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c4bc44c65b
When we transmit a fragmented skb, we may run into a race like the
following scenario (assume txq->cur_tx is next to txq->dirty_tx):
cpu 0 cpu 1
fec_enet_txq_submit_skb
reserve a bdp for the first fragment
fec_enet_txq_submit_frag_skb
update the bdp for the other fragment
update txq->cur_tx
fec_enet_tx_queue
bdp = fec_enet_get_nextdesc(txq->dirty_tx, fep, queue_id);
This bdp is the bdp reserved for the first segment. Given
that this bdp BD_ENET_TX_READY bit is not set and txq->cur_tx
is already pointed to a bdp beyond this one. We think this is a
completed bdp and try to reclaim it.
update the bdp for the first segment
update txq->cur_tx
So we shouldn't update the txq->cur_tx until all the update to the
bdps used for fragments are performed. Also add the corresponding
memory barrier to guarantee that the update to the bdps, dirty_tx and
cur_tx performed in the proper order.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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|---|---|---|
| .. | ||
| fs_enet | ||
| fec_main.c | ||
| fec_mpc52xx_phy.c | ||
| fec_mpc52xx.c | ||
| fec_mpc52xx.h | ||
| fec_ptp.c | ||
| fec.h | ||
| fsl_pq_mdio.c | ||
| gianfar_ethtool.c | ||
| gianfar_ptp.c | ||
| gianfar.c | ||
| gianfar.h | ||
| Kconfig | ||
| Makefile | ||
| ucc_geth_ethtool.c | ||
| ucc_geth.c | ||
| ucc_geth.h | ||
| xgmac_mdio.c | ||