linux-kernel - [PATCH 4.9 068/108] r8152: avoid start_xmit to call napi

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Message-Id: <20170615175340.415752288@linuxfoundation.org>
Date:   Thu, 15 Jun 2017 19:53:14 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hayes Wang <hayeswang@...ltek.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.9 068/108] r8152: avoid start_xmit to call napi_schedule during autosuspend

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: hayeswang <hayeswang@...ltek.com>


[ Upstream commit 26afec39306926654e9cd320f19bbf3685bb0997 ]

Adjust the setting of the flag of SELECTIVE_SUSPEND to prevent start_xmit()
from calling napi_schedule() directly during runtime suspend.

After calling napi_disable() or clearing the flag of WORK_ENABLE,
scheduling the napi is useless.

Signed-off-by: Hayes Wang <hayeswang@...ltek.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/usb/r8152.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -3583,10 +3583,15 @@ static int rtl8152_rumtime_suspend(struc
 	struct net_device *netdev = tp->netdev;
 	int ret = 0;
 
+	set_bit(SELECTIVE_SUSPEND, &tp->flags);
+	smp_mb__after_atomic();
+
 	if (netif_running(netdev) && test_bit(WORK_ENABLE, &tp->flags)) {
 		u32 rcr = 0;
 
 		if (delay_autosuspend(tp)) {
+			clear_bit(SELECTIVE_SUSPEND, &tp->flags);
+			smp_mb__after_atomic();
 			ret = -EBUSY;
 			goto out1;
 		}
@@ -3603,6 +3608,8 @@ static int rtl8152_rumtime_suspend(struc
 			if (!(ocp_data & RXFIFO_EMPTY)) {
 				rxdy_gated_en(tp, false);
 				ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RCR, rcr);
+				clear_bit(SELECTIVE_SUSPEND, &tp->flags);
+				smp_mb__after_atomic();
 				ret = -EBUSY;
 				goto out1;
 			}
@@ -3622,8 +3629,6 @@ static int rtl8152_rumtime_suspend(struc
 		}
 	}
 
-	set_bit(SELECTIVE_SUSPEND, &tp->flags);
-
 out1:
 	return ret;
 }
@@ -3679,12 +3684,13 @@ static int rtl8152_resume(struct usb_int
 	if (netif_running(tp->netdev) && tp->netdev->flags & IFF_UP) {
 		if (test_bit(SELECTIVE_SUSPEND, &tp->flags)) {
 			tp->rtl_ops.autosuspend_en(tp, false);
-			clear_bit(SELECTIVE_SUSPEND, &tp->flags);
 			napi_disable(&tp->napi);
 			set_bit(WORK_ENABLE, &tp->flags);
 			if (netif_carrier_ok(tp->netdev))
 				rtl_start_rx(tp);
 			napi_enable(&tp->napi);
+			clear_bit(SELECTIVE_SUSPEND, &tp->flags);
+			smp_mb__after_atomic();
 		} else {
 			tp->rtl_ops.up(tp);
 			netif_carrier_off(tp->netdev);