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

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
...@@ -2139,6 +2139,67 @@ static int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size) ...@@ -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); 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 * i40e_tx_map - Build the Tx descriptor
* @tx_ring: ring to send buffer on * @tx_ring: ring to send buffer on
...@@ -2396,6 +2457,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb, ...@@ -2396,6 +2457,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
if (tsyn) if (tsyn)
tx_flags |= I40E_TX_FLAGS_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); skb_tx_timestamp(skb);
/* always enable CRC insertion offload */ /* always enable CRC insertion offload */
......
...@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t { ...@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t {
#define i40e_rx_desc i40e_32byte_rx_desc #define i40e_rx_desc i40e_32byte_rx_desc
#define I40E_MAX_BUFFER_TXD 8
#define I40E_MIN_TX_LEN 17 #define I40E_MIN_TX_LEN 17
#define I40E_MAX_DATA_PER_TXD 8192 #define I40E_MAX_DATA_PER_TXD 8192
......
...@@ -1380,6 +1380,67 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring, ...@@ -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); 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 * i40e_tx_map - Build the Tx descriptor
* @tx_ring: ring to send buffer on * @tx_ring: ring to send buffer on
...@@ -1654,6 +1715,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb, ...@@ -1654,6 +1715,10 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
else if (tso) else if (tso)
tx_flags |= I40E_TX_FLAGS_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); skb_tx_timestamp(skb);
/* always enable CRC insertion offload */ /* always enable CRC insertion offload */
......
...@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t { ...@@ -112,6 +112,7 @@ enum i40e_dyn_idx_t {
#define i40e_rx_desc i40e_32byte_rx_desc #define i40e_rx_desc i40e_32byte_rx_desc
#define I40E_MAX_BUFFER_TXD 8
#define I40E_MIN_TX_LEN 17 #define I40E_MIN_TX_LEN 17
#define I40E_MAX_DATA_PER_TXD 8192 #define I40E_MAX_DATA_PER_TXD 8192
......
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