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Commit 30520831 authored by Anjali Singhai Jain's avatar Anjali Singhai Jain Committed by Jeff Kirsher
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i40e/i40evf: Fix mixed size frags and linearization 



This patch fixes a bug where the i40e Tx queue will hang if this
skb is passed to the driver.

With mixed size fragments while using TSO there was a corner case
where we needed to linearize but we were not. This was seen with
iSCSI traffic and could be reproduced with a frag list that looks
like this:

num_frags = 17, gso_segs = 17, hdr_len = 66,
skb_shinfo(skb)->gso_size = 1448
size = 3002, j = 1, frag_size = 2936, num_frags = 17
size = 4268, j = 1, frag_size = 4096, num_frags = 16
size = 5534, j = 1, frag_size = 4096, num_frags = 15
size = 5352, j = 1, frag_size = 4096, num_frags = 14
size = 5170, j = 1, frag_size = 4096, num_frags = 13
size = 3468, j = 1, frag_size = 2576, num_frags = 12
size = 750, j = 1, frag_size = 112, num_frags = 11
size = 862, j = 2, frag_size = 112, num_frags = 10
size = 974, j = 3, frag_size = 112, num_frags = 9
size = 1126, j = 4, frag_size = 152, num_frags = 8
size = 1330, j = 5, frag_size = 204, num_frags = 7
size = 1534, j = 6, frag_size = 204, num_frags = 6
size = 356, j = 1, frag_size = 204, num_frags = 5
size = 560, j = 2, frag_size = 204, num_frags = 4
size = 764, j = 3, frag_size = 204, num_frags = 3
size = 968, j = 4, frag_size = 204, num_frags = 2
size = 1140, j = 5, frag_size = 172, num_frags = 1
result: linearize = 0, j = 6

Change-ID: I79bb1aeab0af255fe2ce28e93672a85d85bf47e8
Signed-off-by: default avatarAnjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: default avatarJesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 6e540309

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

+10 −15
Original line number Diff line number Diff line
@@ -2410,14 +2410,12 @@ static int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int 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)

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

{

	struct skb_frag_struct *frag;

	bool linearize = false;
@@ -2429,7 +2427,7 @@ static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags, 
	gso_segs = skb_shinfo(skb)->gso_segs;



	if (tx_flags & (I40E_TX_FLAGS_TSO | I40E_TX_FLAGS_FSO)) {

		u16 j = 1;

		u16 j = 0;



		if (num_frags < (I40E_MAX_BUFFER_TXD))

			goto linearize_chk_done;
@@ -2440,22 +2438,19 @@ static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags, 
			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 ((size >= skb_shinfo(skb)->gso_size) &&

			    (j < I40E_MAX_BUFFER_TXD)) {

				size = (size % skb_shinfo(skb)->gso_size);

				j = (size) ? 1 : 0;

			}

			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 {
@@ -2724,7 +2719,7 @@ 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 (i40e_chk_linearize(skb, tx_flags))

		if (skb_linearize(skb))

			goto out_drop;

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

+10 −15
Original line number Diff line number Diff line
@@ -1619,14 +1619,12 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring, 
 * 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)

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

{

	struct skb_frag_struct *frag;

	bool linearize = false;
@@ -1638,7 +1636,7 @@ static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags, 
	gso_segs = skb_shinfo(skb)->gso_segs;



	if (tx_flags & (I40E_TX_FLAGS_TSO | I40E_TX_FLAGS_FSO)) {

		u16 j = 1;

		u16 j = 0;



		if (num_frags < (I40E_MAX_BUFFER_TXD))

			goto linearize_chk_done;
@@ -1649,22 +1647,19 @@ static bool i40e_chk_linearize(struct sk_buff *skb, u32 tx_flags, 
			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 ((size >= skb_shinfo(skb)->gso_size) &&

			    (j < I40E_MAX_BUFFER_TXD)) {

				size = (size % skb_shinfo(skb)->gso_size);

				j = (size) ? 1 : 0;

			}

			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 {
@@ -1950,7 +1945,7 @@ 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 (i40e_chk_linearize(skb, tx_flags))

		if (skb_linearize(skb))

			goto out_drop;