On Wed, Feb 19, 2025 at 01:42:40PM +0800, Wei Fang wrote:
When creating a TSO header, if the skb is VLAN tagged, the extended BD will be used and the 'count' should be increased by 2 instead of 1. Otherwise, when an error occurs, less tx_swbd will be freed than the actual number.
Fixes: fb8629e2cbfc ("net: enetc: add support for software TSO") Cc: stable@vger.kernel.org Signed-off-by: Wei Fang wei.fang@nxp.com Reviewed-by: Michal Swiatkowski michal.swiatkowski@linux.intel.com
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()"? 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;