| From | Greg Kroah-Hartman <> | Subject | [ 116/262] net: usbnet: fix softirq storm on suspend | Date | Fri, 28 Sep 2012 11:50:45 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bjørn Mork <bjorn@mork.no>
commit 85e87870fa18ec9f5df98e2d3b48f3699560a570 upstream.
Suspending an open usbnet device results in constant rescheduling of usbnet_bh.
commit 65841fd5 "usbnet: handle remote wakeup asap" refactored the usbnet_bh code to allow sharing the urb allocate and submit code with usbnet_resume. In this process, a test for, and immediate return on, ENOLINK from rx_submit was unintentionally dropped.
The rx queue will not grow if rx_submit fails, making usbnet_bh reschedule itself. This results in a softirq storm if the error is persistent. rx_submit translates the usb_submit_urb error EHOSTUNREACH into ENOLINK, so this is an expected and persistent error for a suspended device. The old code tested for this condition and avoided rescheduling. Putting this test back.
Signed-off-by: Bjørn Mork <bjorn@mork.no> Cc: Ming Lei <ming.lei@canonical.com> Cc: Oliver Neukum <oneukum@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/net/usb/usbnet.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
--- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1204,19 +1204,26 @@ deferred: } EXPORT_SYMBOL_GPL(usbnet_start_xmit); -static void rx_alloc_submit(struct usbnet *dev, gfp_t flags) +static int rx_alloc_submit(struct usbnet *dev, gfp_t flags) { struct urb *urb; int i; + int ret = 0; /* don't refill the queue all at once */ for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) { urb = usb_alloc_urb(0, flags); if (urb != NULL) { - if (rx_submit(dev, urb, flags) == -ENOLINK) - return; + ret = rx_submit(dev, urb, flags); + if (ret) + goto err; + } else { + ret = -ENOMEM; + goto err; } } +err: + return ret; } /*-------------------------------------------------------------------------*/ @@ -1260,7 +1267,8 @@ static void usbnet_bh (unsigned long par int temp = dev->rxq.qlen; if (temp < RX_QLEN(dev)) { - rx_alloc_submit(dev, GFP_ATOMIC); + if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK) + return; if (temp != dev->rxq.qlen) netif_dbg(dev, link, dev->net, "rxqlen %d --> %d\n",
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