rx_desc;
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int num_tx_desc;
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struct net_device_stats netdev_stats;
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struct spider_net_extra_stats spider_stats;
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struct spider_net_descr descr[0];
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struct spider_net_options options;
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};
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#define pr_err(fmt,arg...) \
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@ -158,9 +158,9 @@ spider_net_ethtool_get_ringparam(struct net_device *netdev,
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struct spider_net_card *card = netdev->priv;
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ering->tx_max_pending = SPIDER_NET_TX_DESCRIPTORS_MAX;
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ering->tx_pending = card->num_tx_desc;
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ering->tx_pending = card->tx_chain.num_desc;
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ering->rx_max_pending = SPIDER_NET_RX_DESCRIPTORS_MAX;
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ering->rx_pending = card->num_rx_desc;
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ering->rx_pending = card->rx_chain.num_desc;
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}
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static int spider_net_get_stats_count(struct net_device *netdev)
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