netdev - [PATCH net-next] bnx2: Close device if tx

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Message-ID: <1310748838-30877-1-git-send-email-mchan@broadcom.com>
Date:	Fri, 15 Jul 2011 09:53:58 -0700
From:	"Michael Chan" <mchan@...adcom.com>
To:	davem@...emloft.net
cc:	netdev@...r.kernel.org, fbl@...hat.com
Subject: [PATCH net-next] bnx2: Close device if tx_timeout reset fails

Based on original patch and description from Flavio Leitner <fbl@...hat.com>

When bnx2_reset_task() is called, it will stop,
(re)initialize and start the interface to restore
the working condition.

The bnx2_init_nic() calls bnx2_reset_nic() which will
reset the chip and then calls bnx2_free_skbs() to free
all the skbs.

The problem happens when bnx2_init_chip() fails because
bnx2_reset_nic() will just return skipping the ring
initializations at bnx2_init_all_rings(). Later, the
reset task starts the interface again and the system
crashes due a NULL pointer access (no skb in the ring).

To fix it, we call dev_close() if bnx2_init_nic() fails.
One minor wrinkle to deal with is the cancel_work_sync()
call in bnx2_close() to cancel bnx2_reset_task().  The
call will wait forever because it is trying to cancel
itself and the workqueue will be stuck.

Since bnx2_reset_task() holds the rtnl_lock() and checks
for netif_running() before proceeding, there is no need
to cancel bnx2_reset_task() in bnx2_close() even if
bnx2_close() and bnx2_reset_task() are running concurrently.
The rtnl_lock() serializes the 2 calls.

We need to move the cancel_work_sync() call to
bnx2_remove_one() to make sure it is canceled before freeing
the netdev struct.

Signed-off-by: Michael Chan <mchan@...adcom.com>
Signed-off-by: Matt Carlson <mcarlson@...adcom.com>
Cc: Flavio Leitner <fbl@...hat.com>
---
 drivers/net/bnx2.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 4816d6a..3ad9b70 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -6342,6 +6342,7 @@ static void
 bnx2_reset_task(struct work_struct *work)
 {
 	struct bnx2 *bp = container_of(work, struct bnx2, reset_task);
+	int rc;

 	rtnl_lock();
 	if (!netif_running(bp->dev)) {
@@ -6351,7 +6352,14 @@ bnx2_reset_task(struct work_struct *work)

 	bnx2_netif_stop(bp, true);

-	bnx2_init_nic(bp, 1);
+	rc = bnx2_init_nic(bp, 1);
+	if (rc) {
+		netdev_err(bp->dev, "failed to reset NIC, closing\n");
+		bnx2_napi_enable(bp);
+		dev_close(bp->dev);
+		rtnl_unlock();
+		return;
+	}

 	atomic_set(&bp->intr_sem, 1);
 	bnx2_netif_start(bp, true);
@@ -6573,8 +6581,6 @@ bnx2_close(struct net_device *dev)
 {
 	struct bnx2 *bp = netdev_priv(dev);

-	cancel_work_sync(&bp->reset_task);
-
 	bnx2_disable_int_sync(bp);
 	bnx2_napi_disable(bp);
 	del_timer_sync(&bp->timer);
@@ -8404,6 +8410,7 @@ bnx2_remove_one(struct pci_dev *pdev)
 	unregister_netdev(dev);

 	del_timer_sync(&bp->timer);
+	cancel_work_sync(&bp->reset_task);

 	if (bp->mips_firmware)
 		release_firmware(bp->mips_firmware);
-- 
1.6.4.GIT

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