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i40e: skb->xmit_more support

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Support skb->xmit_more in i40e is straightforward : we need to move
around i40e_maybe_stop_tx() call to correctly test netif_xmit_stopped()
before taking the decision to not kick the NIC.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2014-10-07 13:30:23 -07:00 committed by David S. Miller
parent 44783d8751
commit 4567dc1093
1 changed files with 46 additions and 44 deletions
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90
drivers/net/ethernet/intel/i40e/i40e_txrx.c
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@ -2052,6 +2052,47 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring,
context_desc->type_cmd_tso_mss = cpu_to_le64(cd_type_cmd_tso_mss);
}
/**
* __i40e_maybe_stop_tx - 2nd level check for tx stop conditions
* @tx_ring: the ring to be checked
* @size: the size buffer we want to assure is available
*
* Returns -EBUSY if a stop is needed, else 0
**/
static inline int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
{
netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
/* Memory barrier before checking head and tail */
smp_mb();
/* Check again in a case another CPU has just made room available. */
if (likely(I40E_DESC_UNUSED(tx_ring) < size))
return -EBUSY;
/* A reprieve! - use start_queue because it doesn't call schedule */
netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
++tx_ring->tx_stats.restart_queue;
return 0;
}
/**
* i40e_maybe_stop_tx - 1st level check for tx stop conditions
* @tx_ring: the ring to be checked
* @size: the size buffer we want to assure is available
*
* Returns 0 if stop is not needed
**/
#ifdef I40E_FCOE
int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
#else
static int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
#endif
{
if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
return 0;
return __i40e_maybe_stop_tx(tx_ring, size);
}
/**
* i40e_tx_map - Build the Tx descriptor
* @tx_ring: ring to send buffer on
@ -2195,8 +2236,12 @@ static void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
tx_ring->next_to_use = i;
i40e_maybe_stop_tx(tx_ring, DESC_NEEDED);
/* notify HW of packet */
writel(i, tx_ring->tail);
if (!skb->xmit_more ||
netif_xmit_stopped(netdev_get_tx_queue(tx_ring->netdev,
tx_ring->queue_index)))
writel(i, tx_ring->tail);
return;
@ -2217,47 +2262,6 @@ dma_error:
tx_ring->next_to_use = i;
}
/**
* __i40e_maybe_stop_tx - 2nd level check for tx stop conditions
* @tx_ring: the ring to be checked
* @size: the size buffer we want to assure is available
*
* Returns -EBUSY if a stop is needed, else 0
**/
static inline int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
{
netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index);
/* Memory barrier before checking head and tail */
smp_mb();
/* Check again in a case another CPU has just made room available. */
if (likely(I40E_DESC_UNUSED(tx_ring) < size))
return -EBUSY;
/* A reprieve! - use start_queue because it doesn't call schedule */
netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index);
++tx_ring->tx_stats.restart_queue;
return 0;
}
/**
* i40e_maybe_stop_tx - 1st level check for tx stop conditions
* @tx_ring: the ring to be checked
* @size: the size buffer we want to assure is available
*
* Returns 0 if stop is not needed
**/
#ifdef I40E_FCOE
int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
#else
static int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
#endif
{
if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
return 0;
return __i40e_maybe_stop_tx(tx_ring, size);
}
/**
* i40e_xmit_descriptor_count - calculate number of tx descriptors needed
* @skb: send buffer
@ -2372,8 +2376,6 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
i40e_tx_map(tx_ring, skb, first, tx_flags, hdr_len,
td_cmd, td_offset);
i40e_maybe_stop_tx(tx_ring, DESC_NEEDED);
return NETDEV_TX_OK;
out_drop: