From: Bjørn Mork <bjorn@mork.no>
Date: Sun, 2 Sep 2012 22:26:18 +0000 (+0000)
Subject: net: usbnet: fix softirq storm on suspend
X-Git-Tag: v3.6-rc6~18^2~41
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=85e87870fa18ec9f5df98e2d3b48f3699560a570;p=pandora-kernel.git

net: usbnet: fix softirq storm on suspend

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.

Cc: <stable@vger.kernel.org> # v3.5
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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