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Commit 71da6197 authored by Anjali Singhai's avatar Anjali Singhai Committed by Jeff Kirsher
Browse files

i40e: Fix TSO with more than 8 frags per segment issue 



The hardware has some limitations the driver needs to adhere to,
that we found in extended testing.
  1) no more than 8 descriptors per packet on the wire
  2) no header can span more than 3 descriptors

If one of these events occurs, the hardware will generate an internal
error and freeze the Tx queue.

This patch linearizes the skb to avoid these situations.

Change-ID: I37dab7d3966e14895a9663ec4d0aaa8eb0d9e115
Signed-off-by: default avatarAnjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: default avatarJim Young <james.m.young@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent b67a0335

drivers/net/ethernet/intel/i40e/i40e_txrx.c

+65 −0
Original line number Diff line number Diff line
@@ -2139,6 +2139,67 @@ static int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size) 
	return __i40e_maybe_stop_tx(tx_ring, size);

}



/**

 * i40e_chk_linearize - Check if there are more than 8 fragments per packet

 * @skb:      send buffer

 * @tx_flags: collected send information

 * @hdr_len:  size of the packet header

 *

 * Note: Our HW can't scatter-gather more than 8 fragments to build

 * a packet on the wire and so we need to figure out the cases where we

 * need to linearize the skb.

 **/

static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags,

			       const u8 hdr_len)

{

	struct skb_frag_struct *frag;

	bool linearize = false;

	unsigned int size = 0;

	u16 num_frags;

	u16 gso_segs;



	num_frags = skb_shinfo(skb)->nr_frags;

	gso_segs = skb_shinfo(skb)->gso_segs;



	if (tx_flags & (I40E_TX_FLAGS_TSO | I40E_TX_FLAGS_FSO)) {

		u16 j = 1;



		if (num_frags < (I40E_MAX_BUFFER_TXD))

			goto linearize_chk_done;

		/* try the simple math, if we have too many frags per segment */

		if (DIV_ROUND_UP((num_frags + gso_segs), gso_segs) >

		    I40E_MAX_BUFFER_TXD) {

			linearize = true;

			goto linearize_chk_done;

		}

		frag = &skb_shinfo(skb)->frags[0];

		size = hdr_len;

		/* we might still have more fragments per segment */

		do {

			size += skb_frag_size(frag);

			frag++; j++;

			if (j == I40E_MAX_BUFFER_TXD) {

				if (size < skb_shinfo(skb)->gso_size) {

					linearize = true;

					break;

				}

				j = 1;

				size -= skb_shinfo(skb)->gso_size;

				if (size)

					j++;

				size += hdr_len;

			}

			num_frags--;

		} while (num_frags);

	} else {

		if (num_frags >= I40E_MAX_BUFFER_TXD)

			linearize = true;

	}



linearize_chk_done:

	return linearize;

}



/**

 * i40e_tx_map - Build the Tx descriptor

 * @tx_ring:  ring to send buffer on
@@ -2396,6 +2457,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb, 
	if (tsyn)

		tx_flags |= I40E_TX_FLAGS_TSYN;



	if (i40e_chk_linearize(skb, tx_flags, hdr_len))

		if (skb_linearize(skb))

			goto out_drop;



	skb_tx_timestamp(skb);



	/* always enable CRC insertion offload */

drivers/net/ethernet/intel/i40e/i40e_txrx.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t { 


#define i40e_rx_desc i40e_32byte_rx_desc



#define I40E_MAX_BUFFER_TXD	8

#define I40E_MIN_TX_LEN		17

#define I40E_MAX_DATA_PER_TXD	8192

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

+65 −0
Original line number Diff line number Diff line
@@ -1380,6 +1380,67 @@ 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_chk_linearize - Check if there are more than 8 fragments per packet

 * @skb:      send buffer

 * @tx_flags: collected send information

 * @hdr_len:  size of the packet header

 *

 * Note: Our HW can't scatter-gather more than 8 fragments to build

 * a packet on the wire and so we need to figure out the cases where we

 * need to linearize the skb.

 **/

static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags,

			       const u8 hdr_len)

{

	struct skb_frag_struct *frag;

	bool linearize = false;

	unsigned int size = 0;

	u16 num_frags;

	u16 gso_segs;



	num_frags = skb_shinfo(skb)->nr_frags;

	gso_segs = skb_shinfo(skb)->gso_segs;



	if (tx_flags & (I40E_TX_FLAGS_TSO | I40E_TX_FLAGS_FSO)) {

		u16 j = 1;



		if (num_frags < (I40E_MAX_BUFFER_TXD))

			goto linearize_chk_done;

		/* try the simple math, if we have too many frags per segment */

		if (DIV_ROUND_UP((num_frags + gso_segs), gso_segs) >

		    I40E_MAX_BUFFER_TXD) {

			linearize = true;

			goto linearize_chk_done;

		}

		frag = &skb_shinfo(skb)->frags[0];

		size = hdr_len;

		/* we might still have more fragments per segment */

		do {

			size += skb_frag_size(frag);

			frag++; j++;

			if (j == I40E_MAX_BUFFER_TXD) {

				if (size < skb_shinfo(skb)->gso_size) {

					linearize = true;

					break;

				}

				j = 1;

				size -= skb_shinfo(skb)->gso_size;

				if (size)

					j++;

				size += hdr_len;

			}

			num_frags--;

		} while (num_frags);

	} else {

		if (num_frags >= I40E_MAX_BUFFER_TXD)

			linearize = true;

	}



linearize_chk_done:

	return linearize;

}



/**

 * i40e_tx_map - Build the Tx descriptor

 * @tx_ring:  ring to send buffer on
@@ -1654,6 +1715,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb, 
	else if (tso)

		tx_flags |= I40E_TX_FLAGS_TSO;



	if (i40e_chk_linearize(skb, tx_flags, hdr_len))

		if (skb_linearize(skb))

			goto out_drop;



	skb_tx_timestamp(skb);



	/* always enable CRC insertion offload */

drivers/net/ethernet/intel/i40evf/i40e_txrx.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t { 


#define i40e_rx_desc i40e_32byte_rx_desc



#define I40E_MAX_BUFFER_TXD	8

#define I40E_MIN_TX_LEN		17

#define I40E_MAX_DATA_PER_TXD	8192