From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Subject: [PATCH 4/4] iseries_veth: Cleanup skbs to prevent unregister_netdevice() hanging Date: Thu, 12 May 2005 18:09:45 +1000 Message-ID: <200505121809.45419.michael@ellerman.id.au> Reply-To: michael@ellerman.id.au Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com, linux-kernel@vger.kernel.org, PPC64-dev Return-path: To: Andrew Morton , Jeff Garzik Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc64-dev-bounces@ozlabs.org Errors-To: linuxppc64-dev-bounces@ozlabs.org List-Id: netdev.vger.kernel.org Hi Andrew, Jeff, The iseries_veth driver is badly behaved in that it will keep TX packets hanging around forever if they're not ACK'ed and the queue never fills up. This causes the unregister_netdevice code to wait forever when we try to take the device down, because there's still skbs around with references to our struct net_device. There's already code to cleanup any un-ACK'ed packets in veth_stop_connection() but it's being called after we unregister the net_device, which is too late. The fix is to rearrange the module exit function so that we cleanup any outstanding skbs and then unregister the driver. Signed-off-by: Michael Ellerman -- drivers/net/iseries_veth.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) Index: veth-fixes/drivers/net/iseries_veth.c =================================================================== --- veth-fixes.orig/drivers/net/iseries_veth.c 2005-05-12 16:27:32.000000000 +1000 +++ veth-fixes/drivers/net/iseries_veth.c 2005-05-12 16:27:42.000000000 +1000 @@ -1388,18 +1388,25 @@ { int i; - vio_unregister_driver(&veth_driver); + /* Stop the queues first to stop any new packets being sent. */ + for (i = 0; i < HVMAXARCHITECTEDVIRTUALLANS; i++) + if (veth_dev[i]) + netif_stop_queue(veth_dev[i]); + /* Stop the connections before we unregister the driver. This + * ensures there's no skbs lying around holding the device open. */ for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) veth_stop_connection(i); HvLpEvent_unregisterHandler(HvLpEvent_Type_VirtualLan); /* Hypervisor callbacks may have scheduled more work while we - * were destroying connections. Now that we've disconnected from + * were stoping connections. Now that we've disconnected from * the hypervisor make sure everything's finished. */ flush_scheduled_work(); + vio_unregister_driver(&veth_driver); + for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) veth_destroy_connection(i);