[PATCH net-next 3/4] sfc: only use fixed-id if the skb asks for it

[Edward Cree]

AIUI, the NETIF_F_TSO_MANGLEID flag is a signal to the stack that a
 driver may _need_ to mangle IDs in order to do TSO, and conversely
 a signal from the stack that the driver is permitted to do so.
Since we support both fixed and incrementing IPIDs, we should rely
 on the SKB_GSO_FIXEDID flag on a per-skb basis, rather than using
 the MANGLEID feature to make all TSOs fixed-id.
Includes other minor cleanups of ef100_make_tso_desc() coding style.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/ef100_nic.c |  2 +-
 drivers/net/ethernet/sfc/ef100_tx.c  | 13 +++++++------
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef100_nic.c 
b/drivers/net/ethernet/sfc/ef100_nic.c
index bf92cdc60cda..8a187a16ac89 100644
--- a/drivers/net/ethernet/sfc/ef100_nic.c
+++ b/drivers/net/ethernet/sfc/ef100_nic.c
@@ -694,7 +694,7 @@ static unsigned int ef100_check_caps(const struct efx_nic 
*efx,
 #define EF100_OFFLOAD_FEATURES (NETIF_F_HW_CSUM | NETIF_F_RXCSUM |     \
        NETIF_F_HIGHDMA | NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_NTUPLE | \
        NETIF_F_RXHASH | NETIF_F_RXFCS | NETIF_F_TSO_ECN | NETIF_F_RXALL | \
-       NETIF_F_TSO_MANGLEID | NETIF_F_HW_VLAN_CTAG_TX)
+       NETIF_F_HW_VLAN_CTAG_TX)
 
 const struct efx_nic_type ef100_pf_nic_type = {
        .revision = EFX_REV_EF100,
diff --git a/drivers/net/ethernet/sfc/ef100_tx.c 
b/drivers/net/ethernet/sfc/ef100_tx.c
index d267b12bdaa0..ad0ad9bad423 100644
--- a/drivers/net/ethernet/sfc/ef100_tx.c
+++ b/drivers/net/ethernet/sfc/ef100_tx.c
@@ -187,21 +187,22 @@ static void ef100_make_tso_desc(struct efx_nic *efx,
                                struct efx_tx_buffer *buffer, efx_oword_t *txd,
                                unsigned int segment_count)
 {
-       u32 mangleid = (efx->net_dev->features & NETIF_F_TSO_MANGLEID) ||
-               skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID ?
-               ESE_GZ_TX_DESC_IP4_ID_NO_OP :
-               ESE_GZ_TX_DESC_IP4_ID_INC_MOD16;
-       u16 vlan_enable =  efx->net_dev->features & NETIF_F_HW_VLAN_CTAG_TX ?
-               skb_vlan_tag_present(skb) : 0;
        bool gso_partial = skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL;
        unsigned int len, ip_offset, tcp_offset, payload_segs;
+       u32 mangleid = ESE_GZ_TX_DESC_IP4_ID_INC_MOD16;
        unsigned int outer_ip_offset, outer_l4_offset;
        u16 vlan_tci = skb_vlan_tag_get(skb);
        u32 mss = skb_shinfo(skb)->gso_size;
        bool encap = skb->encapsulation;
+       u16 vlan_enable = 0;
        struct tcphdr *tcp;
        u32 paylen;
 
+       if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID)
+               mangleid = ESE_GZ_TX_DESC_IP4_ID_NO_OP;
+       if (efx->net_dev->features & NETIF_F_HW_VLAN_CTAG_TX)
+               vlan_enable = skb_vlan_tag_present(skb);
+
        len = skb->len - buffer->len;
        /* We use 1 for the TSO descriptor and 1 for the header */
        payload_segs = segment_count - 2;