Re: [PATCH net] net: usbnet: fix softirq storm on suspend

From: Bjørn Mork <redacted>
Date: Mon,  3 Sep 2012 10:26:18 +0200

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: <redacted> # v3.5
Cc: Ming Lei <redacted>
Cc: Oliver Neukum <redacted>
Signed-off-by: Bjørn Mork <redacted>

Applied, thanks.
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