[PATCH 1/1] net-next: hinic: fix a problem in free_tx_poll()

From: Zhao Chen
Date: Wed Aug 08 2018 - 10:33:11 EST


This patch fixes the problem below. The problem can be reproduced by the
following steps:
1) Connecting all HiNIC interfaces
2) On server side
# sudo ifconfig eth0 192.168.100.1 up #Using MLX CX4 card
# iperf -s
3) On client side
# sudo ifconfig eth0 192.168.100.2 up #Using our HiNIC card
# iperf -c 192.168.101.1 -P 10 -t 100000

after hours of testing, we will see errors:

hinic 0000:05:00.0: No MGMT msg handler, mod = 0
hinic 0000:05:00.0: No MGMT msg handler, mod = 0
hinic 0000:05:00.0: No MGMT msg handler, mod = 0
hinic 0000:05:00.0: No MGMT msg handler, mod = 0

The errors are caused by the following problem.
1) The hinic_get_wqe() checks the "wq->delta" to allocate new WQEs:

if (atomic_sub_return(num_wqebbs, &wq->delta) <= 0) {
atomic_add(num_wqebbs, &wq->delta);
return ERR_PTR(-EBUSY);
}

If the WQE occupies multiple pages, the shadow WQE will be used. Then the
hinic_xmit_frame() fills the WQE.

2) While in parallel with 1), the free_tx_poll() checks the "wq->delta"
to free old WQEs:

if ((atomic_read(&wq->delta) + num_wqebbs) > wq->q_depth)
return ERR_PTR(-EBUSY);

There is a probability that the shadow WQE which hinic_xmit_frame() is
using will be damaged by copy_wqe_to_shadow():

if (curr_pg != end_pg) {
void *shadow_addr = &wq->shadow_wqe[curr_pg * wq->max_wqe_size];

copy_wqe_to_shadow(wq, shadow_addr, num_wqebbs, *cons_idx);
return shadow_addr;
}

This can cause WQE data error and you will see the above error messages.
This patch fixes the problem.

Signed-off-by: Zhao Chen <zhaochen6@xxxxxxxxxx>
---
.../net/ethernet/huawei/hinic/hinic_hw_qp.c | 36 ++++++++++++++-----
.../net/ethernet/huawei/hinic/hinic_hw_qp.h | 6 +++-
drivers/net/ethernet/huawei/hinic/hinic_tx.c | 18 ++++++++--
3 files changed, 49 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.c b/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.c
index b9db6d649743..cb239627770f 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.c
@@ -635,17 +635,18 @@ void hinic_sq_write_wqe(struct hinic_sq *sq, u16 prod_idx,
}

/**
- * hinic_sq_read_wqe - read wqe ptr in the current ci and update the ci
+ * hinic_sq_read_wqebb - read wqe ptr in the current ci and update the ci, the
+ * wqe only have one wqebb
* @sq: send queue
* @skb: return skb that was saved
- * @wqe_size: the size of the wqe
+ * @wqe_size: the wqe size ptr
* @cons_idx: consumer index of the wqe
*
* Return wqe in ci position
**/
-struct hinic_sq_wqe *hinic_sq_read_wqe(struct hinic_sq *sq,
- struct sk_buff **skb,
- unsigned int *wqe_size, u16 *cons_idx)
+struct hinic_sq_wqe *hinic_sq_read_wqebb(struct hinic_sq *sq,
+ struct sk_buff **skb,
+ unsigned int *wqe_size, u16 *cons_idx)
{
struct hinic_hw_wqe *hw_wqe;
struct hinic_sq_wqe *sq_wqe;
@@ -658,6 +659,8 @@ struct hinic_sq_wqe *hinic_sq_read_wqe(struct hinic_sq *sq,
if (IS_ERR(hw_wqe))
return NULL;

+ *skb = sq->saved_skb[*cons_idx];
+
sq_wqe = &hw_wqe->sq_wqe;
ctrl = &sq_wqe->ctrl;
ctrl_info = be32_to_cpu(ctrl->ctrl_info);
@@ -665,11 +668,28 @@ struct hinic_sq_wqe *hinic_sq_read_wqe(struct hinic_sq *sq,

*wqe_size = sizeof(*ctrl) + sizeof(sq_wqe->task);
*wqe_size += SECT_SIZE_FROM_8BYTES(buf_sect_len);
+ *wqe_size = ALIGN(*wqe_size, sq->wq->wqebb_size);

- *skb = sq->saved_skb[*cons_idx];
+ return &hw_wqe->sq_wqe;
+}
+
+/**
+ * hinic_sq_read_wqe - read wqe ptr in the current ci and update the ci
+ * @sq: send queue
+ * @skb: return skb that was saved
+ * @wqe_size: the size of the wqe
+ * @cons_idx: consumer index of the wqe
+ *
+ * Return wqe in ci position
+ **/
+struct hinic_sq_wqe *hinic_sq_read_wqe(struct hinic_sq *sq,
+ struct sk_buff **skb,
+ unsigned int wqe_size, u16 *cons_idx)
+{
+ struct hinic_hw_wqe *hw_wqe;

- /* using the real wqe size to read wqe again */
- hw_wqe = hinic_read_wqe(sq->wq, *wqe_size, cons_idx);
+ hw_wqe = hinic_read_wqe(sq->wq, wqe_size, cons_idx);
+ *skb = sq->saved_skb[*cons_idx];

return &hw_wqe->sq_wqe;
}
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.h b/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.h
index df729a1587e9..6c84f83ec283 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.h
+++ b/drivers/net/ethernet/huawei/hinic/hinic_hw_qp.h
@@ -165,7 +165,11 @@ void hinic_sq_write_wqe(struct hinic_sq *sq, u16 prod_idx,

struct hinic_sq_wqe *hinic_sq_read_wqe(struct hinic_sq *sq,
struct sk_buff **skb,
- unsigned int *wqe_size, u16 *cons_idx);
+ unsigned int wqe_size, u16 *cons_idx);
+
+struct hinic_sq_wqe *hinic_sq_read_wqebb(struct hinic_sq *sq,
+ struct sk_buff **skb,
+ unsigned int *wqe_size, u16 *cons_idx);

void hinic_sq_put_wqe(struct hinic_sq *sq, unsigned int wqe_size);

diff --git a/drivers/net/ethernet/huawei/hinic/hinic_tx.c b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
index 2353ec829c04..c5fca0356c9c 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_tx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
@@ -283,7 +283,11 @@ static void free_all_tx_skbs(struct hinic_txq *txq)
int nr_sges;
u16 ci;

- while ((sq_wqe = hinic_sq_read_wqe(sq, &skb, &wqe_size, &ci))) {
+ while ((sq_wqe = hinic_sq_read_wqebb(sq, &skb, &wqe_size, &ci))) {
+ sq_wqe = hinic_sq_read_wqe(sq, &skb, wqe_size, &ci);
+ if (!sq_wqe)
+ break;
+
nr_sges = skb_shinfo(skb)->nr_frags + 1;

hinic_sq_get_sges(sq_wqe, txq->free_sges, nr_sges);
@@ -319,11 +323,21 @@ static int free_tx_poll(struct napi_struct *napi, int budget)
do {
hw_ci = HW_CONS_IDX(sq) & wq->mask;

- sq_wqe = hinic_sq_read_wqe(sq, &skb, &wqe_size, &sw_ci);
+ /* Reading a WQEBB to get real WQE size and consumer index. */
+ sq_wqe = hinic_sq_read_wqebb(sq, &skb, &wqe_size, &sw_ci);
if ((!sq_wqe) ||
(((hw_ci - sw_ci) & wq->mask) * wq->wqebb_size < wqe_size))
break;

+ /* If this WQE have multiple WQEBBs, we will read again to get
+ * full size WQE.
+ */
+ if (wqe_size > wq->wqebb_size) {
+ sq_wqe = hinic_sq_read_wqe(sq, &skb, wqe_size, &sw_ci);
+ if (unlikely(!sq_wqe))
+ break;
+ }
+
tx_bytes += skb->len;
pkts++;

--
2.17.1