[PATCH 5.14 008/169] r8152: avoid to resubmit rx immediately

Greg Kroah-Hartman
2021-10-25T19:46:49Z

From: Hayes Wang <hayeswang@realtek.com>

[ Upstream commit baf33d7a75642b4b38a87fdf1cd96b506df4849f ]

For the situation that the disconnect event comes very late when the
device is unplugged, the driver would resubmit the RX bulk transfer
after getting the callback with -EPROTO immediately and continually.
Finally, soft lockup occurs.

This patch avoids to resubmit RX immediately. It uses a workqueue to
schedule the RX NAPI. And the NAPI would resubmit the RX. It let the
disconnect event have opportunity to stop the submission before soft
lockup.

Reported-by: Jason-ch Chen <jason-ch.chen@mediatek.com>
Tested-by: Jason-ch Chen <jason-ch.chen@mediatek.com>
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/r8152.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 79832374f78d..92fca5e9ed03 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -767,6 +767,7 @@ enum rtl8152_flags {
PHY_RESET,
SCHEDULE_TASKLET,
GREEN_ETHERNET,
+ RX_EPROTO,
};

#define DEVICE_ID_THINKPAD_THUNDERBOLT3_DOCK_GEN2 0x3082
@@ -1770,6 +1771,14 @@ static void read_bulk_callback(struct urb *urb)
rtl_set_unplug(tp);
netif_device_detach(tp->netdev);
return;
+ case -EPROTO:
+ urb->actual_length = 0;
+ spin_lock_irqsave(&tp->rx_lock, flags);
+ list_add_tail(&agg->list, &tp->rx_done);
+ spin_unlock_irqrestore(&tp->rx_lock, flags);
+ set_bit(RX_EPROTO, &tp->flags);
+ schedule_delayed_work(&tp->schedule, 1);
+ return;
case -ENOENT:
return; /* the urb is in unlink state */
case -ETIME:
@@ -2425,6 +2434,7 @@ static int rx_bottom(struct r8152 *tp, int budget)
if (list_empty(&tp->rx_done))
goto out1;

+ clear_bit(RX_EPROTO, &tp->flags);
INIT_LIST_HEAD(&rx_queue);
spin_lock_irqsave(&tp->rx_lock, flags);
list_splice_init(&tp->rx_done, &rx_queue);
@@ -2441,7 +2451,7 @@ static int rx_bottom(struct r8152 *tp, int budget)

agg = list_entry(cursor, struct rx_agg, list);
urb = agg->urb;
- if (urb->actual_length < ETH_ZLEN)
+ if (urb->status != 0 || urb->actual_length < ETH_ZLEN)
goto submit;

agg_free = rtl_get_free_rx(tp, GFP_ATOMIC);
@@ -6643,6 +6653,10 @@ static void rtl_work_func_t(struct work_struct *work)
netif_carrier_ok(tp->netdev))
tasklet_schedule(&tp->tx_tl);

+ if (test_and_clear_bit(RX_EPROTO, &tp->flags) &&
+ !list_empty(&tp->rx_done))
+ napi_schedule(&tp->napi);
+
mutex_unlock(&tp->control);

out1:
--
2.33.0