From: Eric Dumazet <eduma...@google.com>
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 <will...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Ariel Elior <ariel.el...@qlogic.com>
---
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 51 +++++---------
1 file 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 f6634a524153..d7cc2aa7c37a 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
--
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