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ixgbe: Add support for padding packet
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This patch adds 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: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Alexander Duyck authored and Jeff Kirsher committed Feb 16, 2017
1 parent 3fd2187 commit 2de6aa3
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Showing 2 changed files with 56 additions and 4 deletions.
17 changes: 17 additions & 0 deletions drivers/net/ethernet/intel/ixgbe/ixgbe.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,14 @@
#define IXGBE_RXBUFFER_4K 4096
#define IXGBE_MAX_RXBUFFER 16384 /* largest size for a single descriptor */

#define IXGBE_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
#if (PAGE_SIZE < 8192)
#define IXGBE_MAX_FRAME_BUILD_SKB \
(SKB_WITH_OVERHEAD(IXGBE_RXBUFFER_2K) - IXGBE_SKB_PAD)
#else
#define IGB_MAX_FRAME_BUILD_SKB IXGBE_RXBUFFER_2K
#endif

/*
* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
* reserve 64 more, and skb_shared_info adds an additional 320 bytes more,
Expand Down Expand Up @@ -227,6 +235,7 @@ struct ixgbe_rx_queue_stats {

enum ixgbe_ring_state_t {
__IXGBE_RX_3K_BUFFER,
__IXGBE_RX_BUILD_SKB_ENABLED,
__IXGBE_RX_RSC_ENABLED,
__IXGBE_RX_CSUM_UDP_ZERO_ERR,
__IXGBE_RX_FCOE,
Expand All @@ -236,6 +245,9 @@ enum ixgbe_ring_state_t {
__IXGBE_HANG_CHECK_ARMED,
};

#define ring_uses_build_skb(ring) \
test_bit(__IXGBE_RX_BUILD_SKB_ENABLED, &(ring)->state)

struct ixgbe_fwd_adapter {
unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];
struct net_device *netdev;
Expand Down Expand Up @@ -347,6 +359,10 @@ static inline unsigned int ixgbe_rx_bufsz(struct ixgbe_ring *ring)
{
if (test_bit(__IXGBE_RX_3K_BUFFER, &ring->state))
return IXGBE_RXBUFFER_3K;
#if (PAGE_SIZE < 8192)
if (ring_uses_build_skb(ring))
return IXGBE_MAX_FRAME_BUILD_SKB;
#endif
return IXGBE_RXBUFFER_2K;
}

Expand Down Expand Up @@ -545,6 +561,7 @@ struct ixgbe_adapter {
#define IXGBE_FLAG2_VLAN_PROMISC BIT(13)
#define IXGBE_FLAG2_EEE_CAPABLE BIT(14)
#define IXGBE_FLAG2_EEE_ENABLED BIT(15)
#define IXGBE_FLAG2_RX_LEGACY BIT(16)

/* Tx fast path data */
int num_tx_queues;
Expand Down
43 changes: 39 additions & 4 deletions drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1552,6 +1552,11 @@ static inline void ixgbe_rx_checksum(struct ixgbe_ring *ring,
}
}

static inline unsigned int ixgbe_rx_offset(struct ixgbe_ring *rx_ring)
{
return ring_uses_build_skb(rx_ring) ? IXGBE_SKB_PAD : 0;
}

static bool ixgbe_alloc_mapped_page(struct ixgbe_ring *rx_ring,
struct ixgbe_rx_buffer *bi)
{
Expand Down Expand Up @@ -1588,7 +1593,7 @@ static bool ixgbe_alloc_mapped_page(struct ixgbe_ring *rx_ring,

bi->dma = dma;
bi->page = page;
bi->page_offset = 0;
bi->page_offset = ixgbe_rx_offset(rx_ring);
bi->pagecnt_bias = 1;

return true;
Expand Down Expand Up @@ -2001,7 +2006,9 @@ static void ixgbe_add_rx_frag(struct ixgbe_ring *rx_ring,
#if (PAGE_SIZE < 8192)
unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(size);
unsigned int truesize = ring_uses_build_skb(rx_ring) ?
SKB_DATA_ALIGN(IXGBE_SKB_PAD + size) :
SKB_DATA_ALIGN(size);
#endif
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
rx_buffer->page_offset, size, truesize);
Expand Down Expand Up @@ -2083,7 +2090,7 @@ static struct sk_buff *ixgbe_construct_skb(struct ixgbe_ring *rx_ring,
#if (PAGE_SIZE < 8192)
unsigned int truesize = ixgbe_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
unsigned int truesize = SKB_DATA_ALIGN(size);
#endif
struct sk_buff *skb;

Expand Down Expand Up @@ -3410,7 +3417,10 @@ static void ixgbe_configure_srrctl(struct ixgbe_adapter *adapter,
srrctl = IXGBE_RX_HDR_SIZE << IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT;

/* configure the packet buffer length */
srrctl |= ixgbe_rx_bufsz(rx_ring) >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
if (test_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state))
srrctl |= IXGBE_RXBUFFER_3K >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;
else
srrctl |= IXGBE_RXBUFFER_2K >> IXGBE_SRRCTL_BSIZEPKT_SHIFT;

/* configure descriptor type */
srrctl |= IXGBE_SRRCTL_DESCTYPE_ADV_ONEBUF;
Expand Down Expand Up @@ -3744,6 +3754,17 @@ void ixgbe_configure_rx_ring(struct ixgbe_adapter *adapter,
*/
rxdctl &= ~0x3FFFFF;
rxdctl |= 0x080420;
#if (PAGE_SIZE < 8192)
} else {
rxdctl &= ~(IXGBE_RXDCTL_RLPMLMASK |
IXGBE_RXDCTL_RLPML_EN);

/* Limit the maximum frame size so we don't overrun the skb */
if (ring_uses_build_skb(ring) &&
!test_bit(__IXGBE_RX_3K_BUFFER, &ring->state))
rxdctl |= IXGBE_MAX_FRAME_BUILD_SKB |
IXGBE_RXDCTL_RLPML_EN;
#endif
}

/* initialize Rx descriptor 0 */
Expand Down Expand Up @@ -3889,12 +3910,26 @@ static void ixgbe_set_rx_buffer_len(struct ixgbe_adapter *adapter)

clear_ring_rsc_enabled(rx_ring);
clear_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state);
clear_bit(__IXGBE_RX_BUILD_SKB_ENABLED, &rx_ring->state);

if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED)
set_ring_rsc_enabled(rx_ring);

if (test_bit(__IXGBE_RX_FCOE, &rx_ring->state))
set_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state);

if (adapter->flags2 & IXGBE_FLAG2_RX_LEGACY)
continue;

set_bit(__IXGBE_RX_BUILD_SKB_ENABLED, &rx_ring->state);

#if (PAGE_SIZE < 8192)
if (adapter->flags2 & IXGBE_FLAG2_RSC_ENABLED)
set_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state);

if (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN))
set_bit(__IXGBE_RX_3K_BUFFER, &rx_ring->state);
#endif
}
}

Expand Down

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