diff options
Diffstat (limited to 'drivers/net/ethernet/intel/i40evf/i40e_txrx.c')
| -rw-r--r-- | drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 49 |
1 files changed, 24 insertions, 25 deletions
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index ebcc25c05796..cea97daa844c 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -1796,35 +1796,34 @@ static void i40e_create_tx_ctx(struct i40e_ring *tx_ring, } /** - * __i40evf_chk_linearize - Check if there are more than 8 fragments per packet + * __i40evf_chk_linearize - Check if there are more than 8 buffers per packet * @skb: send buffer * - * 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. + * Note: Our HW can't DMA more than 8 buffers to build a packet on the wire + * and so we need to figure out the cases where we need to linearize the skb. + * + * For TSO we need to count the TSO header and segment payload separately. + * As such we need to check cases where we have 7 fragments or more as we + * can potentially require 9 DMA transactions, 1 for the TSO header, 1 for + * the segment payload in the first descriptor, and another 7 for the + * fragments. **/ bool __i40evf_chk_linearize(struct sk_buff *skb) { const struct skb_frag_struct *frag, *stale; - int gso_size, nr_frags, sum; - - /* check to see if TSO is enabled, if so we may get a repreive */ - gso_size = skb_shinfo(skb)->gso_size; - if (unlikely(!gso_size)) - return true; + int nr_frags, sum; - /* no need to check if number of frags is less than 8 */ + /* no need to check if number of frags is less than 7 */ nr_frags = skb_shinfo(skb)->nr_frags; - if (nr_frags < I40E_MAX_BUFFER_TXD) + if (nr_frags < (I40E_MAX_BUFFER_TXD - 1)) return false; /* We need to walk through the list and validate that each group * of 6 fragments totals at least gso_size. However we don't need - * to perform such validation on the first or last 6 since the first - * 6 cannot inherit any data from a descriptor before them, and the - * last 6 cannot inherit any data from a descriptor after them. + * to perform such validation on the last 6 since the last 6 cannot + * inherit any data from a descriptor after them. */ - nr_frags -= I40E_MAX_BUFFER_TXD - 1; + nr_frags -= I40E_MAX_BUFFER_TXD - 2; frag = &skb_shinfo(skb)->frags[0]; /* Initialize size to the negative value of gso_size minus 1. We @@ -1833,21 +1832,21 @@ bool __i40evf_chk_linearize(struct sk_buff *skb) * descriptors for a single transmit as the header and previous * fragment are already consuming 2 descriptors. */ - sum = 1 - gso_size; + sum = 1 - skb_shinfo(skb)->gso_size; - /* Add size of frags 1 through 5 to create our initial sum */ - sum += skb_frag_size(++frag); - sum += skb_frag_size(++frag); - sum += skb_frag_size(++frag); - sum += skb_frag_size(++frag); - sum += skb_frag_size(++frag); + /* Add size of frags 0 through 4 to create our initial sum */ + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); /* Walk through fragments adding latest fragment, testing it, and * then removing stale fragments from the sum. */ stale = &skb_shinfo(skb)->frags[0]; for (;;) { - sum += skb_frag_size(++frag); + sum += skb_frag_size(frag++); /* if sum is negative we failed to make sufficient progress */ if (sum < 0) @@ -1857,7 +1856,7 @@ bool __i40evf_chk_linearize(struct sk_buff *skb) if (!--nr_frags) break; - sum -= skb_frag_size(++stale); + sum -= skb_frag_size(stale++); } return false; |