Commit ea811b79 authored by Brian King's avatar Brian King Committed by David S. Miller

bnx2x: Prevent load reordering in tx completion processing

This patch fixes an issue seen on Power systems with bnx2x which results
in the skb is NULL WARN_ON in bnx2x_free_tx_pkt firing due to the skb
pointer getting loaded in bnx2x_free_tx_pkt prior to the hw_cons
load in bnx2x_tx_int. Adding a read memory barrier resolves the issue.
Signed-off-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0cea0e11
...@@ -285,6 +285,9 @@ int bnx2x_tx_int(struct bnx2x *bp, struct bnx2x_fp_txdata *txdata) ...@@ -285,6 +285,9 @@ int bnx2x_tx_int(struct bnx2x *bp, struct bnx2x_fp_txdata *txdata)
hw_cons = le16_to_cpu(*txdata->tx_cons_sb); hw_cons = le16_to_cpu(*txdata->tx_cons_sb);
sw_cons = txdata->tx_pkt_cons; sw_cons = txdata->tx_pkt_cons;
/* Ensure subsequent loads occur after hw_cons */
smp_rmb();
while (sw_cons != hw_cons) { while (sw_cons != hw_cons) {
u16 pkt_cons; u16 pkt_cons;
......
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