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authorMichael Grzeschik <m.grzeschik@pengutronix.de>2012-08-08 11:48:10 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-08-26 15:00:45 -0700
commit4cfb77e8eeddabbca1173a0a704c4065c62c4d05 (patch)
tree06192e73fe8e1a45e6dc1dd61059e5cd9906faa9
parent4893ce51af5c2ccdfabf8f7d34dd28cf84a8a06e (diff)
downloadlinux-linaro-stable-4cfb77e8eeddabbca1173a0a704c4065c62c4d05.tar.gz
usb: gadget: u_ether: fix kworker 100% CPU issue with still used interfaces in eth_stop
commit b1b552a69b8805e7e338074a9e8b670b4a795218 upstream. This patch fixes an issue introduced by patch: 72c973d usb: gadget: add usb_endpoint_descriptor to struct usb_ep Without this patch we see a kworker taking 100% CPU, after this sequence: - Connect gadget to a windows host - load g_ether - ifconfig up <ip>; ifconfig down; ifconfig up - ping <windows host> The "ifconfig down" results in calling eth_stop(), which will call usb_ep_disable() and, if the carrier is still ok, usb_ep_enable(): usb_ep_disable(link->in_ep); usb_ep_disable(link->out_ep); if (netif_carrier_ok(net)) { usb_ep_enable(link->in_ep); usb_ep_enable(link->out_ep); } The ep should stay enabled, but will not, as ep_disable set the desc pointer to NULL, therefore the subsequent ep_enable will fail. This leads to permanent rescheduling of the eth_work() worker as usb_ep_queue() (called by the worker) will fail due to the unconfigured endpoint. We fix this issue by saving the ep descriptors and re-assign them before usb_ep_enable(). Cc: Tatyana Brokhman <tlinder@codeaurora.org> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/gadget/u_ether.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index 4e1f0aaafcfe..9a2a1ae9b667 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c
@@ -669,6 +669,8 @@ static int eth_stop(struct net_device *net)
spin_lock_irqsave(&dev->lock, flags);
if (dev->port_usb) {
struct gether *link = dev->port_usb;
+ const struct usb_endpoint_descriptor *in;
+ const struct usb_endpoint_descriptor *out;
if (link->close)
link->close(link);
@@ -682,10 +684,14 @@ static int eth_stop(struct net_device *net)
* their own pace; the network stack can handle old packets.
* For the moment we leave this here, since it works.
*/
+ in = link->in_ep->desc;
+ out = link->out_ep->desc;
usb_ep_disable(link->in_ep);
usb_ep_disable(link->out_ep);
if (netif_carrier_ok(net)) {
DBG(dev, "host still using in/out endpoints\n");
+ link->in_ep->desc = in;
+ link->out_ep->desc = out;
usb_ep_enable(link->in_ep);
usb_ep_enable(link->out_ep);
}