From: Duncan Sands Date: Fri, 13 Jan 2006 09:05:15 +0000 (+0100) Subject: [PATCH] USBATM: shutdown open connections when disconnected X-Git-Tag: v2.6.16-rc2~208 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e42a627ec3d8defa0c43cff94b8f2080a070716;p=linux-2.6 [PATCH] USBATM: shutdown open connections when disconnected This patch causes vcc_release_async to be applied to any open vcc's when the modem is disconnected. This signals a socket shutdown, letting the socket user know that the game is up. I wrote this patch because of reports that pppd would keep connections open forever when the modem is disconnected. This patch does not fix that problem, but it's a step in the right direction. It doesn't help because the pppoatm module doesn't yet monitor state changes on the ATM socket, so simply never realises that the ATM connection has gone down (meaning it doesn't tell the ppp layer). But at least there is a socket state change now. Unfortunately this patch may create problems for those rare users like me who use routed IP or some other non-ppp connection method that goes via the ATM ARP daemon: the daemon is buggy, and with this patch will crash when the modem is disconnected. Users with a buggy atmarpd can simply restart it after disconnecting the modem. Signed-off-by: Duncan Sands Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c index 3ed5f02c36..e660a1ebf1 100644 --- a/drivers/usb/atm/usbatm.c +++ b/drivers/usb/atm/usbatm.c @@ -602,8 +602,12 @@ static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb) vdbg("%s called (skb 0x%p, len %u)", __func__, skb, skb->len); - if (!instance) { - dbg("%s: NULL data!", __func__); + /* racy disconnection check - fine */ + if (!instance || instance->disconnected) { +#ifdef DEBUG + if (printk_ratelimit()) + printk(KERN_DEBUG "%s: %s!\n", __func__, instance ? "disconnected" : "NULL instance"); +#endif err = -ENODEV; goto fail; } @@ -715,15 +719,19 @@ static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t * pos, char *pag atomic_read(&atm_dev->stats.aal5.rx_err), atomic_read(&atm_dev->stats.aal5.rx_drop)); - if (!left--) - switch (atm_dev->signal) { - case ATM_PHY_SIG_FOUND: - return sprintf(page, "Line up\n"); - case ATM_PHY_SIG_LOST: - return sprintf(page, "Line down\n"); - default: - return sprintf(page, "Line state unknown\n"); - } + if (!left--) { + if (instance->disconnected) + return sprintf(page, "Disconnected\n"); + else + switch (atm_dev->signal) { + case ATM_PHY_SIG_FOUND: + return sprintf(page, "Line up\n"); + case ATM_PHY_SIG_LOST: + return sprintf(page, "Line down\n"); + default: + return sprintf(page, "Line state unknown\n"); + } + } return 0; } @@ -757,6 +765,12 @@ static int usbatm_atm_open(struct atm_vcc *vcc) down(&instance->serialize); /* vs self, usbatm_atm_close, usbatm_usb_disconnect */ + if (instance->disconnected) { + atm_dbg(instance, "%s: disconnected!\n", __func__); + ret = -ENODEV; + goto fail; + } + if (usbatm_find_vcc(instance, vpi, vci)) { atm_dbg(instance, "%s: %hd/%d already in use!\n", __func__, vpi, vci); ret = -EADDRINUSE; @@ -845,6 +859,13 @@ static void usbatm_atm_close(struct atm_vcc *vcc) static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd, void __user * arg) { + struct usbatm_data *instance = atm_dev->dev_data; + + if (!instance || instance->disconnected) { + dbg("%s: %s!", __func__, instance ? "disconnected" : "NULL instance"); + return -ENODEV; + } + switch (cmd) { case ATM_QUERYLOOP: return put_user(ATM_LM_NONE, (int __user *)arg) ? -EFAULT : 0; @@ -1129,6 +1150,7 @@ void usbatm_usb_disconnect(struct usb_interface *intf) { struct device *dev = &intf->dev; struct usbatm_data *instance = usb_get_intfdata(intf); + struct usbatm_vcc_data *vcc_data; int i; dev_dbg(dev, "%s entered\n", __func__); @@ -1141,12 +1163,18 @@ void usbatm_usb_disconnect(struct usb_interface *intf) usb_set_intfdata(intf, NULL); down(&instance->serialize); + instance->disconnected = 1; if (instance->thread_pid >= 0) kill_proc(instance->thread_pid, SIGTERM, 1); up(&instance->serialize); wait_for_completion(&instance->thread_exited); + down(&instance->serialize); + list_for_each_entry(vcc_data, &instance->vcc_list, list) + vcc_release_async(vcc_data->vcc, -EPIPE); + up(&instance->serialize); + tasklet_disable(&instance->rx_channel.tasklet); tasklet_disable(&instance->tx_channel.tasklet); @@ -1156,6 +1184,14 @@ void usbatm_usb_disconnect(struct usb_interface *intf) del_timer_sync(&instance->rx_channel.delay); del_timer_sync(&instance->tx_channel.delay); + /* turn usbatm_[rt]x_process into something close to a no-op */ + /* no need to take the spinlock */ + INIT_LIST_HEAD(&instance->rx_channel.list); + INIT_LIST_HEAD(&instance->tx_channel.list); + + tasklet_enable(&instance->rx_channel.tasklet); + tasklet_enable(&instance->tx_channel.tasklet); + if (instance->atm_dev && instance->driver->atm_stop) instance->driver->atm_stop(instance, instance->atm_dev); @@ -1164,14 +1200,6 @@ void usbatm_usb_disconnect(struct usb_interface *intf) instance->driver_data = NULL; - /* turn usbatm_[rt]x_process into noop */ - /* no need to take the spinlock */ - INIT_LIST_HEAD(&instance->rx_channel.list); - INIT_LIST_HEAD(&instance->tx_channel.list); - - tasklet_enable(&instance->rx_channel.tasklet); - tasklet_enable(&instance->tx_channel.tasklet); - for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) { kfree(instance->urbs[i]->transfer_buffer); usb_free_urb(instance->urbs[i]); diff --git a/drivers/usb/atm/usbatm.h b/drivers/usb/atm/usbatm.h index 4b923a8355..1a31cf87bb 100644 --- a/drivers/usb/atm/usbatm.h +++ b/drivers/usb/atm/usbatm.h @@ -168,6 +168,7 @@ struct usbatm_data { struct kref refcount; struct semaphore serialize; + int disconnected; /* heavy init */ int thread_pid;