> I'm not sure "correct the statistics" is the best way to describe this
> change. Maybe "keep track of correct TXBD count in
> enetc_map_tx_tso_buffs()"?
Hi Vladimir,
Inspired by Michal, I think we don't need to keep the count variable, because
we already have index "i", we just need to record the value of the initial i at the
beginning. So I plan to do this optimization on the net-next tree in the future.
So I don't think it is necessary to modify enetc_map_tx_tso_hdr().
> The bug is that not all TX buffers are freed on error, not that some
> statistics are wrong.
>
> > drivers/net/ethernet/freescale/enetc/enetc.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c
> b/drivers/net/ethernet/freescale/enetc/enetc.c
> > index 01c09fd26f9f..0658c06a23c1 100644
> > --- a/drivers/net/ethernet/freescale/enetc/enetc.c
> > +++ b/drivers/net/ethernet/freescale/enetc/enetc.c
> > @@ -759,6 +759,7 @@ static int enetc_lso_hw_offload(struct enetc_bdr
> *tx_ring, struct sk_buff *skb)
> > static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff
> *skb)
> > {
> > struct enetc_ndev_priv *priv = netdev_priv(tx_ring->ndev);
> > + bool ext_bd = skb_vlan_tag_present(skb);
> > int hdr_len, total_len, data_len;
> > struct enetc_tx_swbd *tx_swbd;
> > union enetc_tx_bd *txbd;
> > @@ -792,7 +793,7 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr
> *tx_ring, struct sk_buff *skb
> > csum = enetc_tso_hdr_csum(&tso, skb, hdr, hdr_len, &pos);
> > enetc_map_tx_tso_hdr(tx_ring, skb, tx_swbd, txbd, &i, hdr_len,
> data_len);
> > bd_data_num = 0;
> > - count++;
> > + count += ext_bd ? 2 : 1;
> >
> > while (data_len > 0) {
> > int size;
> > --
> > 2.34.1
> >
>
> stylistic nitpick: I think this implementation choice obscures the fact,
> to an unfamiliar reader, that the requirement for an extended TXBD comes
> from enetc_map_tx_tso_hdr(). This is because you repeat the condition
> for skb_vlan_tag_present(), but it's not obvious it's correlated to the
> other one. Something like the change below is more expressive in this
> regard, in my opinion:
>
> diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c
> b/drivers/net/ethernet/freescale/enetc/enetc.c
> index fe3967268a19..6178157611db 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc.c
> @@ -410,14 +410,15 @@ static int enetc_map_tx_buffs(struct enetc_bdr
> *tx_ring, struct sk_buff *skb)
> return 0;
> }
>
> -static void enetc_map_tx_tso_hdr(struct enetc_bdr *tx_ring, struct sk_buff
> *skb,
> - struct enetc_tx_swbd *tx_swbd,
> - union enetc_tx_bd *txbd, int *i, int hdr_len,
> - int data_len)
> +static int enetc_map_tx_tso_hdr(struct enetc_bdr *tx_ring, struct sk_buff
> *skb,
> + struct enetc_tx_swbd *tx_swbd,
> + union enetc_tx_bd *txbd, int *i, int hdr_len,
> + int data_len)
> {
> union enetc_tx_bd txbd_tmp;
> u8 flags = 0, e_flags = 0;
> dma_addr_t addr;
> + int count = 1;
>
> enetc_clear_tx_bd(&txbd_tmp);
> addr = tx_ring->tso_headers_dma + *i * TSO_HEADER_SIZE;
> @@ -460,7 +461,10 @@ static void enetc_map_tx_tso_hdr(struct enetc_bdr
> *tx_ring, struct sk_buff *skb,
> /* Write the BD */
> txbd_tmp.ext.e_flags = e_flags;
> *txbd = txbd_tmp;
> + count++;
> }
> +
> + return count;
> }
>
> static int enetc_map_tx_tso_data(struct enetc_bdr *tx_ring, struct sk_buff
> *skb,
> @@ -786,7 +790,6 @@ static int enetc_lso_hw_offload(struct enetc_bdr
> *tx_ring, struct sk_buff *skb)
> static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff
> *skb)
> {
> struct enetc_ndev_priv *priv = netdev_priv(tx_ring->ndev);
> - bool ext_bd = skb_vlan_tag_present(skb);
> int hdr_len, total_len, data_len;
> struct enetc_tx_swbd *tx_swbd;
> union enetc_tx_bd *txbd;
> @@ -818,9 +821,9 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr
> *tx_ring, struct sk_buff *skb
>
> /* compute the csum over the L4 header */
> csum = enetc_tso_hdr_csum(&tso, skb, hdr, hdr_len, &pos);
> - enetc_map_tx_tso_hdr(tx_ring, skb, tx_swbd, txbd, &i, hdr_len,
> data_len);
> + count += enetc_map_tx_tso_hdr(tx_ring, skb, tx_swbd, txbd, &i,
> + hdr_len, data_len);
> bd_data_num = 0;
> - count += ext_bd ? 2 : 1;
>
> while (data_len > 0) {
> int size;
