From 021fa22e01d3d0425d3d15df48f523b69a3a11c4 Mon Sep 17 00:00:00 2001 From: Olof Johansson Date: Wed, 22 Aug 2007 09:13:11 -0500 Subject: [PATCH] pasemi_mac: Fix TX ring wrap checking The old logic didn't detect full (tx) ring cases properly, causing overruns and general badness. Clean it up a bit and abstract out the ring size checks, always making sure to leave 1 slot open. Signed-off-by: Olof Johansson Signed-off-by: Jeff Garzik --- drivers/net/pasemi_mac.c | 25 ++++++++++++++----------- drivers/net/pasemi_mac.h | 2 +- 2 files changed, 15 insertions(+), 12 deletions(-) diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c index 4836d405cd5d..dc710a0826b2 100644 --- a/drivers/net/pasemi_mac.c +++ b/drivers/net/pasemi_mac.c @@ -69,6 +69,10 @@ #define RX_DESC_INFO(mac, num) ((mac)->rx->desc_info[(num) & (RX_RING_SIZE-1)]) #define RX_BUFF(mac, num) ((mac)->rx->buffers[(num) & (RX_RING_SIZE-1)]) +#define RING_USED(ring) (((ring)->next_to_fill - (ring)->next_to_clean) \ + & ((ring)->size - 1)) +#define RING_AVAIL(ring) ((ring->size) - RING_USED(ring)) + #define BUF_SIZE 1646 /* 1500 MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */ MODULE_LICENSE("GPL"); @@ -174,6 +178,7 @@ static int pasemi_mac_setup_rx_resources(struct net_device *dev) spin_lock_init(&ring->lock); + ring->size = RX_RING_SIZE; ring->desc_info = kzalloc(sizeof(struct pasemi_mac_buffer) * RX_RING_SIZE, GFP_KERNEL); @@ -253,6 +258,7 @@ static int pasemi_mac_setup_tx_resources(struct net_device *dev) spin_lock_init(&ring->lock); + ring->size = TX_RING_SIZE; ring->desc_info = kzalloc(sizeof(struct pasemi_mac_buffer) * TX_RING_SIZE, GFP_KERNEL); if (!ring->desc_info) @@ -281,7 +287,7 @@ static int pasemi_mac_setup_tx_resources(struct net_device *dev) PAS_DMA_TXCHAN_CFG_UP | PAS_DMA_TXCHAN_CFG_WT(2)); - ring->next_to_use = 0; + ring->next_to_fill = 0; ring->next_to_clean = 0; snprintf(ring->irq_name, sizeof(ring->irq_name), @@ -376,9 +382,7 @@ static void pasemi_mac_replenish_rx_ring(struct net_device *dev) int start = mac->rx->next_to_fill; unsigned int limit, count; - limit = (mac->rx->next_to_clean + RX_RING_SIZE - - mac->rx->next_to_fill) & (RX_RING_SIZE - 1); - + limit = RING_AVAIL(mac->rx); /* Check to see if we're doing first-time setup */ if (unlikely(mac->rx->next_to_clean == 0 && mac->rx->next_to_fill == 0)) limit = RX_RING_SIZE; @@ -562,7 +566,7 @@ restart: spin_lock_irqsave(&mac->tx->lock, flags); start = mac->tx->next_to_clean; - limit = min(mac->tx->next_to_use, start+32); + limit = min(mac->tx->next_to_fill, start+32); count = 0; @@ -1004,14 +1008,13 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev) spin_lock_irqsave(&txring->lock, flags); - if (txring->next_to_clean - txring->next_to_use == TX_RING_SIZE) { + if (RING_AVAIL(txring) <= 1) { spin_unlock_irqrestore(&txring->lock, flags); pasemi_mac_clean_tx(mac); pasemi_mac_restart_tx_intr(mac); spin_lock_irqsave(&txring->lock, flags); - if (txring->next_to_clean - txring->next_to_use == - TX_RING_SIZE) { + if (RING_AVAIL(txring) <= 1) { /* Still no room -- stop the queue and wait for tx * intr when there's room. */ @@ -1020,15 +1023,15 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev) } } - dp = &TX_DESC(mac, txring->next_to_use); - info = &TX_DESC_INFO(mac, txring->next_to_use); + dp = &TX_DESC(mac, txring->next_to_fill); + info = &TX_DESC_INFO(mac, txring->next_to_fill); dp->mactx = mactx; dp->ptr = ptr; info->dma = map; info->skb = skb; - txring->next_to_use++; + txring->next_to_fill++; mac->stats.tx_packets++; mac->stats.tx_bytes += skb->len; diff --git a/drivers/net/pasemi_mac.h b/drivers/net/pasemi_mac.h index fbbc17a31db7..c5b0adbc182e 100644 --- a/drivers/net/pasemi_mac.h +++ b/drivers/net/pasemi_mac.h @@ -31,7 +31,7 @@ struct pasemi_mac_txring { struct pas_dma_xct_descr *desc; dma_addr_t dma; unsigned int size; - unsigned int next_to_use; + unsigned int next_to_fill; unsigned int next_to_clean; struct pasemi_mac_buffer *desc_info; char irq_name[10]; /* "eth%d tx" */ -- 2.20.1