diff options
author | Eric Dumazet <edumazet@google.com> | 2015-12-08 05:54:40 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2015-12-08 22:54:57 -0500 |
commit | 4d6acb62d2db5c1cc533c9a0b6e418ef9f63642e (patch) | |
tree | bbcb7ba4b5817c858fe41873c776e3500a8717e7 /drivers/net/ethernet/broadcom/bnx2x | |
parent | 46c749eac979c0bf280f760971367e9babe4d05f (diff) | |
download | op-kernel-dev-4d6acb62d2db5c1cc533c9a0b6e418ef9f63642e.zip op-kernel-dev-4d6acb62d2db5c1cc533c9a0b6e418ef9f63642e.tar.gz |
bnx2x: avoid soft lockup in bnx2x_poll()
Under heavy TX load, bnx2x_poll() can loop forever and trigger
soft lockup bugs.
A napi poll handler must yield after one TX completion round,
risk of livelock is too high otherwise.
Bug is very easy to trigger using a debug build, and udp flood, because
of added cpu cycles in TX completion, and we do not receive enough
packets to break the loop.
Reported-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/broadcom/bnx2x')
-rw-r--r-- | drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 51 |
1 files changed, 21 insertions, 30 deletions
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c index f6634a5..d7cc2aa 100644 --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c @@ -3204,42 +3204,32 @@ int bnx2x_set_power_state(struct bnx2x *bp, pci_power_t state) */ static int bnx2x_poll(struct napi_struct *napi, int budget) { - int work_done = 0; - u8 cos; struct bnx2x_fastpath *fp = container_of(napi, struct bnx2x_fastpath, napi); struct bnx2x *bp = fp->bp; + int rx_work_done; + u8 cos; - while (1) { #ifdef BNX2X_STOP_ON_ERROR - if (unlikely(bp->panic)) { - napi_complete(napi); - return 0; - } + if (unlikely(bp->panic)) { + napi_complete(napi); + return 0; + } #endif - for_each_cos_in_tx_queue(fp, cos) - if (bnx2x_tx_queue_has_work(fp->txdata_ptr[cos])) - bnx2x_tx_int(bp, fp->txdata_ptr[cos]); - - if (bnx2x_has_rx_work(fp)) { - work_done += bnx2x_rx_int(fp, budget - work_done); - - /* must not complete if we consumed full budget */ - if (work_done >= budget) - break; - } + for_each_cos_in_tx_queue(fp, cos) + if (bnx2x_tx_queue_has_work(fp->txdata_ptr[cos])) + bnx2x_tx_int(bp, fp->txdata_ptr[cos]); - /* Fall out from the NAPI loop if needed */ - if (!(bnx2x_has_rx_work(fp) || bnx2x_has_tx_work(fp))) { + rx_work_done = (bnx2x_has_rx_work(fp)) ? bnx2x_rx_int(fp, budget) : 0; - /* No need to update SB for FCoE L2 ring as long as - * it's connected to the default SB and the SB - * has been updated when NAPI was scheduled. - */ - if (IS_FCOE_FP(fp)) { - napi_complete(napi); - break; - } + if (rx_work_done < budget) { + /* No need to update SB for FCoE L2 ring as long as + * it's connected to the default SB and the SB + * has been updated when NAPI was scheduled. + */ + if (IS_FCOE_FP(fp)) { + napi_complete(napi); + } else { bnx2x_update_fpsb_idx(fp); /* bnx2x_has_rx_work() reads the status block, * thus we need to ensure that status block indices @@ -3264,12 +3254,13 @@ static int bnx2x_poll(struct napi_struct *napi, int budget) bnx2x_ack_sb(bp, fp->igu_sb_id, USTORM_ID, le16_to_cpu(fp->fp_hc_idx), IGU_INT_ENABLE, 1); - break; + } else { + rx_work_done = budget; } } } - return work_done; + return rx_work_done; } /* we split the first BD into headers and data BDs |