[PATCH v2] ucc_geth: Reduce IRQ off in xmit path
From: Joakim Tjernlund <hidden>
Date: 2012-09-20 08:17:11
Subsystem:
freescale quicc engine ucc ethernet driver, networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Currently ucc_geth_start_xmit wraps IRQ off for the
whole body just to be safe.
Reduce the IRQ off period to a minimum.
Signed-off-by: Joakim Tjernlund <redacted>
---
v2: Move assignment of ugeth->tx_skbuff[txQ][ugeth->skb_curtx[txQ]]
inside IRQ off section to prevent racing against
ucc_geth_tx(). Spotted by Francois Romieu [off-list ref]
drivers/net/ethernet/freescale/ucc_geth.c | 11 +++++------
1 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/freescale/ucc_geth.c b/drivers/net/ethernet/freescale/ucc_geth.c
index 9ac14f8..0100bca 100644
--- a/drivers/net/ethernet/freescale/ucc_geth.c
+++ b/drivers/net/ethernet/freescale/ucc_geth.c@@ -3181,21 +3181,20 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) ugeth_vdbg("%s: IN", __func__); - spin_lock_irqsave(&ugeth->lock, flags); - dev->stats.tx_bytes += skb->len; /* Start from the next BD that should be filled */ bd = ugeth->txBd[txQ]; bd_status = in_be32((u32 __iomem *)bd); - /* Save the skb pointer so we can free it later */ - ugeth->tx_skbuff[txQ][ugeth->skb_curtx[txQ]] = skb; /* Update the current skb pointer (wrapping if this was the last) */ ugeth->skb_curtx[txQ] = (ugeth->skb_curtx[txQ] + 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]); + spin_lock_irqsave(&ugeth->lock, flags); + /* Save the skb pointer so we can free it later */ + ugeth->tx_skbuff[txQ][ugeth->skb_curtx[txQ]] = skb; /* set up the buffer descriptor */ out_be32(&((struct qe_bd __iomem *)bd)->buf, dma_map_single(ugeth->dev, skb->data,
@@ -3207,6 +3206,8 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) /* set bd status and length */ out_be32((u32 __iomem *)bd, bd_status); + spin_unlock_irqrestore(&ugeth->lock, flags); + /* Move to next BD in the ring */ if (!(bd_status & T_W))
@@ -3238,8 +3239,6 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) uccf = ugeth->uccf; out_be16(uccf->p_utodr, UCC_FAST_TOD); #endif - spin_unlock_irqrestore(&ugeth->lock, flags); - return NETDEV_TX_OK; }
--
1.7.8.6