3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <eduma...@google.com>
commit bc14786a100cc6a81cd060e8031ec481241b418c upstream.
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: Ben Hutchings <b...@decadent.org.uk>
---
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index cbc56f2..8098eea 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -190,7 +190,7 @@ int bnx2x_tx_int(struct bnx2x *bp, struct bnx2x_fp_txdata
*txdata)
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);
@@ -2516,8 +2516,6 @@ int bnx2x_poll(struct napi_struct *napi, int budget)
/* 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,
@@ -3171,7 +3169,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct
net_device *dev)
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
@@ -3180,7 +3178,7 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct
net_device *dev)
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++;
--
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