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xen-netback: enable user to unload netback module
This patch enables user to unload netback module, which is useful when user wants to upgrade to a newer netback module without rebooting the host. Netfront cannot handle netback removal event. As we cannot fix all possible frontends we add module get / put along with vif get / put to avoid mis-unloading of netback. To unload netback module, user needs to shutdown all VMs or migrate them to another host or unplug all vifs before hand. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com>¬ Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
f1db320ec5
commit
b103f358d9
4 changed files with 44 additions and 1 deletions
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@ -120,6 +120,7 @@ void xenvif_get(struct xenvif *vif);
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void xenvif_put(struct xenvif *vif);
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int xenvif_xenbus_init(void);
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void xenvif_xenbus_fini(void);
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int xenvif_schedulable(struct xenvif *vif);
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@ -316,6 +316,8 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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if (vif->irq)
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return 0;
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__module_get(THIS_MODULE);
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err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
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if (err < 0)
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goto err;
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@ -343,6 +345,7 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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err_unmap:
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xen_netbk_unmap_frontend_rings(vif);
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err:
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module_put(THIS_MODULE);
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return err;
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}
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@ -360,18 +363,32 @@ void xenvif_carrier_off(struct xenvif *vif)
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void xenvif_disconnect(struct xenvif *vif)
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{
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/* Disconnect funtion might get called by generic framework
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* even before vif connects, so we need to check if we really
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* need to do a module_put.
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*/
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int need_module_put = 0;
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if (netif_carrier_ok(vif->dev))
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xenvif_carrier_off(vif);
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atomic_dec(&vif->refcnt);
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wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
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if (vif->irq)
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if (vif->irq) {
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unbind_from_irqhandler(vif->irq, vif);
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/* vif->irq is valid, we had a module_get in
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* xenvif_connect.
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*/
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need_module_put = 1;
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}
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unregister_netdev(vif->dev);
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xen_netbk_unmap_frontend_rings(vif);
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free_netdev(vif->dev);
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if (need_module_put)
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module_put(THIS_MODULE);
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}
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@ -1949,5 +1949,25 @@ static int __init netback_init(void)
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module_init(netback_init);
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static void __exit netback_fini(void)
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{
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int i, j;
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xenvif_xenbus_fini();
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for (i = 0; i < xen_netbk_group_nr; i++) {
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struct xen_netbk *netbk = &xen_netbk[i];
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del_timer_sync(&netbk->net_timer);
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kthread_stop(netbk->task);
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for (j = 0; j < MAX_PENDING_REQS; j++) {
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if (netbk->mmap_pages[i])
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__free_page(netbk->mmap_pages[i]);
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}
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}
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vfree(xen_netbk);
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}
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module_exit(netback_fini);
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_ALIAS("xen-backend:vif");
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@ -485,3 +485,8 @@ int xenvif_xenbus_init(void)
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{
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return xenbus_register_backend(&netback_driver);
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}
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void xenvif_xenbus_fini(void)
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{
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return xenbus_unregister_driver(&netback_driver);
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}
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