[PATCH V2 for-next 1/8] net: hns: fix port unavailable after hnae_reserve_buffer_map fail

From: Salil Mehta
Date: Thu Sep 29 2016 - 13:11:49 EST


From: lipeng <lipeng321@xxxxxxxxxx>

When hnae_reserve_buffer_map fail, it will break cycle and some
buffer description has no available memory, therefore the port will
be unavailable.

Signed-off-by: Peng Li <lipeng321@xxxxxxxxxx>
Reviewed-by: Yisen Zhuang <yisen.zhuang@xxxxxxxxxx>
Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
---
drivers/net/ethernet/hisilicon/hns/hns_enet.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index d7e1f8c..32ff270 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -747,6 +747,14 @@ static void hns_nic_rx_up_pro(struct hns_nic_ring_data *ring_data,
ndev->last_rx = jiffies;
}

+static int hns_desc_unused(struct hnae_ring *ring)
+{
+ int ntc = ring->next_to_clean;
+ int ntu = ring->next_to_use;
+
+ return ((ntc >= ntu) ? 0 : ring->desc_num) + ntc - ntu;
+}
+
static int hns_nic_rx_poll_one(struct hns_nic_ring_data *ring_data,
int budget, void *v)
{
@@ -755,17 +763,21 @@ static int hns_nic_rx_poll_one(struct hns_nic_ring_data *ring_data,
int num, bnum, ex_num;
#define RCB_NOF_ALLOC_RX_BUFF_ONCE 16
int recv_pkts, recv_bds, clean_count, err;
+ int unused_count = hns_desc_unused(ring);

num = readl_relaxed(ring->io_base + RCB_REG_FBDNUM);
rmb(); /* make sure num taken effect before the other data is touched */

recv_pkts = 0, recv_bds = 0, clean_count = 0;
+ num -= unused_count;
recv:
while (recv_pkts < budget && recv_bds < num) {
/* reuse or realloc buffers */
- if (clean_count >= RCB_NOF_ALLOC_RX_BUFF_ONCE) {
- hns_nic_alloc_rx_buffers(ring_data, clean_count);
+ if (clean_count + unused_count >= RCB_NOF_ALLOC_RX_BUFF_ONCE) {
+ hns_nic_alloc_rx_buffers(ring_data,
+ clean_count + unused_count);
clean_count = 0;
+ unused_count = hns_desc_unused(ring);
}

/* poll one pkt */
@@ -789,7 +801,7 @@ recv:
/* make all data has been write before submit */
if (recv_pkts < budget) {
ex_num = readl_relaxed(ring->io_base + RCB_REG_FBDNUM);
-
+ ex_num -= unused_count;
if (ex_num > clean_count) {
num += ex_num - clean_count;
rmb(); /*complete read rx ring bd number*/
@@ -799,8 +811,9 @@ recv:

out:
/* make all data has been write before submit */
- if (clean_count > 0)
- hns_nic_alloc_rx_buffers(ring_data, clean_count);
+ if (clean_count + unused_count > 0)
+ hns_nic_alloc_rx_buffers(ring_data,
+ clean_count + unused_count);

return recv_pkts;
}
--
1.7.9.5