Messages in this thread | | | Subject | Re: [PATCH v2] xen-netfront: Improve error handling during initialization | From | Ross Lagerwall <> | Date | Wed, 8 Feb 2017 10:32:59 +0000 |
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On 02/07/2017 11:33 PM, Boris Ostrovsky wrote: > On 02/07/2017 09:55 AM, Ross Lagerwall wrote: >> This fixes a crash when running out of grant refs when creating many >> queues across many netdevs. >> >> * If creating queues fails (i.e. there are no grant refs available), >> call xenbus_dev_fatal() to ensure that the xenbus device is set to the >> closed state. >> * If no queues are created, don't call xennet_disconnect_backend as >> netdev->real_num_tx_queues will not have been set correctly. >> * If setup_netfront() fails, ensure that all the queues created are >> cleaned up, not just those that have been set up. >> * If any queues were set up and an error occurs, call >> xennet_destroy_queues() to clean up the napi context. >> * If any fatal error occurs, unregister and destroy the netdev to avoid >> leaving around a half setup network device. >> >> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> >> --- >> >> Changed in V2: >> * Retested on top of v4.10-rc7 + "xen-netfront: Delete rx_refill_timer >> in xennet_disconnect_backend()". >> * Don't move setup_timer as it is not necessary. >> >> drivers/net/xen-netfront.c | 33 +++++++++++++++------------------ >> 1 file changed, 15 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c >> index 722fe9f..5399a86 100644 >> --- a/drivers/net/xen-netfront.c >> +++ b/drivers/net/xen-netfront.c >> @@ -1823,27 +1823,23 @@ static int talk_to_netback(struct xenbus_device *dev, >> xennet_destroy_queues(info); >> >> err = xennet_create_queues(info, &num_queues); >> - if (err < 0) >> - goto destroy_ring; >> + if (err < 0) { >> + xenbus_dev_fatal(dev, err, "creating queues"); >> + if (num_queues > 0) { >> + goto destroy_ring; > > The only way for us to have (err<0) && (num_queues>0) is when we get a > -ENOMEM right at the top, isn't it? So there is nothing to disconnect or > destroy, it seems to me. And if that's true you can directly 'goto out'. >
You're right, although that might make it a bit more fragile if something in xennet_create_queues() changes in the future. Nevertheless, I'll update the patch.
-- Ross Lagerwall
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