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Message-Id: <20071121060729.71A1FDDE01@ozlabs.org>
Date: Wed, 21 Nov 2007 17:06:39 +1100
From: Benjamin Herrenschmidt <benh@...nel.crashing.org>
To: <jgarzik@...ox.com>
CC: <netdev@...r.kernel.org>, <linuxppc-dev@...abs.org>,
Josh Boyer <jwboyer@...ux.vnet.ibm.com>
Subject: [PATCH 1/8] ibm_newemac: Fix possible lockup on close
It's a bad idea to call flush_scheduled_work from within a
netdev->stop because the linkwatch will occasionally take the
rtnl lock from a workqueue context, and thus that can deadlock.
This reworks things a bit in that area to avoid the problem.
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
---
drivers/net/ibm_newemac/core.c | 31 ++++++++++++++++++++-----------
drivers/net/ibm_newemac/core.h | 1 +
2 files changed, 21 insertions(+), 11 deletions(-)
Index: linux-work/drivers/net/ibm_newemac/core.c
===================================================================
--- linux-work.orig/drivers/net/ibm_newemac/core.c 2007-11-20 14:42:50.000000000 +1100
+++ linux-work/drivers/net/ibm_newemac/core.c 2007-11-20 14:46:51.000000000 +1100
@@ -642,9 +642,11 @@ static void emac_reset_work(struct work_
DBG(dev, "reset_work" NL);
mutex_lock(&dev->link_lock);
- emac_netif_stop(dev);
- emac_full_tx_reset(dev);
- emac_netif_start(dev);
+ if (dev->opened) {
+ emac_netif_stop(dev);
+ emac_full_tx_reset(dev);
+ emac_netif_start(dev);
+ }
mutex_unlock(&dev->link_lock);
}
@@ -1063,10 +1065,9 @@ static int emac_open(struct net_device *
dev->rx_sg_skb = NULL;
mutex_lock(&dev->link_lock);
+ dev->opened = 1;
- /* XXX Start PHY polling now. Shouldn't wr do like sungem instead and
- * always poll the PHY even when the iface is down ? That would allow
- * things like laptop-net to work. --BenH
+ /* Start PHY polling now.
*/
if (dev->phy.address >= 0) {
int link_poll_interval;
@@ -1145,9 +1146,11 @@ static void emac_link_timer(struct work_
int link_poll_interval;
mutex_lock(&dev->link_lock);
-
DBG2(dev, "link timer" NL);
+ if (!dev->opened)
+ goto bail;
+
if (dev->phy.def->ops->poll_link(&dev->phy)) {
if (!netif_carrier_ok(dev->ndev)) {
/* Get new link parameters */
@@ -1170,13 +1173,14 @@ static void emac_link_timer(struct work_
link_poll_interval = PHY_POLL_LINK_OFF;
}
schedule_delayed_work(&dev->link_work, link_poll_interval);
-
+ bail:
mutex_unlock(&dev->link_lock);
}
static void emac_force_link_update(struct emac_instance *dev)
{
netif_carrier_off(dev->ndev);
+ smp_rmb();
if (dev->link_polling) {
cancel_rearming_delayed_work(&dev->link_work);
if (dev->link_polling)
@@ -1191,11 +1195,14 @@ static int emac_close(struct net_device
DBG(dev, "close" NL);
- if (dev->phy.address >= 0)
+ if (dev->phy.address >= 0) {
+ dev->link_polling = 0;
cancel_rearming_delayed_work(&dev->link_work);
-
+ }
+ mutex_lock(&dev->link_lock);
emac_netif_stop(dev);
- flush_scheduled_work();
+ dev->opened = 0;
+ mutex_unlock(&dev->link_lock);
emac_rx_disable(dev);
emac_tx_disable(dev);
@@ -2756,6 +2763,8 @@ static int __devexit emac_remove(struct
unregister_netdev(dev->ndev);
+ flush_scheduled_work();
+
if (emac_has_feature(dev, EMAC_FTR_HAS_TAH))
tah_detach(dev->tah_dev, dev->tah_port);
if (emac_has_feature(dev, EMAC_FTR_HAS_RGMII))
Index: linux-work/drivers/net/ibm_newemac/core.h
===================================================================
--- linux-work.orig/drivers/net/ibm_newemac/core.h 2007-11-20 14:42:50.000000000 +1100
+++ linux-work/drivers/net/ibm_newemac/core.h 2007-11-20 14:46:51.000000000 +1100
@@ -258,6 +258,7 @@ struct emac_instance {
int stop_timeout; /* in us */
int no_mcast;
int mcast_pending;
+ int opened;
struct work_struct reset_work;
spinlock_t lock;
};
-
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