blob: 48bf4b1d238abf2a0884b66c4d85da1f1ecc6add [file] [log] [blame]
From c5f9476596ff0e82290fa478de0c1e345d7ea579 Mon Sep 17 00:00:00 2001
From: Marek Vasut <>
Date: Sun, 23 Feb 2020 14:38:40 +0100
Subject: [PATCH] net: ks8851-ml: Fix IRQ handling and locking
commit 44343418d0f2f623cb9da6f5000df793131cbe3b upstream.
The KS8851 requires that packet RX and TX are mutually exclusive.
Currently, the driver hopes to achieve this by disabling interrupt
from the card by writing the card registers and by disabling the
interrupt on the interrupt controller. This however is racy on SMP.
Replace this approach by expanding the spinlock used around the
ks_start_xmit() TX path to ks_irq() RX path to assure true mutual
exclusion and remove the interrupt enabling/disabling, which is
now not needed anymore. Furthermore, disable interrupts also in
ks_net_stop(), which was missing before.
Note that a massive improvement here would be to re-use the KS8851
driver approach, which is to move the TX path into a worker thread,
interrupt handling to threaded interrupt, and synchronize everything
with mutexes, but that would be a much bigger rework, for a separate
Signed-off-by: Marek Vasut <>
Cc: David S. Miller <>
Cc: Lukas Wunner <>
Cc: Petr Stetiar <>
Cc: YueHaibing <>
Signed-off-by: David S. Miller <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/net/ethernet/micrel/ks8851_mll.c b/drivers/net/ethernet/micrel/ks8851_mll.c
index 2cfdfccb60c3..c08e8e154d9c 100644
--- a/drivers/net/ethernet/micrel/ks8851_mll.c
+++ b/drivers/net/ethernet/micrel/ks8851_mll.c
@@ -513,14 +513,17 @@ static irqreturn_t ks_irq(int irq, void *pw)
struct net_device *netdev = pw;
struct ks_net *ks = netdev_priv(netdev);
+ unsigned long flags;
u16 status;
+ spin_lock_irqsave(&ks->statelock, flags);
/*this should be the first in IRQ handler */
status = ks_rdreg16(ks, KS_ISR);
if (unlikely(!status)) {
+ spin_unlock_irqrestore(&ks->statelock, flags);
return IRQ_NONE;
@@ -546,6 +549,7 @@ static irqreturn_t ks_irq(int irq, void *pw)
/* this should be the last in IRQ handler*/
+ spin_unlock_irqrestore(&ks->statelock, flags);
@@ -615,6 +619,7 @@ static int ks_net_stop(struct net_device *netdev)
/* shutdown RX/TX QMU */
+ ks_disable_int(ks);
/* set powermode to soft power down to save power */
ks_set_powermode(ks, PMECR_PM_SOFTDOWN);
@@ -671,10 +676,9 @@ static netdev_tx_t ks_start_xmit(struct sk_buff *skb, struct net_device *netdev)
netdev_tx_t retv = NETDEV_TX_OK;
struct ks_net *ks = netdev_priv(netdev);
+ unsigned long flags;
- disable_irq(netdev->irq);
- ks_disable_int(ks);
- spin_lock(&ks->statelock);
+ spin_lock_irqsave(&ks->statelock, flags);
/* Extra space are required:
* 4 byte for alignment, 4 for status/length, 4 for CRC
@@ -688,9 +692,7 @@ static netdev_tx_t ks_start_xmit(struct sk_buff *skb, struct net_device *netdev)
} else
- spin_unlock(&ks->statelock);
- ks_enable_int(ks);
- enable_irq(netdev->irq);
+ spin_unlock_irqrestore(&ks->statelock, flags);
return retv;