From 5dd2f85c9e5862d0165495d716b78a00ebb533dd Mon Sep 17 00:00:00 2001
From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Thu, 18 Nov 2021 20:44:39 +0800
Subject: [PATCH 141/283] net: hns3: schedule the polling again when allocation
 fails

mainline inclusion
from mainline-v5.15-rc7
commit 68752b24f51a71d4f350a764d890b670f59062c5
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I8EMYT
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=68752b24f51a71d4f350a764d890b670f59062c5

----------------------------------------------------------------------

Currently when there is a rx page allocation failure, it is
possible that polling may be stopped if there is no more packet
to be reveiced, which may cause queue stall problem under memory
pressure.

This patch makes sure polling is scheduled again when there is
any rx page allocation failure, and polling will try to allocate
receive buffers until it succeeds.

Now the allocation retry is added, it is unnecessary to do the rx
page allocation at the end of rx cleaning, so remove it. And reset
the unused_count to zero after calling hns3_nic_alloc_rx_buffers()
to avoid calling hns3_nic_alloc_rx_buffers() repeatedly under
memory pressure.

Fixes: 76ad4f0ee747 ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Yongxin Li <liyongxin1@huawei.com>
Signed-off-by: Junxin Chen <chenjunxin1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Xiaodong Li <lixiaodong67@huawei.com>
---
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 9acb48ff8c6f..69170427c55d 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -3158,7 +3158,8 @@ static int hns3_desc_unused(struct hns3_enet_ring *ring)
 	return ((ntc >= ntu) ? 0 : ring->desc_num) + ntc - ntu;
 }
 
-static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
+/* Return true if there is any allocation failure */
+static bool hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
 				      int cleand_count)
 {
 	struct hns3_desc_cb *desc_cb;
@@ -3183,7 +3184,10 @@ static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
 				hns3_rl_err(ring_to_netdev(ring),
 					    "alloc rx buffer failed: %d\n",
 					    ret);
-				break;
+
+				writel(i, ring->tqp->io_base +
+				       HNS3_RING_RX_RING_HEAD_REG);
+				return true;
 			}
 			hns3_replace_buffer(ring, ring->next_to_use, &res_cbs);
 
@@ -3196,6 +3200,7 @@ static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
 	}
 
 	writel(i, ring->tqp->io_base + HNS3_RING_RX_RING_HEAD_REG);
+	return false;
 }
 
 static bool hns3_page_is_reusable(struct page *page)
@@ -3807,6 +3812,7 @@ int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 {
 #define RCB_NOF_ALLOC_RX_BUFF_ONCE 16
 	int unused_count = hns3_desc_unused(ring);
+	bool failure = false;
 	int recv_pkts = 0;
 	int err;
 
@@ -3815,9 +3821,9 @@ int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 	while (recv_pkts < budget) {
 		/* Reuse or realloc buffers */
 		if (unused_count >= RCB_NOF_ALLOC_RX_BUFF_ONCE) {
-			hns3_nic_alloc_rx_buffers(ring, unused_count);
-			unused_count = hns3_desc_unused(ring) -
-					ring->pending_buf;
+			failure = failure ||
+				hns3_nic_alloc_rx_buffers(ring, unused_count);
+			unused_count = 0;
 		}
 
 		/* Poll one pkt */
@@ -3836,11 +3842,7 @@ int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 	}
 
 out:
-	/* Make all data has been write before submit */
-	if (unused_count > 0)
-		hns3_nic_alloc_rx_buffers(ring, unused_count);
-
-	return recv_pkts;
+	return failure ? budget : recv_pkts;
 }
 
 static bool hns3_get_new_flow_lvl(struct hns3_enet_ring_group *ring_group)
-- 
2.34.1

