[5/9] ixgbevf: add support for padding packet

Following the logic from commit 2de6aa3a666e
("ixgbe: Add support for padding packet")

Add support for providing a buffer with headroom and tailroom
to allow for shared info, NET_SKB_PAD, and NET_IP_ALIGN.  With this
combined with the DMA changes we can start using build_skb to build frames
around an incoming Rx buffer instead of having to memcpy the headers.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |   11 +++++++
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   32 ++++++++++++++++++---
 2 files changed, 39 insertions(+), 4 deletions(-)

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On Behalf Of
> Emil Tantilov
> Sent: Tuesday, January 30, 2018 4:52 PM
> To: intel-wired-lan@lists.osuosl.org
> Subject: [Intel-wired-lan] [PATCH 5/9] ixgbevf: add support for padding packet
> 
> Following the logic from commit 2de6aa3a666e
> ("ixgbe: Add support for padding packet")
> 
> Add support for providing a buffer with headroom and tailroom
> to allow for shared info, NET_SKB_PAD, and NET_IP_ALIGN.  With this
> combined with the DMA changes we can start using build_skb to build frames
> around an incoming Rx buffer instead of having to memcpy the headers.
> 
> Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |   11 +++++++
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   32
> ++++++++++++++++++---
>  2 files changed, 39 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> index d691d64..fe7111c 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> @@ -90,6 +90,7 @@ struct ixgbevf_rx_queue_stats {
> 
>  enum ixgbevf_ring_state_t {
>  	__IXGBEVF_RX_3K_BUFFER,
> +	__IXGBEVF_RX_BUILD_SKB_ENABLED,
>  	__IXGBEVF_TX_DETECT_HANG,
>  	__IXGBEVF_HANG_CHECK_ARMED,
>  };
> @@ -179,11 +180,21 @@ struct ixgbevf_ring {
>  #define clear_ring_uses_large_buffer(ring) \
>  	clear_bit(__IXGBEVF_RX_3K_BUFFER, &(ring)->state)
> 
> +#define ring_uses_build_skb(ring) \
> +	test_bit(__IXGBEVF_RX_BUILD_SKB_ENABLED, &(ring)->state)
> +#define set_ring_build_skb_enabled(ring) \
> +	set_bit(__IXGBEVF_RX_BUILD_SKB_ENABLED, &(ring)->state)
> +#define clear_ring_build_skb_enabled(ring) \
> +	clear_bit(__IXGBEVF_RX_BUILD_SKB_ENABLED, &(ring)->state)
> +
>  static inline unsigned int ixgbevf_rx_bufsz(struct ixgbevf_ring *ring)
>  {
>  #if (PAGE_SIZE < 8192)
>  	if (ring_uses_large_buffer(ring))
>  		return IXGBEVF_RXBUFFER_3072;
> +
> +	if (ring_uses_build_skb(ring))
> +		return IXGBEVF_MAX_FRAME_BUILD_SKB;
>  #endif
>  	return IXGBEVF_RXBUFFER_2048;
>  }
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> index cb9d00a..d797265 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> @@ -554,6 +554,11 @@ static bool ixgbevf_is_non_eop(struct ixgbevf_ring
> *rx_ring,
>  	return true;
>  }
> 
> +static inline unsigned int ixgbevf_rx_offset(struct ixgbevf_ring *rx_ring)
> +{
> +	return ring_uses_build_skb(rx_ring) ? IXGBEVF_SKB_PAD : 0;
> +}
> +
>  static bool ixgbevf_alloc_mapped_page(struct ixgbevf_ring *rx_ring,
>  				      struct ixgbevf_rx_buffer *bi)
>  {
> @@ -588,7 +593,7 @@ static bool ixgbevf_alloc_mapped_page(struct
> ixgbevf_ring *rx_ring,
> 
>  	bi->dma = dma;
>  	bi->page = page;
> -	bi->page_offset = 0;
> +	bi->page_offset = ixgbevf_rx_offset(rx_ring);
>  	bi->pagecnt_bias = 1;
>  	rx_ring->rx_stats.alloc_rx_page++;
> 
> @@ -803,7 +808,9 @@ static bool ixgbevf_add_rx_frag(struct ixgbevf_ring
> *rx_ring,
>  #if (PAGE_SIZE < 8192)
>  	unsigned int truesize = ixgbevf_rx_pg_size(rx_ring) / 2;
>  #else
> -	unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
> +	unsigned int truesize = ring_uses_build_skb(rx_ring) ?
> +				SKB_DATA_ALIGN(IXGBEVF_SKB_PAD + size) :
> +				SKB_DATA_ALIGN(size);
>  #endif
>  	unsigned int pull_len;
> 
> @@ -1776,8 +1783,19 @@ static void ixgbevf_configure_rx_ring(struct
> ixgbevf_adapter *adapter,
> 
>  	ixgbevf_configure_srrctl(adapter, ring, reg_idx);
> 
> -	/* allow any size packet since we can handle overflow */
> -	rxdctl &= ~IXGBE_RXDCTL_RLPML_EN;
> +	/* RXDCTL.RLPML does not work on 82599 */
> +	if (adapter->hw.mac.type != ixgbe_mac_82599_vf) {
> +		rxdctl &= ~(IXGBE_RXDCTL_RLPMLMASK |
> +			    IXGBE_RXDCTL_RLPML_EN);
> +
> +#if (PAGE_SIZE < 8192)
> +		/* Limit the maximum frame size so we don't overrun the skb
> */
> +		if (ring_uses_build_skb(ring) &&
> +		   !ring_uses_large_buffer(ring))
> +			rxdctl |= IXGBEVF_MAX_FRAME_BUILD_SKB |
> +				  IXGBE_RXDCTL_RLPML_EN;
> +#endif
> +	}
> 
>  	rxdctl |= IXGBE_RXDCTL_ENABLE | IXGBE_RXDCTL_VME;
>  	IXGBE_WRITE_REG(hw, IXGBE_VFRXDCTL(reg_idx), rxdctl);
> @@ -1793,11 +1811,14 @@ static void ixgbevf_set_rx_buffer_len(struct
> ixgbevf_adapter *adapter,
>  	unsigned int max_frame = netdev->mtu + ETH_HLEN + ETH_FCS_LEN;
> 
>  	/* set build_skb and buffer size flags */
> +	clear_ring_build_skb_enabled(rx_ring);
>  	clear_ring_uses_large_buffer(rx_ring);
> 
>  	if (adapter->flags & IXGBEVF_FLAGS_LEGACY_RX)
>  		return;
> 
> +	set_ring_build_skb_enabled(rx_ring);
> +
>  #if (PAGE_SIZE < 8192)
>  	if (max_frame <= IXGBEVF_MAX_FRAME_BUILD_SKB)
>  		return;
> @@ -3890,6 +3911,9 @@ static int ixgbevf_change_mtu(struct net_device
> *netdev, int new_mtu)
>  	/* must set new MTU before calling down or up */
>  	netdev->mtu = new_mtu;
> 
> +	if (netif_running(netdev))
> +		ixgbevf_reinit_locked(adapter);
> +
>  	return 0;
>  }
> 
> 
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> Intel-wired-lan@osuosl.org
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Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>