[Cbe-oss-dev] [PATCH 3/10] ps3: tx descriptor handling cleanup
Masakazu Mokuno
mokuno at sm.sony.co.jp
Fri Jul 20 18:24:56 EST 2007
gelic: TX descriptor handling cleanup
- Emitted return value of NETDEV_TX_LOCKED when DMA map or kick
failure.
Now it would free the skb, update drop packet statistics
and return OK. Requested from Jeff Garzik.
- Enable tx queue if number of free descriptors are more than 2
- Fixed descriptor leak if dma map for second descriptor failed
- Stopped calling xmit handler from interrupt handler in order
to recheck tx queue. Instead, call appropriate helper functions.
Signed-off-by: Masakazu Mokuno <mokuno at sm.sony.co.jp>
---
drivers/net/ps3_gelic_net.c | 124 +++++++++++++++++++++++++-------------------
1 file changed, 71 insertions(+), 53 deletions(-)
--- a/drivers/net/ps3_gelic_net.c
+++ b/drivers/net/ps3_gelic_net.c
@@ -408,22 +408,25 @@ static void gelic_net_release_tx_chain(s
break;
case GELIC_NET_DESCR_COMPLETE:
- card->netdev_stats.tx_packets++;
- card->netdev_stats.tx_bytes +=
- tx_chain->tail->skb->len;
+ if (tx_chain->tail->skb) {
+ card->netdev_stats.tx_packets++;
+ card->netdev_stats.tx_bytes +=
+ tx_chain->tail->skb->len;
+ }
break;
case GELIC_NET_DESCR_CARDOWNED:
/* pending tx request */
default:
/* any other value (== GELIC_NET_DESCR_NOT_IN_USE) */
- goto out;
+ if (!stop)
+ goto out;
}
gelic_net_release_tx_descr(card, tx_chain->tail);
- release = 1;
+ release ++;
}
out:
- if (!stop && release)
+ if (!stop && (2 < release))
netif_wake_queue(card->netdev);
}
@@ -660,19 +663,21 @@ static int gelic_net_prepare_tx_descr_v(
{
dma_addr_t buf[2];
unsigned int vlan_len;
+ struct gelic_net_descr *sec_descr = descr->next;
if (skb->len < GELIC_NET_VLAN_POS)
return -EINVAL;
- memcpy(&descr->vlan, skb->data, GELIC_NET_VLAN_POS);
+ vlan_len = GELIC_NET_VLAN_POS;
+ memcpy(&descr->vlan, skb->data, vlan_len);
if (card->vlan_index != -1) {
+ /* internal vlan tag used */
descr->vlan.h_vlan_proto = htons(ETH_P_8021Q); /* vlan 0x8100*/
descr->vlan.h_vlan_TCI = htons(card->vlan_id[card->vlan_index]);
- vlan_len = GELIC_NET_VLAN_POS + VLAN_HLEN; /* VLAN_HLEN=4 */
- } else
- vlan_len = GELIC_NET_VLAN_POS; /* no vlan tag */
+ vlan_len += VLAN_HLEN; /* added for above two lines */
+ }
- /* first descr */
+ /* map data area */
buf[0] = dma_map_single(ctodev(card), &descr->vlan,
vlan_len, DMA_TO_DEVICE);
@@ -683,20 +688,6 @@ static int gelic_net_prepare_tx_descr_v(
return -ENOMEM;
}
- descr->buf_addr = buf[0];
- descr->buf_size = vlan_len;
- descr->skb = skb; /* not used */
- descr->data_status = 0;
- gelic_net_set_txdescr_cmdstat(descr, skb, 1); /* not the frame end */
-
- /* second descr */
- card->tx_chain.head = card->tx_chain.head->next;
- descr->next_descr_addr = descr->next->bus_addr;
- descr = descr->next;
- if (gelic_net_get_descr_status(descr) != GELIC_NET_DESCR_NOT_IN_USE)
- /* XXX will be removed */
- dev_err(ctodev(card), "descr is not free!\n");
-
buf[1] = dma_map_single(ctodev(card), skb->data + GELIC_NET_VLAN_POS,
skb->len - GELIC_NET_VLAN_POS,
DMA_TO_DEVICE);
@@ -711,13 +702,24 @@ static int gelic_net_prepare_tx_descr_v(
return -ENOMEM;
}
- descr->buf_addr = buf[1];
- descr->buf_size = skb->len - GELIC_NET_VLAN_POS;
- descr->skb = skb;
+ /* first descr */
+ descr->buf_addr = buf[0];
+ descr->buf_size = vlan_len;
+ descr->skb = NULL; /* not used */
descr->data_status = 0;
- descr->next_descr_addr = 0; /* terminate hw descr */
- gelic_net_set_txdescr_cmdstat(descr, skb, 0);
+ descr->next_descr_addr = descr->next->bus_addr;
+ gelic_net_set_txdescr_cmdstat(descr, skb, 1); /* not the frame end */
+ /* second descr */
+ sec_descr->buf_addr = buf[1];
+ sec_descr->buf_size = skb->len - GELIC_NET_VLAN_POS;
+ sec_descr->skb = skb;
+ sec_descr->data_status = 0;
+ sec_descr->next_descr_addr = 0; /* terminate hw descr */
+ gelic_net_set_txdescr_cmdstat(sec_descr, skb, 0);
+
+ /* bump free descriptor pointer */
+ card->tx_chain.head = sec_descr->next;
return 0;
}
@@ -730,7 +732,7 @@ static int gelic_net_prepare_tx_descr_v(
static int gelic_net_kick_txdma(struct gelic_net_card *card,
struct gelic_net_descr *descr)
{
- int status = -ENXIO;
+ int status = 0;
int count = 10;
if (card->tx_dma_progress)
@@ -764,47 +766,62 @@ static int gelic_net_kick_txdma(struct g
static int gelic_net_xmit(struct sk_buff *skb, struct net_device *netdev)
{
struct gelic_net_card *card = netdev_priv(netdev);
- struct gelic_net_descr *descr = NULL;
+ struct gelic_net_descr *descr;
int result;
unsigned long flags;
spin_lock_irqsave(&card->tx_dma_lock, flags);
gelic_net_release_tx_chain(card, 0);
- if (!skb)
- goto kick;
+
descr = gelic_net_get_next_tx_descr(card);
if (!descr) {
+ /*
+ * no more descriptors free
+ */
netif_stop_queue(netdev);
spin_unlock_irqrestore(&card->tx_dma_lock, flags);
return NETDEV_TX_BUSY;
}
- result = gelic_net_prepare_tx_descr_v(card, descr, skb);
-
- if (result)
- goto error;
- card->tx_chain.head = card->tx_chain.head->next;
-
- if (descr->prev)
- descr->prev->next_descr_addr = descr->bus_addr;
-kick:
+ result = gelic_net_prepare_tx_descr_v(card, descr, skb);
+ if (result) {
+ /*
+ * DMA map failed. As chanses are that failure
+ * would continue, just release skb and return
+ */
+ card->netdev_stats.tx_dropped++;
+ dev_kfree_skb_any(skb);
+ spin_unlock_irqrestore(&card->tx_dma_lock, flags);
+ return NETDEV_TX_OK;
+ }
+ /*
+ * link this prepared descriptor to previous one
+ * to achieve high performance
+ */
+ descr->prev->next_descr_addr = descr->bus_addr;
/*
* as hardware descriptor is modified in the above lines,
* ensure that the hardware sees it
*/
wmb();
- if (gelic_net_kick_txdma(card, card->tx_chain.tail))
- goto error;
+ if (gelic_net_kick_txdma(card, descr)) {
+ /*
+ * kick failed.
+ * release descriptors which were just prepared
+ */
+ card->netdev_stats.tx_dropped++;
+ gelic_net_release_tx_descr(card, descr);
+ gelic_net_release_tx_descr(card, descr->next);
+ card->tx_chain.tail = descr->next->next;
+ dev_info(ctodev(card), "%s: kick failure\n", __func__);
+ } else {
+ /* OK, DMA started/reserved */
+ netdev->trans_start = jiffies;
+ }
- netdev->trans_start = jiffies;
spin_unlock_irqrestore(&card->tx_dma_lock, flags);
return NETDEV_TX_OK;
-
-error:
- card->netdev_stats.tx_dropped++;
- spin_unlock_irqrestore(&card->tx_dma_lock, flags);
- return NETDEV_TX_LOCKED;
}
/**
@@ -1025,9 +1042,10 @@ static irqreturn_t gelic_net_interrupt(i
if (status & GELIC_NET_TXINT) {
spin_lock_irqsave(&card->tx_dma_lock, flags);
card->tx_dma_progress = 0;
+ gelic_net_release_tx_chain(card, 0);
+ /* kick outstanding tx descriptor if any */
+ gelic_net_kick_txdma(card, card->tx_chain.tail);
spin_unlock_irqrestore(&card->tx_dma_lock, flags);
- /* start pending DMA */
- gelic_net_xmit(NULL, netdev);
}
return IRQ_HANDLED;
}
--
Masakazu MOKUNO
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