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Commit 021fa22e authored by Olof Johansson's avatar Olof Johansson Committed by David S. Miller
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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: default avatarOlof Johansson <olof@lixom.net>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 02df6cfa

drivers/net/pasemi_mac.c

+14 −11
Original line number Diff line number Diff line
@@ -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 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac) 
	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;

drivers/net/pasemi_mac.h

+1 −1
Original line number Diff line number Diff line
@@ -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" */