From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Thu, 25 Apr 2019 20:42:45 +0800
Subject: net: hns3: fix data race between ring->next_to_clean
Patch-mainline: v5.2-rc1
Git-commit: 26cda2f1613878d9bde11325559f4fca92fff395
References: bsc#1104353 FATE#326415 bsc#1134975 bsc#1134945
hns3_clean_tx_ring calls hns3_nic_reclaim_one_desc to clean
buffers and set ring->next_to_clean, then hns3_nic_net_xmit
reuses the cleaned buffers. But there are no memory barriers
when buffers gets recycled, so the recycled buffers can be
corrupted.
This patch uses smp_store_release to update ring->next_to_clean
and smp_load_acquire to read ring->next_to_clean to properly
hand off buffers from hns3_clean_tx_ring to hns3_nic_net_xmit.
Fixes: 76ad4f0ee747 ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 14 +++++++++++---
drivers/net/ethernet/hisilicon/hns3/hns3_enet.h | 7 +++++--
2 files changed, 16 insertions(+), 5 deletions(-)
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -2215,14 +2215,22 @@ static void hns3_reuse_buffer(struct hns
static void hns3_nic_reclaim_one_desc(struct hns3_enet_ring *ring, int *bytes,
int *pkts)
{
- struct hns3_desc_cb *desc_cb = &ring->desc_cb[ring->next_to_clean];
+ int ntc = ring->next_to_clean;
+ struct hns3_desc_cb *desc_cb;
+ desc_cb = &ring->desc_cb[ntc];
(*pkts) += (desc_cb->type == DESC_TYPE_SKB);
(*bytes) += desc_cb->length;
/* desc_cb will be cleaned, after hnae3_free_buffer_detach*/
- hns3_free_buffer_detach(ring, ring->next_to_clean);
+ hns3_free_buffer_detach(ring, ntc);
- ring_ptr_move_fw(ring, next_to_clean);
+ if (++ntc == ring->desc_num)
+ ntc = 0;
+
+ /* This smp_store_release() pairs with smp_load_acquire() in
+ * ring_space called by hns3_nic_net_xmit.
+ */
+ smp_store_release(&ring->next_to_clean, ntc);
}
static int is_valid_clean_head(struct hns3_enet_ring *ring, int h)
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
@@ -581,8 +581,11 @@ union l4_hdr_info {
static inline int ring_space(struct hns3_enet_ring *ring)
{
- int begin = ring->next_to_clean;
- int end = ring->next_to_use;
+ /* This smp_load_acquire() pairs with smp_store_release() in
+ * hns3_nic_reclaim_one_desc called by hns3_clean_tx_ring.
+ */
+ int begin = smp_load_acquire(&ring->next_to_clean);
+ int end = READ_ONCE(ring->next_to_use);
return ((end >= begin) ? (ring->desc_num - end + begin) :
(begin - end)) - 1;