From: Greg KH <gre...@linuxfoundation.org> 3.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <eduma...@google.com> [ Upstream commit bc14786a100cc6a81cd060e8031ec481241b418c ] There is a off by one error in the minimal number of BD in bnx2x_start_xmit() and bnx2x_tx_int() before stopping/resuming tx queue. A full size GSO packet, with data included in skb->head really needs (MAX_SKB_FRAGS + 4) BDs, because of bnx2x_tx_split() This error triggers if BQL is disabled and heavy TCP transmit traffic occurs. bnx2x_tx_split() definitely can be called, remove a wrong comment. Reported-by: Tomas Hruby <thr...@google.com> Signed-off-by: Eric Dumazet <eduma...@google.com> Cc: Eilon Greenstein <eil...@broadcom.com> Cc: Yaniv Rosner <yan...@broadcom.com> Cc: Merav Sicron <mer...@broadcom.com> Cc: Tom Herbert <therb...@google.com> Cc: Robert Evans <eva...@google.com> Cc: Willem de Bruijn <will...@google.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c @@ -191,7 +191,7 @@ int bnx2x_tx_int(struct bnx2x *bp, struc if ((netif_tx_queue_stopped(txq)) && (bp->state == BNX2X_STATE_OPEN) && - (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 3)) + (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 4)) netif_tx_wake_queue(txq); __netif_tx_unlock(txq); @@ -2349,8 +2349,6 @@ int bnx2x_poll(struct napi_struct *napi, /* we split the first BD into headers and data BDs * to ease the pain of our fellow microcode engineers * we use one mapping for both BDs - * So far this has only been observed to happen - * in Other Operating Systems(TM) */ static noinline u16 bnx2x_tx_split(struct bnx2x *bp, struct bnx2x_fp_txdata *txdata, @@ -3002,7 +3000,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_b txdata->tx_bd_prod += nbd; - if (unlikely(bnx2x_tx_avail(bp, txdata) < MAX_SKB_FRAGS + 3)) { + if (unlikely(bnx2x_tx_avail(bp, txdata) < MAX_SKB_FRAGS + 4)) { netif_tx_stop_queue(txq); /* paired memory barrier is in bnx2x_tx_int(), we have to keep @@ -3011,7 +3009,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_b smp_mb(); fp->eth_q_stats.driver_xoff++; - if (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 3) + if (bnx2x_tx_avail(bp, txdata) >= MAX_SKB_FRAGS + 4) netif_tx_wake_queue(txq); } txdata->tx_pkt++; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/